Re: [time-nuts] GPS ANTENNA

[Bob kb8tq]

Hi

The problem with “to much gain” is that it is very hard to tell when you have 
to much gain. 
The system quite happily chugs along reporting fine S/N ratios. Cut the gain by 
20 db and
you get the same C/N ratios. The reason is pretty simple - the noise figure is 
set by the 
front end of the preamp. As long as you have “enough” gain it will dominate. Is 
“enough”
10 db or 100 db? Either way it’s enough to make that equation work.

The issue comes in mainly because these modules have a limited AGC range (or 
dynamic
range). For whatever reason, the AGC situation is not reported upstream. If the 
module has
run out of AGC and is about to loose it …. you simply have no way to tell. 

It’s not just TimeNuts that have trouble with this stuff. Very large / smart / 
big budget / outfits
run into this stuff as well. The same issues of poorly documented system 
requirements / 
non-standard system requirements are a major hassle for them. I’ve seen them 
spend 
major effort because of this stuff. 

So how to work it out? 

Stuff a (dc blocked) variable attenuator in the line. Pick a sat that is 
reporting something like
35 db S/N. Flip between two attenuator settings every 30 seconds or so. Note 
any change. 
Do it multiple times with multiple sats. Then move on to your next settings 
pair. I’d start big,
maybe a 10 db step and go smaller if you can stand the boredom. 

As long as 35 db stays roughly 35 db, you have “enough” gain. Since sat’s move 
and that 
impacts S/N, there is no exact 0.05 db sort of number. Even looking at numbers 
over a day
can be tricky. Things are never quite the same today as they were yesterday. 

It does seem strange that you want the minimum gain. It’s not so strange if you 
dig into things
like land mobile radio design. Your best overload performance is always going 
to be the 
design with barely enough gain in the front end. 

Lots of fun. 

Bob

> On Apr 2, 2018, at 6:07 AM, ew via time-nuts  wrote:
> 
> Question
> Using L/H  what is too much signal 
> Bert Kehren
>  
> In a message dated 4/1/2018 10:54:23 PM Eastern Standard Time, 
> david.partri...@perdrix.co.uk writes:
> 
>  
> just use a bias tee to feed in the antenna volts :)
> 
> -Original Message-
> From: time-nuts [mailto:time-nuts-boun...@febo.com] On Behalf Of Azelio 
> Boriani
> Sent: 01 April 2018 23:29
> To: Discussion of precise time and frequency measurement
> Subject: Re: [time-nuts] GPS ANTENNA
> 
> An unusual attenuator with a DC pass.
> 
> On Sun, Apr 1, 2018 at 10:21 PM, David C. Partridge 
>  wrote:
>> Or use a choke ring survey antenna and an attenuator :)
>> 
>> Dave
>> 
>> -Original Message-
>> From: time-nuts [mailto:time-nuts-boun...@febo.com] On Behalf Of Bob 
>> kb8tq
>> Sent: 01 April 2018 14:43
>> To: Discussion of precise time and frequency measurement
>> Subject: Re: [time-nuts] GPS ANTENNA
>> 
>> Hi
>> 
>> Indeed, it is *very* easy to put to much gain in front of a timing GNSS 
>> receiver. These beasts are trying to dig out a signal that you can’t even 
>> see with a spectrum analyzer.
>> It’s way to far below the noise floor to detect that way. They optimize 
>> things pretty tightly to get that done (and to hit a price target ….). Put 
>> to much gain in front of them and they get unhappy.
>> 
>> Making this even more crazy, the survey industry standard antenna *does* 
>> have a lot of gain. Survey receivers need way more gain in front of them 
>> than timing receivers. Put a survey antenna directly on a timing device and 
>> trouble will likely be the outcome. Equally, a survey instrument probably 
>> will not be happy with a timing receiver.
>> 
>> Why all this nonsense? As far as I can tell, it goes back to how the very 
>> early L1 / L2 survey boxes were designed back in the 1980’s and early 
>> 1990’s. They made a basic decision to put a lot of gain at the antenna. 
>> Motorola came along with their GPS modules later on. They made a *very* 
>> different decision about how to distribute the gain. There are very good 
>> arguments on both sides for why they did it this way.
>> The bottom line is still - you need to match things up …
>> 
>> Bob
>> 
>>> On Apr 1, 2018, at 2:36 AM, cfo  wrote:
>>> 
>>> On Sat, 31 Mar 2018 10:58:19 -0500,
>>> donandarline-Re5JQEeQqe8AvxtiuMwx3w
>>> wrote:
>>> 
>>>> I found a supplier for high quality GPS antennas at a very 
>>>> reasonable price. PCTEL GPSL1-TMG-SPI-40NCB.
>>> 
>>> *** SNIP ***
>>> 
>>> I had one of those on 25m cable, and it worked fine on a Tbolt , 
>>> until i got an active antenna splitter that also had some gain.
>&

Re: [time-nuts] GPS ANTENNA

[Bob kb8tq]

Hi

As you rummage around your junk box, do be a bit careful Most of what I have 
here are
tee’s that include DC blocks. There are blocks that don’t do that. Trying to 
run your bias
supply into 50 or 25 ohms is not a real good idea.

Bob

> On Apr 1, 2018, at 9:43 PM, David C. Partridge 
>  wrote:
> 
> just use a bias tee to feed in the antenna volts :)
> 
> -Original Message-
> From: time-nuts [mailto:time-nuts-boun...@febo.com] On Behalf Of Azelio 
> Boriani
> Sent: 01 April 2018 23:29
> To: Discussion of precise time and frequency measurement
> Subject: Re: [time-nuts] GPS ANTENNA
> 
> An unusual attenuator with a DC pass.
> 
> On Sun, Apr 1, 2018 at 10:21 PM, David C. Partridge 
>  wrote:
>> Or use a choke ring survey antenna and an attenuator :)
>> 
>> Dave
>> 
>> -Original Message-
>> From: time-nuts [mailto:time-nuts-boun...@febo.com] On Behalf Of Bob 
>> kb8tq
>> Sent: 01 April 2018 14:43
>> To: Discussion of precise time and frequency measurement
>> Subject: Re: [time-nuts] GPS ANTENNA
>> 
>> Hi
>> 
>> Indeed, it is *very* easy to put to much gain in front of a timing GNSS 
>> receiver. These beasts are trying to dig out a signal that you can’t even 
>> see with a spectrum analyzer.
>> It’s way to far below the noise floor to detect that way. They optimize 
>> things pretty tightly to get that done (and to hit a price target ….). Put 
>> to much gain in front of them and they get unhappy.
>> 
>> Making this even more crazy, the survey industry standard antenna *does* 
>> have a lot of gain. Survey receivers need way more gain in front of them 
>> than timing receivers. Put a survey antenna directly on a timing device and 
>> trouble will likely be the outcome. Equally, a survey instrument probably 
>> will not be happy with a timing receiver.
>> 
>> Why all this nonsense? As far as I can tell, it goes back to how the very 
>> early L1 / L2 survey boxes were designed back in the 1980’s and early 
>> 1990’s. They made a basic decision to put a lot of gain at the antenna. 
>> Motorola came along with their GPS modules later on. They made a *very* 
>> different decision about how to distribute the gain. There are very good 
>> arguments on both sides for why they did it this way.
>> The bottom line is still - you need to match things up …
>> 
>> Bob
>> 
>>> On Apr 1, 2018, at 2:36 AM, cfo  wrote:
>>> 
>>> On Sat, 31 Mar 2018 10:58:19 -0500,
>>> donandarline-Re5JQEeQqe8AvxtiuMwx3w
>>> wrote:
>>> 
>>>> I found a supplier for high quality GPS antennas at a very 
>>>> reasonable price. PCTEL GPSL1-TMG-SPI-40NCB.
>>> 
>>> *** SNIP ***
>>> 
>>> I had one of those on 25m cable, and it worked fine on a Tbolt , 
>>> until i got an active antenna splitter that also had some gain.
>>> Then i had to replace it w. a 26dB version of same type, else the 
>>> "Jackson Lite" was loosing sync.
>>> 
>>> What i mean here, is that you can get too much gain too.
>>> 
>>> Btw: Good price.
>>> 
>>> CFO
>>> Denmark
>>> 
>>> ___
>>> time-nuts mailing list -- time-nuts@febo.com To unsubscribe, go to 
>>> https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts
>>> and follow the instructions there.
>> 
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Re: [time-nuts] GPS ANTENNA

[ew via time-nuts]

Question
Using L/H  what is too much signal 
Bert Kehren
 
In a message dated 4/1/2018 10:54:23 PM Eastern Standard Time, 
david.partri...@perdrix.co.uk writes:

 
 just use a bias tee to feed in the antenna volts :)

-Original Message-
From: time-nuts [mailto:time-nuts-boun...@febo.com] On Behalf Of Azelio Boriani
Sent: 01 April 2018 23:29
To: Discussion of precise time and frequency measurement
Subject: Re: [time-nuts] GPS ANTENNA

An unusual attenuator with a DC pass.

On Sun, Apr 1, 2018 at 10:21 PM, David C. Partridge 
 wrote:
> Or use a choke ring survey antenna and an attenuator :)
>
> Dave
>
> -Original Message-
> From: time-nuts [mailto:time-nuts-boun...@febo.com] On Behalf Of Bob 
> kb8tq
> Sent: 01 April 2018 14:43
> To: Discussion of precise time and frequency measurement
> Subject: Re: [time-nuts] GPS ANTENNA
>
> Hi
>
> Indeed, it is *very* easy to put to much gain in front of a timing GNSS 
> receiver. These beasts are trying to dig out a signal that you can’t even see 
> with a spectrum analyzer.
> It’s way to far below the noise floor to detect that way. They optimize 
> things pretty tightly to get that done (and to hit a price target ….). Put to 
> much gain in front of them and they get unhappy.
>
> Making this even more crazy, the survey industry standard antenna *does* have 
> a lot of gain. Survey receivers need way more gain in front of them than 
> timing receivers. Put a survey antenna directly on a timing device and 
> trouble will likely be the outcome. Equally, a survey instrument probably 
> will not be happy with a timing receiver.
>
> Why all this nonsense? As far as I can tell, it goes back to how the very 
> early L1 / L2 survey boxes were designed back in the 1980’s and early 1990’s. 
> They made a basic decision to put a lot of gain at the antenna. Motorola came 
> along with their GPS modules later on. They made a *very* different decision 
> about how to distribute the gain. There are very good arguments on both sides 
> for why they did it this way.
> The bottom line is still - you need to match things up …
>
> Bob
>
>> On Apr 1, 2018, at 2:36 AM, cfo  wrote:
>>
>> On Sat, 31 Mar 2018 10:58:19 -0500,
>> donandarline-Re5JQEeQqe8AvxtiuMwx3w
>> wrote:
>>
>>> I found a supplier for high quality GPS antennas at a very 
>>> reasonable price. PCTEL GPSL1-TMG-SPI-40NCB.
>>
>> *** SNIP ***
>>
>> I had one of those on 25m cable, and it worked fine on a Tbolt , 
>> until i got an active antenna splitter that also had some gain.
>> Then i had to replace it w. a 26dB version of same type, else the 
>> "Jackson Lite" was loosing sync.
>>
>> What i mean here, is that you can get too much gain too.
>>
>> Btw: Good price.
>>
>> CFO
>> Denmark
>>
>> ___
>> time-nuts mailing list -- time-nuts@febo.com To unsubscribe, go to 
>> https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts
>> and follow the instructions there.
>
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>
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Re: [time-nuts] GPS ANTENNA

[Björn]

Or find an Arra “level set” variable attenuator. 3844 and 3854 models can often 
be found cheaply, have dc-pass and attenuate at both L1 and L2.

/Björn 

Sent from my iPhone

> On 2 Apr 2018, at 03:43, David C. Partridge  
> wrote:
> 
> just use a bias tee to feed in the antenna volts :)
> 
> -Original Message-
> From: time-nuts [mailto:time-nuts-boun...@febo.com] On Behalf Of Azelio 
> Boriani
> Sent: 01 April 2018 23:29
> To: Discussion of precise time and frequency measurement
> Subject: Re: [time-nuts] GPS ANTENNA
> 
> An unusual attenuator with a DC pass.
> 
>> On Sun, Apr 1, 2018 at 10:21 PM, David C. Partridge 
>>  wrote:
>> Or use a choke ring survey antenna and an attenuator :)
>> 
>> Dave
>> 
>> -Original Message-
>> From: time-nuts [mailto:time-nuts-boun...@febo.com] On Behalf Of Bob 
>> kb8tq
>> Sent: 01 April 2018 14:43
>> To: Discussion of precise time and frequency measurement
>> Subject: Re: [time-nuts] GPS ANTENNA
>> 
>> Hi
>> 
>> Indeed, it is *very* easy to put to much gain in front of a timing GNSS 
>> receiver. These beasts are trying to dig out a signal that you can’t even 
>> see with a spectrum analyzer.
>> It’s way to far below the noise floor to detect that way. They optimize 
>> things pretty tightly to get that done (and to hit a price target ….). Put 
>> to much gain in front of them and they get unhappy.
>> 
>> Making this even more crazy, the survey industry standard antenna *does* 
>> have a lot of gain. Survey receivers need way more gain in front of them 
>> than timing receivers. Put a survey antenna directly on a timing device and 
>> trouble will likely be the outcome. Equally, a survey instrument probably 
>> will not be happy with a timing receiver.
>> 
>> Why all this nonsense? As far as I can tell, it goes back to how the very 
>> early L1 / L2 survey boxes were designed back in the 1980’s and early 
>> 1990’s. They made a basic decision to put a lot of gain at the antenna. 
>> Motorola came along with their GPS modules later on. They made a *very* 
>> different decision about how to distribute the gain. There are very good 
>> arguments on both sides for why they did it this way.
>> The bottom line is still - you need to match things up …
>> 
>> Bob
>> 
>>> On Apr 1, 2018, at 2:36 AM, cfo  wrote:
>>> 
>>> On Sat, 31 Mar 2018 10:58:19 -0500,
>>> donandarline-Re5JQEeQqe8AvxtiuMwx3w
>>> wrote:
>>> 
>>>> I found a supplier for high quality GPS antennas at a very 
>>>> reasonable price. PCTEL GPSL1-TMG-SPI-40NCB.
>>> 
>>> *** SNIP ***
>>> 
>>> I had one of those on 25m cable, and it worked fine on a Tbolt , 
>>> until i got an active antenna splitter that also had some gain.
>>> Then i had to replace it w. a 26dB version of same type, else the 
>>> "Jackson Lite" was loosing sync.
>>> 
>>> What i mean here, is that you can get too much gain too.
>>> 
>>> Btw: Good price.
>>> 
>>> CFO
>>> Denmark
>>> 
>>> ___
>>> time-nuts mailing list -- time-nuts@febo.com To unsubscribe, go to 
>>> https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts
>>> and follow the instructions there.
>> 
>> ___
>> time-nuts mailing list -- time-nuts@febo.com To unsubscribe, go to 
>> https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts
>> and follow the instructions there.
>> 
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>> https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts
>> and follow the instructions there.
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[time-nuts] GPS antenna gain

[Tisha Hayes]

I had the misfortune of using those very PCTEL antennas in a timing
application and excessive gain was a problem with the loss of frame sync
whenever the receiver had too much signal from any satellite. It was a
highly intermittent problem that appeared every few days; always after I
had tested and verified things were working, a failure would happen in the
middle of the night, the day after I flew home.

Of course I had made all of the "terrible choices" of making sure that the
antennas had a clear shot to the sky and coax cable lengths were minimized
to reduce loss. After a few weeks of fighting the issue the solution ended
up being 10 dB attenuators that could pass DC bias.

The WiMAX radio manufacturer initially insisted that I ordered third-party
GPS timing antennas from somewhere and ignored (their not documented)
specification. It got ugly until I provided the invoice showing that I
bought those over-amped up antennas from them, right out of their parts
list.

I still have a few of those antennas floating around here in the house.

*Ms. Tisha Hayes, AA4HA*
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Re: [time-nuts] GPS ANTENNA

[David C. Partridge]

just use a bias tee to feed in the antenna volts :)

-Original Message-
From: time-nuts [mailto:time-nuts-boun...@febo.com] On Behalf Of Azelio Boriani
Sent: 01 April 2018 23:29
To: Discussion of precise time and frequency measurement
Subject: Re: [time-nuts] GPS ANTENNA

An unusual attenuator with a DC pass.

On Sun, Apr 1, 2018 at 10:21 PM, David C. Partridge 
 wrote:
> Or use a choke ring survey antenna and an attenuator :)
>
> Dave
>
> -Original Message-
> From: time-nuts [mailto:time-nuts-boun...@febo.com] On Behalf Of Bob 
> kb8tq
> Sent: 01 April 2018 14:43
> To: Discussion of precise time and frequency measurement
> Subject: Re: [time-nuts] GPS ANTENNA
>
> Hi
>
> Indeed, it is *very* easy to put to much gain in front of a timing GNSS 
> receiver. These beasts are trying to dig out a signal that you can’t even see 
> with a spectrum analyzer.
> It’s way to far below the noise floor to detect that way. They optimize 
> things pretty tightly to get that done (and to hit a price target ….). Put to 
> much gain in front of them and they get unhappy.
>
> Making this even more crazy, the survey industry standard antenna *does* have 
> a lot of gain. Survey receivers need way more gain in front of them than 
> timing receivers. Put a survey antenna directly on a timing device and 
> trouble will likely be the outcome. Equally, a survey instrument probably 
> will not be happy with a timing receiver.
>
> Why all this nonsense? As far as I can tell, it goes back to how the very 
> early L1 / L2 survey boxes were designed back in the 1980’s and early 1990’s. 
> They made a basic decision to put a lot of gain at the antenna. Motorola came 
> along with their GPS modules later on. They made a *very* different decision 
> about how to distribute the gain. There are very good arguments on both sides 
> for why they did it this way.
> The bottom line is still - you need to match things up …
>
> Bob
>
>> On Apr 1, 2018, at 2:36 AM, cfo  wrote:
>>
>> On Sat, 31 Mar 2018 10:58:19 -0500,
>> donandarline-Re5JQEeQqe8AvxtiuMwx3w
>> wrote:
>>
>>> I found a supplier for high quality GPS antennas at a very 
>>> reasonable price. PCTEL GPSL1-TMG-SPI-40NCB.
>>
>> *** SNIP ***
>>
>> I had one of those on 25m cable, and it worked fine on a Tbolt , 
>> until i got an active antenna splitter that also had some gain.
>> Then i had to replace it w. a 26dB version of same type, else the 
>> "Jackson Lite" was loosing sync.
>>
>> What i mean here, is that you can get too much gain too.
>>
>> Btw: Good price.
>>
>> CFO
>> Denmark
>>
>> ___
>> time-nuts mailing list -- time-nuts@febo.com To unsubscribe, go to 
>> https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts
>> and follow the instructions there.
>
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>
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Re: [time-nuts] GPS ANTENNA

[Bruce Griffiths]

Just use a standard attenuator between a pair of bias T's with their dc ports 
connected together.

Bruce

> 
> On 02 April 2018 at 10:29 Azelio Boriani  wrote:
> 
> An unusual attenuator with a DC pass.
> 
> On Sun, Apr 1, 2018 at 10:21 PM, David C. Partridge
> 
>  wrote:
> 
> > > 
> > Or use a choke ring survey antenna and an attenuator :)
> > 
> > Dave
> > 
> > -Original Message-
> > From: time-nuts [mailto:time-nuts-boun...@febo.com] On Behalf Of 
> > Bob kb8tq
> > Sent: 01 April 2018 14:43
> >     To: Discussion of precise time and frequency measurement
> > Subject: Re: [time-nuts] GPS ANTENNA
> > 
> > Hi
> > 
> > Indeed, it is *very* easy to put to much gain in front of a timing 
> > GNSS receiver. These beasts are trying to dig out a signal that you can’t 
> > even see with a spectrum analyzer.
> > It’s way to far below the noise floor to detect that way. They 
> > optimize things pretty tightly to get that done (and to hit a price target 
> > ….). Put to much gain in front of them and they get unhappy.
> > 
> > Making this even more crazy, the survey industry standard antenna 
> > *does* have a lot of gain. Survey receivers need way more gain in front of 
> > them than timing receivers. Put a survey antenna directly on a timing 
> > device and trouble will likely be the outcome. Equally, a survey instrument 
> > probably will not be happy with a timing receiver.
> > 
> > Why all this nonsense? As far as I can tell, it goes back to how 
> > the very early L1 / L2 survey boxes were designed back in the 1980’s and 
> > early 1990’s. They made a basic decision to put a lot of gain at the 
> > antenna. Motorola came along with their GPS modules later on. They made a 
> > *very* different decision about how to distribute the gain. There are very 
> > good arguments on both sides for why they did it this way.
> > The bottom line is still - you need to match things up …
> > 
> > Bob
> > 
> > > > > 
> > > On Apr 1, 2018, at 2:36 AM, cfo  wrote:
> > > 
> > > On Sat, 31 Mar 2018 10:58:19 -0500,
> > > donandarline-Re5JQEeQqe8AvxtiuMwx3w
> > > wrote:
> > > 
> > > > > > > 
> > > > I found a supplier for high quality GPS antennas at a 
> > > > very reasonable
> > > > price. PCTEL GPSL1-TMG-SPI-40NCB.
> > > > 
> > > > > > > 
> > > *** SNIP ***
> > > 
> > > I had one of those on 25m cable, and it worked fine on a 
> > > Tbolt , until
> > > i got an active antenna splitter that also had some gain.
> > > Then i had to replace it w. a 26dB version of same type, else 
> > > the
> > > "Jackson Lite" was loosing sync.
> > > 
> > > What i mean here, is that you can get too much gain too.
> > > 
> > > Btw: Good price.
> > > 
> > > CFO
> > > Denmark
> > > 
> > > ___
> > > time-nuts mailing list -- time-nuts@febo.com To unsubscribe, 
> > > go to
> > > https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts
> > > and follow the instructions there.
> > > 
> > > > > 
> > ___
> > time-nuts mailing list -- time-nuts@febo.com To unsubscribe, go to 
> > https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts
> > and follow the instructions there.
> > 
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> > and follow the instructions there.
> > 
> > > 
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Re: [time-nuts] GPS ANTENNA

[Bob kb8tq]

Hi

They are indeed a bit unusual. Generally you do a DC block and bias tee ahead 
of the 
attenuator. For a “self contained” approach, a second block and bias tee pulls 
the DC
of the GPSDO side of the attenuator.  My preference has been to just run the 
bias tee
with an external DC source. 

Bob

> On Apr 1, 2018, at 6:29 PM, Azelio Boriani  wrote:
> 
> An unusual attenuator with a DC pass.
> 
> On Sun, Apr 1, 2018 at 10:21 PM, David C. Partridge
>  wrote:
>> Or use a choke ring survey antenna and an attenuator :)
>> 
>> Dave
>> 
>> -Original Message-
>> From: time-nuts [mailto:time-nuts-boun...@febo.com] On Behalf Of Bob kb8tq
>> Sent: 01 April 2018 14:43
>> To: Discussion of precise time and frequency measurement
>> Subject: Re: [time-nuts] GPS ANTENNA
>> 
>> Hi
>> 
>> Indeed, it is *very* easy to put to much gain in front of a timing GNSS 
>> receiver. These beasts are trying to dig out a signal that you can’t even 
>> see with a spectrum analyzer.
>> It’s way to far below the noise floor to detect that way. They optimize 
>> things pretty tightly to get that done (and to hit a price target ….). Put 
>> to much gain in front of them and they get unhappy.
>> 
>> Making this even more crazy, the survey industry standard antenna *does* 
>> have a lot of gain. Survey receivers need way more gain in front of them 
>> than timing receivers. Put a survey antenna directly on a timing device and 
>> trouble will likely be the outcome. Equally, a survey instrument probably 
>> will not be happy with a timing receiver.
>> 
>> Why all this nonsense? As far as I can tell, it goes back to how the very 
>> early L1 / L2 survey boxes were designed back in the 1980’s and early 
>> 1990’s. They made a basic decision to put a lot of gain at the antenna. 
>> Motorola came along with their GPS modules later on. They made a *very* 
>> different decision about how to distribute the gain. There are very good 
>> arguments on both sides for why they did it this way.
>> The bottom line is still - you need to match things up …
>> 
>> Bob
>> 
>>> On Apr 1, 2018, at 2:36 AM, cfo  wrote:
>>> 
>>> On Sat, 31 Mar 2018 10:58:19 -0500,
>>> donandarline-Re5JQEeQqe8AvxtiuMwx3w
>>> wrote:
>>> 
>>>> I found a supplier for high quality GPS antennas at a very reasonable
>>>> price. PCTEL GPSL1-TMG-SPI-40NCB.
>>> 
>>> *** SNIP ***
>>> 
>>> I had one of those on 25m cable, and it worked fine on a Tbolt , until
>>> i got an active antenna splitter that also had some gain.
>>> Then i had to replace it w. a 26dB version of same type, else the
>>> "Jackson Lite" was loosing sync.
>>> 
>>> What i mean here, is that you can get too much gain too.
>>> 
>>> Btw: Good price.
>>> 
>>> CFO
>>> Denmark
>>> 
>>> ___
>>> time-nuts mailing list -- time-nuts@febo.com To unsubscribe, go to
>>> https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts
>>> and follow the instructions there.
>> 
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Re: [time-nuts] GPS ANTENNA

[jimlux]

On 4/1/18 3:29 PM, Azelio Boriani wrote:

An unusual attenuator with a DC pass.



A few feet of RG-174 (or any 0.1" diameter coax) would probably work.





On Sun, Apr 1, 2018 at 10:21 PM, David C. Partridge
 wrote:

Or use a choke ring survey antenna and an attenuator :)

Dave

-Original Message-
From: time-nuts [mailto:time-nuts-boun...@febo.com] On Behalf Of Bob kb8tq
Sent: 01 April 2018 14:43
To: Discussion of precise time and frequency measurement
Subject: Re: [time-nuts] GPS ANTENNA

Hi

Indeed, it is *very* easy to put to much gain in front of a timing GNSS 
receiver. These beasts are trying to dig out a signal that you can’t even see 
with a spectrum analyzer.
It’s way to far below the noise floor to detect that way. They optimize things 
pretty tightly to get that done (and to hit a price target ….). Put to much 
gain in front of them and they get unhappy.

Making this even more crazy, the survey industry standard antenna *does* have a 
lot of gain. Survey receivers need way more gain in front of them than timing 
receivers. Put a survey antenna directly on a timing device and trouble will 
likely be the outcome. Equally, a survey instrument probably will not be happy 
with a timing receiver.

Why all this nonsense? As far as I can tell, it goes back to how the very early 
L1 / L2 survey boxes were designed back in the 1980’s and early 1990’s. They 
made a basic decision to put a lot of gain at the antenna. Motorola came along 
with their GPS modules later on. They made a *very* different decision about 
how to distribute the gain. There are very good arguments on both sides for why 
they did it this way.
The bottom line is still - you need to match things up …

Bob


On Apr 1, 2018, at 2:36 AM, cfo  wrote:

On Sat, 31 Mar 2018 10:58:19 -0500,
donandarline-Re5JQEeQqe8AvxtiuMwx3w
wrote:


I found a supplier for high quality GPS antennas at a very reasonable
price. PCTEL GPSL1-TMG-SPI-40NCB.


*** SNIP ***

I had one of those on 25m cable, and it worked fine on a Tbolt , until
i got an active antenna splitter that also had some gain.
Then i had to replace it w. a 26dB version of same type, else the
"Jackson Lite" was loosing sync.

What i mean here, is that you can get too much gain too.

Btw: Good price.

CFO
Denmark

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Re: [time-nuts] GPS ANTENNA

[Azelio Boriani]

An unusual attenuator with a DC pass.

On Sun, Apr 1, 2018 at 10:21 PM, David C. Partridge
 wrote:
> Or use a choke ring survey antenna and an attenuator :)
>
> Dave
>
> -Original Message-
> From: time-nuts [mailto:time-nuts-boun...@febo.com] On Behalf Of Bob kb8tq
> Sent: 01 April 2018 14:43
> To: Discussion of precise time and frequency measurement
> Subject: Re: [time-nuts] GPS ANTENNA
>
> Hi
>
> Indeed, it is *very* easy to put to much gain in front of a timing GNSS 
> receiver. These beasts are trying to dig out a signal that you can’t even see 
> with a spectrum analyzer.
> It’s way to far below the noise floor to detect that way. They optimize 
> things pretty tightly to get that done (and to hit a price target ….). Put to 
> much gain in front of them and they get unhappy.
>
> Making this even more crazy, the survey industry standard antenna *does* have 
> a lot of gain. Survey receivers need way more gain in front of them than 
> timing receivers. Put a survey antenna directly on a timing device and 
> trouble will likely be the outcome. Equally, a survey instrument probably 
> will not be happy with a timing receiver.
>
> Why all this nonsense? As far as I can tell, it goes back to how the very 
> early L1 / L2 survey boxes were designed back in the 1980’s and early 1990’s. 
> They made a basic decision to put a lot of gain at the antenna. Motorola came 
> along with their GPS modules later on. They made a *very* different decision 
> about how to distribute the gain. There are very good arguments on both sides 
> for why they did it this way.
> The bottom line is still - you need to match things up …
>
> Bob
>
>> On Apr 1, 2018, at 2:36 AM, cfo  wrote:
>>
>> On Sat, 31 Mar 2018 10:58:19 -0500,
>> donandarline-Re5JQEeQqe8AvxtiuMwx3w
>> wrote:
>>
>>> I found a supplier for high quality GPS antennas at a very reasonable
>>> price. PCTEL GPSL1-TMG-SPI-40NCB.
>>
>> *** SNIP ***
>>
>> I had one of those on 25m cable, and it worked fine on a Tbolt , until
>> i got an active antenna splitter that also had some gain.
>> Then i had to replace it w. a 26dB version of same type, else the
>> "Jackson Lite" was loosing sync.
>>
>> What i mean here, is that you can get too much gain too.
>>
>> Btw: Good price.
>>
>> CFO
>> Denmark
>>
>> ___
>> time-nuts mailing list -- time-nuts@febo.com To unsubscribe, go to
>> https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts
>> and follow the instructions there.
>
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> https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts
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Re: [time-nuts] GPS ANTENNA

[David C. Partridge]

Or use a choke ring survey antenna and an attenuator :)

Dave

-Original Message-
From: time-nuts [mailto:time-nuts-boun...@febo.com] On Behalf Of Bob kb8tq
Sent: 01 April 2018 14:43
To: Discussion of precise time and frequency measurement
Subject: Re: [time-nuts] GPS ANTENNA

Hi

Indeed, it is *very* easy to put to much gain in front of a timing GNSS 
receiver. These beasts are trying to dig out a signal that you can’t even see 
with a spectrum analyzer.
It’s way to far below the noise floor to detect that way. They optimize things 
pretty tightly to get that done (and to hit a price target ….). Put to much 
gain in front of them and they get unhappy. 

Making this even more crazy, the survey industry standard antenna *does* have a 
lot of gain. Survey receivers need way more gain in front of them than timing 
receivers. Put a survey antenna directly on a timing device and trouble will 
likely be the outcome. Equally, a survey instrument probably will not be happy 
with a timing receiver. 

Why all this nonsense? As far as I can tell, it goes back to how the very early 
L1 / L2 survey boxes were designed back in the 1980’s and early 1990’s. They 
made a basic decision to put a lot of gain at the antenna. Motorola came along 
with their GPS modules later on. They made a *very* different decision about 
how to distribute the gain. There are very good arguments on both sides for why 
they did it this way. 
The bottom line is still - you need to match things up …

Bob

> On Apr 1, 2018, at 2:36 AM, cfo  wrote:
> 
> On Sat, 31 Mar 2018 10:58:19 -0500, 
> donandarline-Re5JQEeQqe8AvxtiuMwx3w
> wrote:
> 
>> I found a supplier for high quality GPS antennas at a very reasonable 
>> price. PCTEL GPSL1-TMG-SPI-40NCB.
> 
> *** SNIP ***
> 
> I had one of those on 25m cable, and it worked fine on a Tbolt , until 
> i got an active antenna splitter that also had some gain.
> Then i had to replace it w. a 26dB version of same type, else the 
> "Jackson Lite" was loosing sync.
> 
> What i mean here, is that you can get too much gain too.
> 
> Btw: Good price.
> 
> CFO
> Denmark
> 
> ___
> time-nuts mailing list -- time-nuts@febo.com To unsubscribe, go to 
> https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts
> and follow the instructions there.

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Re: [time-nuts] GPS ANTENNA

[Bob kb8tq]

Hi

Indeed, it is *very* easy to put to much gain in front of a timing GNSS 
receiver. These 
beasts are trying to dig out a signal that you can’t even see with a spectrum 
analyzer.
It’s way to far below the noise floor to detect that way. They optimize things 
pretty
tightly to get that done (and to hit a price target ….). Put to much gain in 
front of 
them and they get unhappy. 

Making this even more crazy, the survey industry standard antenna *does* have
a lot of gain. Survey receivers need way more gain in front of them than timing 
receivers. Put a survey antenna directly on a timing device and trouble will 
likely be the 
outcome. Equally, a survey instrument probably will not be happy with a timing 
receiver. 

Why all this nonsense? As far as I can tell, it goes back to how the very early 
L1 / L2
survey boxes were designed back in the 1980’s and early 1990’s. They made a 
basic decision to put a lot of gain at the antenna. Motorola came along with 
their 
GPS modules later on. They made a *very* different decision about how to 
distribute
the gain. There are very good arguments on both sides for why they did it this 
way. 
The bottom line is still - you need to match things up …

Bob

> On Apr 1, 2018, at 2:36 AM, cfo  wrote:
> 
> On Sat, 31 Mar 2018 10:58:19 -0500, donandarline-Re5JQEeQqe8AvxtiuMwx3w
> wrote:
> 
>> I found a supplier for high quality GPS antennas at a very reasonable
>> price. PCTEL GPSL1-TMG-SPI-40NCB.
> 
> *** SNIP ***
> 
> I had one of those on 25m cable, and it worked fine on a Tbolt , until
> i got an active antenna splitter that also had some gain.
> Then i had to replace it w. a 26dB version of same type, else the
> "Jackson Lite" was loosing sync.
> 
> What i mean here, is that you can get too much gain too.
> 
> Btw: Good price.
> 
> CFO
> Denmark
> 
> ___
> time-nuts mailing list -- time-nuts@febo.com
> To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts
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Re: [time-nuts] GPS ANTENNA

[cfo]

On Sat, 31 Mar 2018 10:58:19 -0500, donandarline-Re5JQEeQqe8AvxtiuMwx3w
wrote:

> I found a supplier for high quality GPS antennas at a very reasonable
> price. PCTEL GPSL1-TMG-SPI-40NCB.

*** SNIP ***

I had one of those on 25m cable, and it worked fine on a Tbolt , until
i got an active antenna splitter that also had some gain.
Then i had to replace it w. a 26dB version of same type, else the
"Jackson Lite" was loosing sync.

What i mean here, is that you can get too much gain too.

Btw: Good price.

CFO
Denmark

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[time-nuts] GPS ANTENNA

[donandarline]

I found a supplier for high quality GPS antennas at a very reasonable price.
PCTEL GPSL1-TMG-SPI-40NCB.
They have other ones too.
I bought one and it works great.
New in the box, never opened.
The only thing wrong was the 4 base mounting screws were too short (no big 
deal).
They are on Ebay  # 282851759313.
$48.00 shipped.
Thanks,
Don W9BHI

Sent from Mail for Windows 10

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Re: [time-nuts] GPS Antenna Feed Line Decision

[Bob kb8tq]

Hi

> On Sep 5, 2017, at 5:19 PM, Charles Steinmetz  wrote:
> 
> Mike wrote:
> 
>> I tried to see if there was any difference in the signal quality reported by 
>> Motorola UT+ and U-Blox Neo 6M (not timing grade but has a good 1PPS) over 
>> 30m of 2 different cable types.
>> I only had RG58(75 Ohm) and RG174(50 Ohm).
> 
> RG58 is 50 ohm.  RG59 is the "equivalent" 75-ohm cable.
> 
> Also, there has been some discussion of internal reflections with mixed 
> source/cable/load impedances.  Yeah, there is some, BUT:  The reflections are 
> generated at the *interfaces* between impedances, not down the length of any 
> one cable.  "F" connectors are 75 ohms, so if any part of the system uses 
> them, they will generate approximately the same reflections at the interfaces 
> to 50 ohm components (cable impedance and impedance of source and/or load) as 
> would using 75 ohm cable.
> 
> To eliminate reflections "entirely" (in reality, "mostly"), you need to use 
> 50 ohm [or 75, or other] components exclusively (source and load Z, all 
> connectors, and cable).
> 
> Yeah, I could pull my Tbolts apart and replace the F connectors with SMA, 
> BNC, TNC, N, UF, whatever.  But any degradation caused by using 75 ohm cable 
> and connectors is completely swamped by other errors in the system.  One of 
> my Tbolts runs with about 30 feet of RG6 quad, the other with about 150 feet 
> of the same, and all timing and positional solutions are indistinguishable 
> from a test mule I cobbled together that used only an adapter (about an inch 
> and a half long) between the antenna and the Tbolt.  In that case, the 
> "cable" delay was so low that any reflections were time-displaced from the 
> direct signal by such a small amount that it was meaningless for all 
> practical purposes.

The next “bump” is the input impedance of the receiver. If you dig into it, 
receivers front ends rarely have 
good return loss numbers. There are a number of reasons for this. One is that a 
“mismatched” front end is
usually a lower noise solution.  If the front end is 103 -123J ohms, 75 ohm vs 
50 ohm cable is not the big 
issue. To a lesser extent, the same thing may apply to the antenna preamp 
output ….

Bob


> 
> Best regards,
> 
> Charles
> 
> 
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Re: [time-nuts] GPS Antenna Feed Line Decision

[Charles Steinmetz]

Mike wrote:


I tried to see if there was any difference in the signal quality reported by 
Motorola UT+ and U-Blox Neo 6M (not timing grade but has a good 1PPS) over 30m 
of 2 different cable types.
I only had RG58(75 Ohm) and RG174(50 Ohm).


RG58 is 50 ohm.  RG59 is the "equivalent" 75-ohm cable.

Also, there has been some discussion of internal reflections with mixed 
source/cable/load impedances.  Yeah, there is some, BUT:  The 
reflections are generated at the *interfaces* between impedances, not 
down the length of any one cable.  "F" connectors are 75 ohms, so if any 
part of the system uses them, they will generate approximately the same 
reflections at the interfaces to 50 ohm components (cable impedance and 
impedance of source and/or load) as would using 75 ohm cable.


To eliminate reflections "entirely" (in reality, "mostly"), you need to 
use 50 ohm [or 75, or other] components exclusively (source and load Z, 
all connectors, and cable).


Yeah, I could pull my Tbolts apart and replace the F connectors with 
SMA, BNC, TNC, N, UF, whatever.  But any degradation caused by using 75 
ohm cable and connectors is completely swamped by other errors in the 
system.  One of my Tbolts runs with about 30 feet of RG6 quad, the other 
with about 150 feet of the same, and all timing and positional solutions 
are indistinguishable from a test mule I cobbled together that used only 
an adapter (about an inch and a half long) between the antenna and the 
Tbolt.  In that case, the "cable" delay was so low that any reflections 
were time-displaced from the direct signal by such a small amount that 
it was meaningless for all practical purposes.


Best regards,

Charles


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Re: [time-nuts] GPS Antenna Feed Line Decision

[Mike Cook]

> Le 5 sept. 2017 à 16:17, Bob kb8tq  a écrit :
> 
> Hi
> 
> 
> 
>> On Sep 5, 2017, at 6:06 AM, Hal Murray  wrote:
>> 
>> 
>> Clay Autery  said:
>>> I will use something better than RG-59 or RG-6 (even if it is only "better"
>>> in my opinion).
>> 
>> Crazy thought department.  Can you also run a parallel run of RG-6 and run 
>> some tests to see if you can measure the difference?
> 
> There is pretty much no experiment you could run that would show a difference 
> between the two. With a normal GPS, the “front end” of the radio is in the 
> antenna. The
> filtering and RF amplification there determine a lot of things. The cable is 
> just a 
> chunk of wire in the middle of the system. 

Agreed.
I tried to see if there was any difference in the signal quality reported by 
Motorola UT+ and U-Blox Neo 6M (not timing grade but has a good 1PPS) over 30m 
of 2 different cable types.
I only had RG58(75 Ohm) and RG174(50 Ohm) . I used the signal quality graphics 
of the respective manufacturers utilities winoncore12 and u-center. There was 
very little visible difference in the levels and reported resolved positions 
were as in the same ball park ( I never get exact replication after surveys ). 
Neither was there any significant difference in the 1PPS signal. I only have a 
2 channel scope so had to measure each seperateley against a standard (PRS10). 
The receivers 1PPS quantization swamps the difference in the cable delay (which 
I was able to differentiate when measured separately). 
It make sense as the GPS signals are very weak and the receivers are good at 
getting data out, so just throwing in a bit of extra attenuation and noise 
doesn’t phase them at all. 

I was thinking of doing a test with just a twisted pair…. 


> 
> Bob
> 
> 
>> 
>> 
>> -- 
>> These are my opinions.  I hate spam.
>> 
>> 
>> 
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"The power of accurate observation is commonly called cynicism by those who 
have not got it. »
George Bernard Shaw

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Re: [time-nuts] GPS Antenna Feed Line Decision

[Bob kb8tq]

Hi



> On Sep 5, 2017, at 6:06 AM, Hal Murray  wrote:
> 
> 
> Clay Autery  said:
>> I will use something better than RG-59 or RG-6 (even if it is only "better"
>> in my opinion).
> 
> Crazy thought department.  Can you also run a parallel run of RG-6 and run 
> some tests to see if you can measure the difference?

There is pretty much no experiment you could run that would show a difference 
between the two. With a normal GPS, the “front end” of the radio is in the 
antenna. The
filtering and RF amplification there determine a lot of things. The cable is 
just a 
chunk of wire in the middle of the system. 

Bob


> 
> 
> -- 
> These are my opinions.  I hate spam.
> 
> 
> 
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Re: [time-nuts] GPS Antenna Feed Line Decision

[Hal Murray]

Clay Autery  said:
> I will use something better than RG-59 or RG-6 (even if it is only "better"
> in my opinion).

Crazy thought department.  Can you also run a parallel run of RG-6 and run 
some tests to see if you can measure the difference?


-- 
These are my opinions.  I hate spam.



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Re: [time-nuts] GPS Antenna Feed Line Decision

[Wes]

I'm dating myself again but when I was employed at Hughes Aircraft we had an HP 
salesman dedicated to servicing just us.  So most everything came direct from 
them or Wiltron.  I liked traveling to HP events with him.  Hughes had a miserly 
expense reporting process.  His was, "I count the money in my wallet before I 
leave.  I count it again when I get back.  The difference is my expense."


Wes

.  On 9/4/2017 2:26 PM, Bob kb8tq wrote:

Hi

A lot depends on just which outfit you buy your attenuators from. There
certainly *are* outfits out there that supply you just over 20 db RL when
the spec is 20. They also don’t charge very much for their attenuators ….

Bob



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Re: [time-nuts] GPS Antenna Feed Line Decision

[Bob kb8tq]

Hi

A lot depends on just which outfit you buy your attenuators from. There 
certainly *are* outfits out there that supply you just over 20 db RL when
the spec is 20. They also don’t charge very much for their attenuators ….

Bob

> On Sep 4, 2017, at 4:53 PM, jimlux  wrote:
> 
> On 9/4/17 1:18 PM, Wes wrote:
>> 
>> 
>> If these are COTS attenuators, their own return loss is unlikely to be
>> 40 dB.  In fact grabbing an old HP catalog off my bookshelf (I'm dating
>> myself) I see a typical type N attenuator specified as 1.2 VSWR (~21 dB
>> RL).  I went on a quick "shopping" trip looking for an L-band, type N
>> bias tee.  I'll spare you the links, but typically they are also rated
>> at 1.2 VSWR.
>> 
> 
> Be careful, that's the "catalog spec" which means "what we can inexpensively 
> measure"..
> 
> It's like SMA connectors, which are specified at 1.05:1 or 1.1:1 and <0.3dB 
> loss.
> https://www.amphenolrf.com/connectors/sma.html
> 
> 
> In reality, they are a LOT better, it's just that measuring that in a 
> production environment is tough.
> I'd not want to set up a manufacturing test set that measured loss with an 
> uncertainty of 0.01 dB.
> 
> I'll point folks to:
> Jesch's paper in 1976
> 
> http://ieeexplore.ieee.org/document/6312234/
> 
> 
> 
> and then Maury
> https://www.maurymw.com/pdf/datasheets/5A-021.pdf
> 
> Someone at Maury did a paper which I can't find right now where they measured 
> a bunch of SMA connectors over hundreds if not thousands of mate/demate 
> cycles.
> 
> 
> RF cafe has a nice summary
> http://www.rfcafe.com/references/articles/Joe-Cahak/rf-connectors-cables-joe-cahak-6-2014.htm
> 
> 
> 
> 
> 
> 
>> Perhaps NIST, with an unlimited supply of tax money, splurged and
>> manufactured bias tees with >40 dB RL.  Maybe they did the same with the
>> attenuators.  We'll never know because they didn't provide an equipment
>> list or a measurement procedure.  They said nothing about the cable
>> either, other than they started with RG-58 and replaced it with "better"
>> cable.
> 
> But you could probably send an email to the author and ask.  NIST, like JPL, 
> is one of those places where people work forever.  Tom Otoshi, who wrote a 
> report on N connectors in 1963 cited by Maury, above, still works at JPL (I 
> think.. I confess I haven't seen him recently, he might have retired, but he 
> was certainly around in the last 10 years), and given the span of years, that 
> N connector work was probably when he was a just out of school engineer.
> 
> 
> 
> 
> 
> 
> 
>> 
>> A few words about cable, since that is what this discussion is all
>> about.  Cable, regardless of type and manufacturer, has its own RL, also
>> known in that business as Structural Return Loss (SRL) See:
>> https://www.belden.com/docs/upload/hdcarltp.pdf and
>> http://www.keysight.com/upload/cmc_upload/All/E206COMPTEST_METHOD.pdf.
>> 
>> At least the authors admit, "Thus far we have seen little difference in
>> the data."
>> 
>> Wes
>> 
>> 
>> On 9/3/2017 3:02 PM, Bill Byrom wrote:
>>> For precision timing measurements, I would think that there would be
>>> concern about the double reflections of a badly mismatched low loss
>>> transmission line (such as using 75 ohm line in a 50 ohm environment).
>>> The re-reflected signal will act similar to  multipath (as a delayed
>>> aggressor) on all satellite signals equally. The impedance mismatch
>>> delayed reflection aggressor could aggravate timing errors due to
>>> changes in temperature or stress in the cable. Whether this is important
>>> for you depends on how time-nutty you want to get.
>>> 
>>> See these papers:
>>> 
>>> Effects of Antenna Cables on GPS Timing Receivers:
>>> http://tf.boulder.nist.gov/general/pdf/1384.pdf
>>> 
>>> Absolute Calibration of a Geodetic Time Transfer System:
>>> http://xenon.colorado.edu/paperIrevise2.pdf
>>> --
>>> Bill Byrom N5BB
>>> 
>> 
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Re: [time-nuts] GPS Antenna Feed Line Decision

[jimlux]

On 9/4/17 1:18 PM, Wes wrote:



If these are COTS attenuators, their own return loss is unlikely to be
40 dB.  In fact grabbing an old HP catalog off my bookshelf (I'm dating
myself) I see a typical type N attenuator specified as 1.2 VSWR (~21 dB
RL).  I went on a quick "shopping" trip looking for an L-band, type N
bias tee.  I'll spare you the links, but typically they are also rated
at 1.2 VSWR.



Be careful, that's the "catalog spec" which means "what we can 
inexpensively measure"..


It's like SMA connectors, which are specified at 1.05:1 or 1.1:1 and 
<0.3dB loss.

https://www.amphenolrf.com/connectors/sma.html


In reality, they are a LOT better, it's just that measuring that in a 
production environment is tough.
I'd not want to set up a manufacturing test set that measured loss with 
an uncertainty of 0.01 dB.


I'll point folks to:
Jesch's paper in 1976

http://ieeexplore.ieee.org/document/6312234/



and then Maury
https://www.maurymw.com/pdf/datasheets/5A-021.pdf

Someone at Maury did a paper which I can't find right now where they 
measured a bunch of SMA connectors over hundreds if not thousands of 
mate/demate cycles.



RF cafe has a nice summary
http://www.rfcafe.com/references/articles/Joe-Cahak/rf-connectors-cables-joe-cahak-6-2014.htm







Perhaps NIST, with an unlimited supply of tax money, splurged and
manufactured bias tees with >40 dB RL.  Maybe they did the same with the
attenuators.  We'll never know because they didn't provide an equipment
list or a measurement procedure.  They said nothing about the cable
either, other than they started with RG-58 and replaced it with "better"
cable.


But you could probably send an email to the author and ask.  NIST, like 
JPL, is one of those places where people work forever.  Tom Otoshi, who 
wrote a report on N connectors in 1963 cited by Maury, above, still 
works at JPL (I think.. I confess I haven't seen him recently, he might 
have retired, but he was certainly around in the last 10 years), and 
given the span of years, that N connector work was probably when he was 
a just out of school engineer.










A few words about cable, since that is what this discussion is all
about.  Cable, regardless of type and manufacturer, has its own RL, also
known in that business as Structural Return Loss (SRL) See:
https://www.belden.com/docs/upload/hdcarltp.pdf and
http://www.keysight.com/upload/cmc_upload/All/E206COMPTEST_METHOD.pdf.

At least the authors admit, "Thus far we have seen little difference in
the data."

Wes


On 9/3/2017 3:02 PM, Bill Byrom wrote:

For precision timing measurements, I would think that there would be
concern about the double reflections of a badly mismatched low loss
transmission line (such as using 75 ohm line in a 50 ohm environment).
The re-reflected signal will act similar to  multipath (as a delayed
aggressor) on all satellite signals equally. The impedance mismatch
delayed reflection aggressor could aggravate timing errors due to
changes in temperature or stress in the cable. Whether this is important
for you depends on how time-nutty you want to get.

See these papers:

Effects of Antenna Cables on GPS Timing Receivers:
http://tf.boulder.nist.gov/general/pdf/1384.pdf

Absolute Calibration of a Geodetic Time Transfer System:
http://xenon.colorado.edu/paperIrevise2.pdf
--
Bill Byrom N5BB



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Re: [time-nuts] GPS Antenna Feed Line Decision

[Wes]

Not being as nutty as many on this list I only skimmed the papers you provided.  
Interesting and I will stand corrected regarding the use of 75 ohm cable in 50 
ohm systems in critical situations.  In situations like my own, I'm not going to 
fuss about it.


I realize this is NIST, the 1384 paper was probably peer-reviewed, and I 
shouldn't question, nevertheless fools rush in.


In the block diagram of Figure 3 and the accompanying text, is described 
installing attenuators to increase return loss (RL) to what is claimed to be 40 
dB.  Forty dB RL is in the realm of precision calibration standards. 
(https://www.maurymw.com/Precision/Precision_Fixed_Terminations.php) and it's 
not trivial to measure on a single device.  Here we have a cascaded of two 
attenuators, two bias tees and a length of cable.


If these are COTS attenuators, their own return loss is unlikely to be 40 dB.  
In fact grabbing an old HP catalog off my bookshelf (I'm dating myself) I see a 
typical type N attenuator specified as 1.2 VSWR (~21 dB RL).  I went on a quick 
"shopping" trip looking for an L-band, type N bias tee.  I'll spare you the 
links, but typically they are also rated at 1.2 VSWR.


Perhaps NIST, with an unlimited supply of tax money, splurged and manufactured 
bias tees with >40 dB RL.  Maybe they did the same with the attenuators.  We'll 
never know because they didn't provide an equipment list or a measurement 
procedure.  They said nothing about the cable either, other than they started 
with RG-58 and replaced it with "better" cable.


A few words about cable, since that is what this discussion is all about.  
Cable, regardless of type and manufacturer, has its own RL, also known in that 
business as Structural Return Loss (SRL) See: 
https://www.belden.com/docs/upload/hdcarltp.pdf and 
http://www.keysight.com/upload/cmc_upload/All/E206COMPTEST_METHOD.pdf.


At least the authors admit, "Thus far we have seen little difference in the 
data."

Wes


On 9/3/2017 3:02 PM, Bill Byrom wrote:

For precision timing measurements, I would think that there would be
concern about the double reflections of a badly mismatched low loss
transmission line (such as using 75 ohm line in a 50 ohm environment).
The re-reflected signal will act similar to  multipath (as a delayed
aggressor) on all satellite signals equally. The impedance mismatch
delayed reflection aggressor could aggravate timing errors due to
changes in temperature or stress in the cable. Whether this is important
for you depends on how time-nutty you want to get.

See these papers:

Effects of Antenna Cables on GPS Timing Receivers:
http://tf.boulder.nist.gov/general/pdf/1384.pdf

Absolute Calibration of a Geodetic Time Transfer System:
http://xenon.colorado.edu/paperIrevise2.pdf
--
Bill Byrom N5BB



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Re: [time-nuts] GPS Antenna Feed Line Decision

[Mark Spencer]

Although not time nuts related I believe this document speaks to some of the 
practical issues...

http://www.slac.stanford.edu/cgi-wrap/getdoc/slac-pub-6297.pdf



Mark Spencer


m...@alignedsolutions.com

> On Sep 3, 2017, at 4:56 PM, Mark Sims  wrote:
> 
> Real time nuts run phase stable cable (some well over $50 / foot) in climate 
> controlled ducts... which is all for nought unless you also climate control 
> the antenna.Which is all standard practice for precision geodesy.  Try to 
> keep it all with a milli-Kelvin or two.  Oh, and don't forget about Lord 
> Kelvin's sinister  step-sisters, humidity and pressure.  We won't get into 
> all his second-order cousins.
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[time-nuts] GPS Antenna Feed Line Decision

[Mark Sims]

Real time nuts run phase stable cable (some well over $50 / foot) in climate 
controlled ducts... which is all for nought unless you also climate control the 
antenna.Which is all standard practice for precision geodesy.  Try to keep 
it all with a milli-Kelvin or two.  Oh, and don't forget about Lord Kelvin's 
sinister  step-sisters, humidity and pressure.  We won't get into all his 
second-order cousins.
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Re: [time-nuts] GPS Antenna Feed Line Decision

[Bob kb8tq]

Hi

If you are running into a TBolt, it’s got an F connector and 75 ohm cable
spec’d already …. The 50 ohm / 75 ohm thing didn’t seem to bother 
Trimble. They certainly looked at it before going that way ….

Bob

> On Sep 4, 2017, at 12:31 AM, Ian Stirling  wrote:
> 
> On 09/02/2017 02:57 PM, Clay Autery wrote:
>> Having decision-making problems for the materials for my GPS main
>> feedline.  Going to use a TM LMR stock, just can't decide how big to go
>> with it...
> 
>  I have a modest 26dB antenna on a six feet pole of plastic piping, the 
> piping is
> strapped to my deck post. The antenna is probably ten feet high added to my 
> deck.
> I use a 40' RG6 that my Comcast chap overestimated, and he said, "Just use it 
> as you need."
> I measured the theoretical 1.4 SWR with as pretty much dead on. So long as my 
> GPS boxes
> agree with consumer time, as measured by the cheap "atomic" clocks from super 
> cheap vendors,
> I am happy with the set up. I have no need of phase and jitter, so long as 
> they average out.
> 
>  I just had to buy some "F" connectors and use adapters to convert to the GPS 
> 50 ohm inputs.
> Works like a charm. And good enough for me.
> 
> Best wishes,
> Ian, G4ICV, AB2GR
> --
> 
> 
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Re: [time-nuts] GPS Antenna Feed Line Decision

[Ian Stirling]

On 09/02/2017 02:57 PM, Clay Autery wrote:
> Having decision-making problems for the materials for my GPS main
> feedline.  Going to use a TM LMR stock, just can't decide how big to go
> with it...

  I have a modest 26dB antenna on a six feet pole of plastic piping, the piping 
is
strapped to my deck post. The antenna is probably ten feet high added to my 
deck.
I use a 40' RG6 that my Comcast chap overestimated, and he said, "Just use it 
as you need."
I measured the theoretical 1.4 SWR with as pretty much dead on. So long as my 
GPS boxes
agree with consumer time, as measured by the cheap "atomic" clocks from super 
cheap vendors,
I am happy with the set up. I have no need of phase and jitter, so long as they 
average out.

  I just had to buy some "F" connectors and use adapters to convert to the GPS 
50 ohm inputs.
Works like a charm. And good enough for me.

Best wishes,
Ian, G4ICV, AB2GR
--


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Re: [time-nuts] GPS Antenna Feed Line Decision

[jimlux]

On 9/3/17 3:41 PM, Charles Steinmetz wrote:

Attila wrote:


The supplies for LNAs are usually quite benign given two constraints:
   *   *   *
1) Low frequency (0Hz to bandwidth of signal) noise is low
   *   *   *
But 1) is a bit harder as it also includes 1/f noise, temperature,
(upstream) supply and load effects.


The LT3042 is better in this regard than anything short of a heroic
effort with discrete components, IF you use a larger-than-normal bypass
capacitor on the SET pin.  With Cset = 22uF, the noise density is
<20nV/sqrtHz down to 10Hz.  220uF is somewhat better, but not by a whole
decade because of the 1/f noise of the error/output amplifier.

The down side of a large Cset is that the power supply takes longer to
reach its final voltage.  A 5v supply reaches 90% voltage in about 25
seconds, and 99% in about 40 seconds.  A 10v supply takes twice as long,
and a 15v supply, three times.  The LT3042 does have a "fast start"
mode, which can reduce these times considerably (to ~0.5sec, ~1sec, and
~1.5sec, respectively) -- but still longer than usual for a regulated
supply.  For applications like continuously-on LNA power, there should
be no problem with any of these times.

The LT3042 is a bit of a pain to use, with its buried ground/heatsink
tab, but it is very good, and is the lowest noise fully integrated
regulator available, AFAIK.


I love that part - the PSRR is awesome up to MHz.  So many of those 
linear regulators are great at kHz, but not so hot up higher.

You want quiet, the 3042 is your friend.

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Re: [time-nuts] GPS Antenna Feed Line Decision

[Glenn Little WB4UIV]

I work with a broadcast station.
We just had a HD FM radio transmitter upgrade done.
In the upgrade package from GatesAir was a GPS antenna with a F fitting.
The provided feedline was RG-223 with a TNC on one end and a SMA on the 
other.

Also provided was a TNC to F adapter.
The new exciter has a GPS receiver installed to provide 1 PPS to the 
exciter.
There was also another piece of equipment that required 1 PPS and they 
provided an antenna and no feedline with that one.

Either piece would output 1 PPS, so the second antenna was not needed.

So you wonder what the "professionals" had in mind with the adapters.
Low bidder for the antenna??

73
Glenn
WB4UIV

On 9/3/2017 10:09 AM, Wes wrote:

On 9/2/2017 4:48 PM, Clay Autery wrote:

Thanks for the response...

Not sure why you and the other guy both recommended RG-6 75-Ohm cable
and F-connectors, when the nominal impedance of literally everything
else in the system is 50 Ohm, including the antenna and the HP GPS
Distribution Amp  And then adding N to F adapters?
As "the other guy" (I think) let me say that the impedance mismatch is 
immaterial and in my case I have one GPSDO with an SMA connector and 
another with a BNC and an antenna with an SMA.  So I "adapt" no matter 
what I do.  Because I understand the cascaded noise figure equations, 
I know that I don't need an active distribution amplifier to feed just 
these two devices, so a $5.00 "F" connector splitter is adequate. 
(https://www.markertek.com/product/201-232/2-way-2-4ghz-90db-satellite-splitter-dc-power-passing-to-one-port)

Doesn't make any sense unless one has $$ as a top priority, already has
a spool of RG-6 quad shield, etc...  but I specifically stated that $$
is not a top priority  Not really even in the top 5 or 10...

Then by all means you should use L-band waveguide. :-)

Wes

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--
---
Glenn LittleARRL Technical Specialist   QCWA  LM 28417
Amateur Callsign:  WB4UIVwb4...@arrl.netAMSAT LM 2178
QTH:  Goose Creek, SC USA (EM92xx)  USSVI LM   NRA LM   SBE ARRL TAPR
"It is not the class of license that the Amateur holds but the class
of the Amateur that holds the license"
---

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Re: [time-nuts] GPS Antenna Feed Line Decision

[Richard Solomon]

One of my "Hockey Puck" antennas has about 50' of RG-174 on it and I have

seen no problems locking up.


73, Dick, W1KSZ


Sent from Outlook<http://aka.ms/weboutlook>

From: time-nuts  on behalf of William H. Fite 

Sent: Saturday, September 2, 2017 9:33:09 PM
To: Discussion of precise time and frequency measurement
Subject: Re: [time-nuts] GPS Antenna Feed Line Decision

True, though a friend of mine used LMR-400.


On Saturday, September 2, 2017, Mark Sims  wrote:

> Cheap RG-59 cable coax is more than sufficient for 50 .. 150+ feet (unless
> you are doing geodetic level GPS work).  It is recommended by several GPSDO
> makers.  The 50/75 ohm mismatch is not an issue.  No need to waste money on
> fancy pants artisanal luxury coax.
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talent.
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Re: [time-nuts] GPS Antenna Feed Line Decision

[Charles Steinmetz]

Attila wrote:


The supplies for LNAs are usually quite benign given two constraints:
   *   *   *
1) Low frequency (0Hz to bandwidth of signal) noise is low
   *   *   *
But 1) is a bit harder as it also includes 1/f noise, temperature,
(upstream) supply and load effects.


The LT3042 is better in this regard than anything short of a heroic 
effort with discrete components, IF you use a larger-than-normal bypass 
capacitor on the SET pin.  With Cset = 22uF, the noise density is 
<20nV/sqrtHz down to 10Hz.  220uF is somewhat better, but not by a whole 
decade because of the 1/f noise of the error/output amplifier.


The down side of a large Cset is that the power supply takes longer to 
reach its final voltage.  A 5v supply reaches 90% voltage in about 25 
seconds, and 99% in about 40 seconds.  A 10v supply takes twice as long, 
and a 15v supply, three times.  The LT3042 does have a "fast start" 
mode, which can reduce these times considerably (to ~0.5sec, ~1sec, and 
~1.5sec, respectively) -- but still longer than usual for a regulated 
supply.  For applications like continuously-on LNA power, there should 
be no problem with any of these times.


The LT3042 is a bit of a pain to use, with its buried ground/heatsink 
tab, but it is very good, and is the lowest noise fully integrated 
regulator available, AFAIK.


Best regards,

Charles


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Re: [time-nuts] GPS Antenna Feed Line Decision

[Mike Naruta AA8K]

On 09/03/2017 06:02 PM, Bill Byrom wrote:

For precision timing measurements, I would think that there would be
concern about the double reflections of a badly mismatched low loss
transmission line (such as using 75 ohm line in a 50 ohm environment).
The re-reflected signal will act similar to  multipath (as a delayed
aggressor) on all satellite signals equally. The impedance mismatch
delayed reflection aggressor could aggravate timing errors due to
changes in temperature or stress in the cable. Whether this is important
for you depends on how time-nutty you want to get.

See these papers:

Effects of Antenna Cables on GPS Timing Receivers:
http://tf.boulder.nist.gov/general/pdf/1384.pdf

Absolute Calibration of a Geodetic Time Transfer System:
http://xenon.colorado.edu/paperIrevise2.pdf
--
Bill Byrom N5BB




Thank you Bill, very interesting.


Wes, that waveguide is looking better all the time.

It will be difficult to control the temperature of it though.


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Re: [time-nuts] GPS Antenna Feed Line Decision

[Bill Byrom]

For precision timing measurements, I would think that there would be
concern about the double reflections of a badly mismatched low loss
transmission line (such as using 75 ohm line in a 50 ohm environment).
The re-reflected signal will act similar to  multipath (as a delayed
aggressor) on all satellite signals equally. The impedance mismatch
delayed reflection aggressor could aggravate timing errors due to
changes in temperature or stress in the cable. Whether this is important
for you depends on how time-nutty you want to get.

See these papers:

Effects of Antenna Cables on GPS Timing Receivers:
http://tf.boulder.nist.gov/general/pdf/1384.pdf

Absolute Calibration of a Geodetic Time Transfer System:
http://xenon.colorado.edu/paperIrevise2.pdf
--
Bill Byrom N5BB


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Re: [time-nuts] GPS Antenna Feed Line Decision

[Attila Kinali]

On Sun, 3 Sep 2017 12:32:31 -0500
Clay Autery  wrote:

> - I saw in some aviation references where pilots claimed that they
> achieved "better performance" by running their antennas at higher
> voltages.  (Overclocking the antenna amp?  Who knows.)  But it piqued my
> interest, especially since the PCTEL antenna I have will "run" from
> below 5VDC through 12 VDC and has an even higher survival voltage.

There are a couple of LNA chips around that work at 3.3V and 5V.
Usually they exhibit better performance (higher amplification and
less degradation with frequency) with higher voltage. You should
not run those chips at higher voltage then spec'ed, though.

An antenna with a 5V-12V rating has most likely a local LDO, thus
it will not benefit from higher voltage, beside having more heat
generated localy, which might or might not stabilize temperature.

> Bottom Line: I'll read/research/design and build until I come up with a
> supply that meets my needs.  Just off the top of my head, a linear
> supply that charges a battery or batteries that provide the top voltage
> or voltages in multiple ranges which are then regulated/filtered to
> provide dead flat DC at the desired levels.
> I am not an engineer or an expert of any kind.  I'll have to go learn
> all this.  

The supplies for LNAs are usually quite benign given two constraints:
1) Low frequency (0Hz to bandwidth of signal) noise is low
2) High frequency noise within the signal range is low.

It is usually quite easy to achieve 2) by using some L-C filter.
But 1) is a bit harder as it also includes 1/f noise, temperature,
(upstream) supply and load effects. 


Attila Kinali

-- 
You know, the very powerful and the very stupid have one thing in common.
They don't alters their views to fit the facts, they alter the facts to
fit the views, which can be uncomfortable if you happen to be one of the
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Re: [time-nuts] GPS Antenna Feed Line Decision

[Mark Spencer]

Hi.

The last time I looked at upgrading my GPS antenna feed line (I'm currently 
using RG58 style cable) I spent some time looking at the temperature vs 
propagation delay characteristics of various cables.

I also picked up a spool of cloned "LMR400 style" cable but ended up using that 
for my amateur radio hobby.  If I was going to throw more money at my Time Nuts 
GPS feed line I'd probably look for a "hard line" style cable with a favourable 
temperature vs propagation delay characteristic.   For a basic installation I 
expect I would just use RG6 style cable.

Good luck.

Mark S

m...@alignedsolutions.com
604 762 4099

> On Sep 3, 2017, at 9:57 AM, Clay Autery  wrote:
> 
> Thank you for your response.  Again, money is not the issue or
> priority.  Knowing that I am getting the best signal within reason (my
> reason   )
> Tangentially, you have provided me with the information I require.  As I
> do not know what I will hang off the end of that antenna in the future
> and I am in fact going to be doing some measurement/experimentation, I
> will use something better than RG-59 or RG-6 (even if it is only
> "better" in my opinion).
> 
> I am an incurable over-engineer... and this IS "Time NUTS" after all. 
> 
> 
> Thank to you AND to ALL who have made recommendations thusfar
> especially the ones with whom I disagree.  Those are the recommendations
> that keep me from completely abandoning rational decision-making.   grin>
> 
> 73,
> 
> __
> Clay Autery, KY5G
> MONTAC Enterprises
> (318) 518-1389
> 
>> On 9/2/2017 3:27 PM, Mark Sims wrote:
>> Cheap RG-59 cable coax is more than sufficient for 50 .. 150+ feet (unless 
>> you are doing geodetic level GPS work).  It is recommended by several GPSDO 
>> makers.  The 50/75 ohm mismatch is not an issue.  No need to waste money on 
>> fancy pants artisanal luxury coax.
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Re: [time-nuts] GPS Antenna Feed Line Decision

[Clay Autery]

Thank you for your response.  Again, money is not the issue or
priority.  Knowing that I am getting the best signal within reason (my
reason   )
Tangentially, you have provided me with the information I require.  As I
do not know what I will hang off the end of that antenna in the future
and I am in fact going to be doing some measurement/experimentation, I
will use something better than RG-59 or RG-6 (even if it is only
"better" in my opinion).

I am an incurable over-engineer... and this IS "Time NUTS" after all. 


Thank to you AND to ALL who have made recommendations thusfar
especially the ones with whom I disagree.  Those are the recommendations
that keep me from completely abandoning rational decision-making.  

73,

__
Clay Autery, KY5G
MONTAC Enterprises
(318) 518-1389

On 9/2/2017 3:27 PM, Mark Sims wrote:
> Cheap RG-59 cable coax is more than sufficient for 50 .. 150+ feet (unless 
> you are doing geodetic level GPS work).  It is recommended by several GPSDO 
> makers.  The 50/75 ohm mismatch is not an issue.  No need to waste money on 
> fancy pants artisanal luxury coax.
>
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Re: [time-nuts] GPS Antenna Feed Line Decision

[Clay Autery]

Actually haven't settled on an exact solution yet, Gilles.  The power
supply will likely become part of the observations/experiment that
prompted me to use the external supply in the first place.

- All of the devices WANT to supply the antenna.  2 are nominal 5VDC, 1
supplies nominal 3.3VDC...  so I was going to have to use DC blocking
anyway.  The HP amp provides a load resistor (to fool the devices
hopefully) and DC blocking on all ports.  Thus, I get to choose how I
provide the DC power to the PCTEL antenna.

- I saw in some aviation references where pilots claimed that they
achieved "better performance" by running their antennas at higher
voltages.  (Overclocking the antenna amp?  Who knows.)  But it piqued my
interest, especially since the PCTEL antenna I have will "run" from
below 5VDC through 12 VDC and has an even higher survival voltage.

Thus was born the secondary goal of finding out if there is anything to
these reports.  IF I can control the voltage supplied on a (preferably
constant) variable basis to the antenna, I can construct an experiment
to evaluate IF there are performance increase/degradation and in what
ways  over a wide range of voltages.  IF it pans out on MY antenna,
I will likely have to expand it to additional antennas.

BUT, in answer to your direct question:  Right now I do not know.  I do
know a FEW things.

1) It certainly will not be a switching PS.
2) While I would love to use a super-expensive "lab-grade" supply, I
would actually like to engineer a solution that I can integrate into the
shack/lab on a permanent basis for use in normal ops and future projects.
3) I'm leaning in the same direction that I am for powering everything
in my house that actually wants DC current  some combination of
linear power supplies and batteries.
4) A lot of this is simply an excuse to engage in an academic exercise
in order to learn/play.  

Bottom Line: I'll read/research/design and build until I come up with a
supply that meets my needs.  Just off the top of my head, a linear
supply that charges a battery or batteries that provide the top voltage
or voltages in multiple ranges which are then regulated/filtered to
provide dead flat DC at the desired levels.
I am not an engineer or an expert of any kind.  I'll have to go learn
all this.  

73,

__
Clay Autery, KY5G

On 9/3/2017 1:55 AM, Clemgill wrote:
> Hi Clay,
> Intersting subject.
> What design for ultra stable/clean power supply are you using please ?
> Thx,
> Gilles.
>
>> On Sep 2, 2017, at 22:47, Clay Autery  wrote:
>>
>> PCTEL GPS-TMG-HR-26NCM Antenna. 
>> http://www.neobits.com/pctel_maxrad_gps_tmg_hr_26ncm_high_rejection_gps_p2769137.htm
>>
>> Can't say what the gain tolerances are, but it appears to be a pretty
>> decent quality part.
>>
>> The distribution amp is an HP 58516A GPS L1 Distribution Amp with the
>> external power supply tap which will be fed with an ultras stable/clean
>> adjustable linear power supply.  As I understand it, this is a unity
>> gain amp, so there should be little to no insertion loss or distro losses.
>>
>> The distribution amp will be mounted near the devices such that amp to
>> device jumpers will all be < 1 meter/3.28 feet.  Likely a lot less.  ALL
>> Times N-connectors until reaching a connector TM doesn't make.
>>
>> __
>> Clay Autery, KY5G
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Re: [time-nuts] GPS Antenna Feed Line Decision

[Bob kb8tq]

Hi

The bigger issue with unsuspended cables is wind and weather. It’s not just a 
static weight issue.
When the wind blows the cable jerks around. You very much want to tie it off 
against the mast. You
also want a strain relief loop at the antenna. 

Bob


> On Sep 3, 2017, at 10:44 AM, Artek Manuals  wrote:
> 
> Clay
> LMR-400 is probably the best compromise , I doubt you will see any useful 
> improvement in system performance as a result of the improved 1.5db loss 
> characteristics of the larger cables. Losses due to atmospherics, 
> ionospherics and multi-path will be an orders of magnitude  higher than the 
> additional 1.5 db of signal improvement with the larger cables. We are not 
> talking comms with some guy in a space suit on Mars here :-)
> 
> AS for walking the mast  up I have done a number of installations of this 
> sort and the use of a block and tackle at the eve point is not difficult, and 
> will be appreciated more and more the older you get .  Mechanical 
> multiplicative advantages are easy to implement. Don't use block & tackles 
> which can pivot since depending on the weave/braid of the rope they will 
> twist around and bind.
> 
> Dave
> manu...@artekmanuals.com
> 
> On 9/2/2017 7:48 PM, Clay Autery wrote:
>> Thanks for the response...
>> 
>> Not sure why you and the other guy both recommended RG-6 75-Ohm cable
>> and F-connectors, when the nominal impedance of literally everything
>> else in the system is 50 Ohm, including the antenna and the HP GPS
>> Distribution Amp  And then adding N to F adapters?
>> 
>> Doesn't make any sense unless one has $$ as a top priority, already has
>> a spool of RG-6 quad shield, etc...  but I specifically stated that $$
>> is not a top priority  Not really even in the top 5 or 10...
>> 
>> The whole point of this exercise is to put up a semi-permanent SINGLE
>> antenna/feed-line install that will supply all 4 ports of the HP amp
>> with the least compromised signal within reason 4 now, and 8
>> whenever I can find the HP 8-way distro amp with external power input.
>> 
>> Strain relief solution:  Really depends upon which cable stock I end up
>> using  Obviously, the larger the cable, the more weight will be
>> suspended under the antenna (approx. 38 feet, depending on where I pull
>> the cable out of the mast at the bottom.  (The mast is on a tilt-base of
>> my own construction  which brings up a valid consideration.  it is
>> already a chore to walk the mast up manually.  The more weight added at
>> the top and inside the mast, the more difficult a manual walk-up will
>> be.  I'd prefer to keep this a manual tilt for now...  at least until I
>> add the tri-band vertical dipole)
>> 
>> LMR-400 would be less than 4 lbs total weight...  I'd likely suspend the
>> cable by the connector alone. (although, it wouldn't be JUST the
>> crimp...  The connector would have at a minimum, 1 layer of
>> adhesive-lined shrink tube... probably 2, with the second, overlapping.
>> Then a nice wrap of self-fusing tape and then electrical tape over that.
>> Even LMR-600 could be suspended by the connector alone, at 5 lbs max in
>> the 38 foot max vertical section.
>> I do have several methods of secondary suspension within the top (and/or
>> second) mast section though if I decide I need it.
>> 
>> Also prefer to keep all the connectors N-type as much as possible since
>> that is the station standard.
>> 
>> 73,
>> 
>> __
>> Clay Autery, KY5G
>> 
>> On 9/2/2017 6:07 PM, Mike Naruta AA8K wrote:
>>> Clay, you may wish to consider using a quality RG-6 with F
>>> connectors.  Grounding blocks are readily available for the base of
>>> your mast and the entrance to your house.  Also, off-the-shelf
>>> over-voltage protectors (Zap-Tech) are available. I even found an
>>> F-to-N adapter for the antenna on Amazon.  Watch out for the ones with
>>> metric N threads though.
>>> 
>>> For my 25 meter run I was going to use an existing one inch Heliax,
>>> but pulled a run of Belden RG-6 instead after learning that Trimble
>>> used RG-6.
>>> 
>>> It worked well directly connected to a Trimble Thunderbolt; now it is
>>> connected to a Symmetricon 58535A GPS L1 distribution amplifier.
>>> 
>>> 
>>> My Blitzortung System Red station has been running fine in my attic
>>> (Michigan) on a Motorola 97 Oncore patch antenna fastened against the
>>> roof underside.  It is looking through wood, shingles, and nails (and
>>> a tree and antennas and utility lines).
>>> 
>>> 
>>> How are you planning to do strain-relief on the vertical run of coax
>>> inside of your mast?
>>> 
>>> 
>>> Mike - AA8K
>>> 
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Re: [time-nuts] GPS Antenna Feed Line Decision

[Artek Manuals]

Clay
LMR-400 is probably the best compromise , I doubt you will see any 
useful improvement in system performance as a result of the improved 
1.5db loss characteristics of the larger cables. Losses due to 
atmospherics, ionospherics and multi-path will be an orders of 
magnitude  higher than the additional 1.5 db of signal improvement with 
the larger cables. We are not talking comms with some guy in a space 
suit on Mars here :-)


AS for walking the mast  up I have done a number of installations of 
this sort and the use of a block and tackle at the eve point is not 
difficult, and will be appreciated more and more the older you get .  
Mechanical multiplicative advantages are easy to implement. Don't use 
block & tackles which can pivot since depending on the weave/braid of 
the rope they will twist around and bind.


Dave
manu...@artekmanuals.com

On 9/2/2017 7:48 PM, Clay Autery wrote:

Thanks for the response...

Not sure why you and the other guy both recommended RG-6 75-Ohm cable
and F-connectors, when the nominal impedance of literally everything
else in the system is 50 Ohm, including the antenna and the HP GPS
Distribution Amp  And then adding N to F adapters?

Doesn't make any sense unless one has $$ as a top priority, already has
a spool of RG-6 quad shield, etc...  but I specifically stated that $$
is not a top priority  Not really even in the top 5 or 10...

The whole point of this exercise is to put up a semi-permanent SINGLE
antenna/feed-line install that will supply all 4 ports of the HP amp
with the least compromised signal within reason 4 now, and 8
whenever I can find the HP 8-way distro amp with external power input.

Strain relief solution:  Really depends upon which cable stock I end up
using  Obviously, the larger the cable, the more weight will be
suspended under the antenna (approx. 38 feet, depending on where I pull
the cable out of the mast at the bottom.  (The mast is on a tilt-base of
my own construction  which brings up a valid consideration.  it is
already a chore to walk the mast up manually.  The more weight added at
the top and inside the mast, the more difficult a manual walk-up will
be.  I'd prefer to keep this a manual tilt for now...  at least until I
add the tri-band vertical dipole)

LMR-400 would be less than 4 lbs total weight...  I'd likely suspend the
cable by the connector alone. (although, it wouldn't be JUST the
crimp...  The connector would have at a minimum, 1 layer of
adhesive-lined shrink tube... probably 2, with the second, overlapping.
Then a nice wrap of self-fusing tape and then electrical tape over that.
Even LMR-600 could be suspended by the connector alone, at 5 lbs max in
the 38 foot max vertical section.
I do have several methods of secondary suspension within the top (and/or
second) mast section though if I decide I need it.

Also prefer to keep all the connectors N-type as much as possible since
that is the station standard.

73,

__
Clay Autery, KY5G

On 9/2/2017 6:07 PM, Mike Naruta AA8K wrote:

Clay, you may wish to consider using a quality RG-6 with F
connectors.  Grounding blocks are readily available for the base of
your mast and the entrance to your house.  Also, off-the-shelf
over-voltage protectors (Zap-Tech) are available. I even found an
F-to-N adapter for the antenna on Amazon.  Watch out for the ones with
metric N threads though.

For my 25 meter run I was going to use an existing one inch Heliax,
but pulled a run of Belden RG-6 instead after learning that Trimble
used RG-6.

It worked well directly connected to a Trimble Thunderbolt; now it is
connected to a Symmetricon 58535A GPS L1 distribution amplifier.


My Blitzortung System Red station has been running fine in my attic
(Michigan) on a Motorola 97 Oncore patch antenna fastened against the
roof underside.  It is looking through wood, shingles, and nails (and
a tree and antennas and utility lines).


How are you planning to do strain-relief on the vertical run of coax
inside of your mast?


Mike - AA8K

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--
Dave
manu...@artekmanuals.com
www.ArtekManuals.com


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Re: [time-nuts] GPS Antenna Feed Line Decision

[Bob kb8tq]

Hi

There is no need to feed the 58516 or the antenna with any sort of super power 
supply.
It’s just a simple RF amplifier in there. It’s designed to be feed off of the 
bias supply coming out of a GPS module. If a module has a dedicated
78L05 style regulator on it, it’s one of the better ones ….

Bob

> On Sep 3, 2017, at 2:55 AM, Clemgill  wrote:
> 
> Hi Clay,
> Intersting subject.
> What design for ultra stable/clean power supply are you using please ?
> Thx,
> Gilles.
> 
>> On Sep 2, 2017, at 22:47, Clay Autery  wrote:
>> 
>> PCTEL GPS-TMG-HR-26NCM Antenna. 
>> http://www.neobits.com/pctel_maxrad_gps_tmg_hr_26ncm_high_rejection_gps_p2769137.htm
>> 
>> Can't say what the gain tolerances are, but it appears to be a pretty
>> decent quality part.
>> 
>> The distribution amp is an HP 58516A GPS L1 Distribution Amp with the
>> external power supply tap which will be fed with an ultras stable/clean
>> adjustable linear power supply.  As I understand it, this is a unity
>> gain amp, so there should be little to no insertion loss or distro losses.
>> 
>> The distribution amp will be mounted near the devices such that amp to
>> device jumpers will all be < 1 meter/3.28 feet.  Likely a lot less.  ALL
>> Times N-connectors until reaching a connector TM doesn't make.
>> 
>> __
>> Clay Autery, KY5G
>> 
>>> On 9/2/2017 3:26 PM, Bob kb8tq wrote:
>>> Hi
>>> 
>>> A lot depends on what comes after the feed cable. The “disto amp” will 
>>> determine 
>>> a lot. You likely need 10 db of net gain in front of it to keep things 
>>> running ok. For an
>>> antenna that is *really* 26 db (as opposed to 26 db +/- 6 db), that would 
>>> come out to
>>> 16 db of feed line loss. This isn’t a terribly surprising outcome. The 
>>> antennas are designed
>>> for installations that run 150’ or more of coax ….
>>> 
>>> Bob
>>> 
 On Sep 2, 2017, at 2:57 PM, Clay Autery  wrote:
 
 Having decision-making problems for the materials for my GPS main
 feedline.  Going to use a TM LMR stock, just can't decide how big to go
 with it...
 
 26 dB 5vdc antenna on top of a 38 foot mast.  Feed will come down the
 inside/center of mast and exit near the bottom, thence routed through a
 window and to the GPS distro amp. Antenna will feed GPSDO, NTP Server,
 Blitzortung System Blue station, and one other device TBD.
 
 Just cannot decide how big to go with the antenna to distro amp feed... 
 Assuming 50 feet total (38' mast + 12 feet to amp in shack) @ 1800 MHz
 (closest to 1725 MHz), here are the losses from just this piece
 (ignoring the amp to device jumpers):
 
 -240 = 5.45 dB XXX - too much loss?
 -400 = 2.85 dB
 -500 = 2.30 dB  XXX - too hard to find
 -600 = 1.85 dB
 -900 = 1.25 dB
 
 Money not necessarily a consideration as this is a short run for a
 permanent installation.  Don't anticipate ever moving the GPS antenna to
 the tower.
 For 900 and likely 600, likely would not be able to do it in one piece
 as routing it out of the mast and into the shack would get complicated. 
 Would likely bring it out of the mast at the bottom with a right angle
 connector, and then use a smaller diameter jumper for the last 12 feet.
 500 is pretty uncommon stock wise and it and connectors are harder to find.
 
 I already have the tooling for both 240 and 400... but I definitely
 don't want to challenge ANY of the devices for signal gain.
 
 So it mostly boils down to easy vs. more effort ($$ aside)  Is it
 worth the additional trouble to move from -400 to -600 or -900?  To NOT
 lose the 1-1.6 dB additional?
 
 I'd appreciate your recommendation and reasoning. Thanks in advance!
 
 73,
 
 -- 
 __
 Clay Autery, KY5G
 MONTAC Enterprises
 (318) 518-1389
>> 
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Re: [time-nuts] GPS Antenna Feed Line Decision

[Wes]

On 9/2/2017 4:48 PM, Clay Autery wrote:

Thanks for the response...

Not sure why you and the other guy both recommended RG-6 75-Ohm cable
and F-connectors, when the nominal impedance of literally everything
else in the system is 50 Ohm, including the antenna and the HP GPS
Distribution Amp  And then adding N to F adapters?
As "the other guy" (I think) let me say that the impedance mismatch is 
immaterial and in my case I have one GPSDO with an SMA connector and another 
with a BNC and an antenna with an SMA.  So I "adapt" no matter what I do.  
Because I understand the cascaded noise figure equations, I know that I don't 
need an active distribution amplifier to feed just these two devices, so a $5.00 
"F" connector splitter is adequate. 
(https://www.markertek.com/product/201-232/2-way-2-4ghz-90db-satellite-splitter-dc-power-passing-to-one-port)

Doesn't make any sense unless one has $$ as a top priority, already has
a spool of RG-6 quad shield, etc...  but I specifically stated that $$
is not a top priority  Not really even in the top 5 or 10...

Then by all means you should use L-band waveguide. :-)

Wes

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Re: [time-nuts] GPS Antenna Feed Line Decision

[Attila Kinali]

On Sat, 2 Sep 2017 18:48:52 -0500
Clay Autery  wrote:


> Not sure why you and the other guy both recommended RG-6 75-Ohm cable
> and F-connectors, when the nominal impedance of literally everything
> else in the system is 50 Ohm, including the antenna and the HP GPS
> Distribution Amp  And then adding N to F adapters?

Because it doesn't matter in a receive only application.
The transmission coefficient for a 75R<->50R step is 0.8, or -1.9dB.
In return, you can get a much better cable for half the price with
less damping. Not to talk about all the other bits and pieces that
are readily available for 75R F connectors. Like lightning arrestors
and grounding blocks. And please, include at least a lightning arrestor
at the point where the cable enters the building!


> Doesn't make any sense unless one has $$ as a top priority, already has
> a spool of RG-6 quad shield, etc...  but I specifically stated that $$
> is not a top priority  Not really even in the top 5 or 10...


If you have more than enough money, then by all means go for the 50R
solution :-)
 
> Strain relief solution:  Really depends upon which cable stock I end up
> using  Obviously, the larger the cable, the more weight will be
> suspended under the antenna (approx. 38 feet, depending on where I pull
> the cable out of the mast at the bottom.  (The mast is on a tilt-base of
> my own construction  which brings up a valid consideration.  it is
> already a chore to walk the mast up manually.  The more weight added at
> the top and inside the mast, the more difficult a manual walk-up will
> be.  I'd prefer to keep this a manual tilt for now...  at least until I
> add the tri-band vertical dipole)
> 
> LMR-400 would be less than 4 lbs total weight...  I'd likely suspend the
> cable by the connector alone. (although, it wouldn't be JUST the
> crimp...  The connector would have at a minimum, 1 layer of
> adhesive-lined shrink tube... probably 2, with the second, overlapping. 
> Then a nice wrap of self-fusing tape and then electrical tape over that.
> Even LMR-600 could be suspended by the connector alone, at 5 lbs max in
> the 38 foot max vertical section.
> I do have several methods of secondary suspension within the top (and/or
> second) mast section though if I decide I need it.

You do not want to have 2kg of weight on a RF connector.
Even if it will hold now, over time material creep will lead to
intermediate faults. Better use a dedicated strain relieve. This
can be something as simple as a wire wound around the cable that
holds the weight.

 
Attila Kinali

-- 
You know, the very powerful and the very stupid have one thing in common.
They don't alters their views to fit the facts, they alter the facts to
fit the views, which can be uncomfortable if you happen to be one of the
facts that needs altering.  -- The Doctor
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Re: [time-nuts] GPS Antenna Feed Line Decision

[Clemgill]

Hi Clay,
Intersting subject.
What design for ultra stable/clean power supply are you using please ?
Thx,
Gilles.

> On Sep 2, 2017, at 22:47, Clay Autery  wrote:
> 
> PCTEL GPS-TMG-HR-26NCM Antenna. 
> http://www.neobits.com/pctel_maxrad_gps_tmg_hr_26ncm_high_rejection_gps_p2769137.htm
> 
> Can't say what the gain tolerances are, but it appears to be a pretty
> decent quality part.
> 
> The distribution amp is an HP 58516A GPS L1 Distribution Amp with the
> external power supply tap which will be fed with an ultras stable/clean
> adjustable linear power supply.  As I understand it, this is a unity
> gain amp, so there should be little to no insertion loss or distro losses.
> 
> The distribution amp will be mounted near the devices such that amp to
> device jumpers will all be < 1 meter/3.28 feet.  Likely a lot less.  ALL
> Times N-connectors until reaching a connector TM doesn't make.
> 
> __
> Clay Autery, KY5G
> 
>> On 9/2/2017 3:26 PM, Bob kb8tq wrote:
>> Hi
>> 
>> A lot depends on what comes after the feed cable. The “disto amp” will 
>> determine 
>> a lot. You likely need 10 db of net gain in front of it to keep things 
>> running ok. For an
>> antenna that is *really* 26 db (as opposed to 26 db +/- 6 db), that would 
>> come out to
>> 16 db of feed line loss. This isn’t a terribly surprising outcome. The 
>> antennas are designed
>> for installations that run 150’ or more of coax ….
>> 
>> Bob
>> 
>>> On Sep 2, 2017, at 2:57 PM, Clay Autery  wrote:
>>> 
>>> Having decision-making problems for the materials for my GPS main
>>> feedline.  Going to use a TM LMR stock, just can't decide how big to go
>>> with it...
>>> 
>>> 26 dB 5vdc antenna on top of a 38 foot mast.  Feed will come down the
>>> inside/center of mast and exit near the bottom, thence routed through a
>>> window and to the GPS distro amp. Antenna will feed GPSDO, NTP Server,
>>> Blitzortung System Blue station, and one other device TBD.
>>> 
>>> Just cannot decide how big to go with the antenna to distro amp feed... 
>>> Assuming 50 feet total (38' mast + 12 feet to amp in shack) @ 1800 MHz
>>> (closest to 1725 MHz), here are the losses from just this piece
>>> (ignoring the amp to device jumpers):
>>> 
>>> -240 = 5.45 dB XXX - too much loss?
>>> -400 = 2.85 dB
>>> -500 = 2.30 dB  XXX - too hard to find
>>> -600 = 1.85 dB
>>> -900 = 1.25 dB
>>> 
>>> Money not necessarily a consideration as this is a short run for a
>>> permanent installation.  Don't anticipate ever moving the GPS antenna to
>>> the tower.
>>> For 900 and likely 600, likely would not be able to do it in one piece
>>> as routing it out of the mast and into the shack would get complicated. 
>>> Would likely bring it out of the mast at the bottom with a right angle
>>> connector, and then use a smaller diameter jumper for the last 12 feet.
>>> 500 is pretty uncommon stock wise and it and connectors are harder to find.
>>> 
>>> I already have the tooling for both 240 and 400... but I definitely
>>> don't want to challenge ANY of the devices for signal gain.
>>> 
>>> So it mostly boils down to easy vs. more effort ($$ aside)  Is it
>>> worth the additional trouble to move from -400 to -600 or -900?  To NOT
>>> lose the 1-1.6 dB additional?
>>> 
>>> I'd appreciate your recommendation and reasoning. Thanks in advance!
>>> 
>>> 73,
>>> 
>>> -- 
>>> __
>>> Clay Autery, KY5G
>>> MONTAC Enterprises
>>> (318) 518-1389
> 
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Re: [time-nuts] GPS Antenna Feed Line Decision

[Clay Autery]

Thanks for the response...

Not sure why you and the other guy both recommended RG-6 75-Ohm cable
and F-connectors, when the nominal impedance of literally everything
else in the system is 50 Ohm, including the antenna and the HP GPS
Distribution Amp  And then adding N to F adapters?

Doesn't make any sense unless one has $$ as a top priority, already has
a spool of RG-6 quad shield, etc...  but I specifically stated that $$
is not a top priority  Not really even in the top 5 or 10...

The whole point of this exercise is to put up a semi-permanent SINGLE
antenna/feed-line install that will supply all 4 ports of the HP amp
with the least compromised signal within reason 4 now, and 8
whenever I can find the HP 8-way distro amp with external power input.

Strain relief solution:  Really depends upon which cable stock I end up
using  Obviously, the larger the cable, the more weight will be
suspended under the antenna (approx. 38 feet, depending on where I pull
the cable out of the mast at the bottom.  (The mast is on a tilt-base of
my own construction  which brings up a valid consideration.  it is
already a chore to walk the mast up manually.  The more weight added at
the top and inside the mast, the more difficult a manual walk-up will
be.  I'd prefer to keep this a manual tilt for now...  at least until I
add the tri-band vertical dipole)

LMR-400 would be less than 4 lbs total weight...  I'd likely suspend the
cable by the connector alone. (although, it wouldn't be JUST the
crimp...  The connector would have at a minimum, 1 layer of
adhesive-lined shrink tube... probably 2, with the second, overlapping. 
Then a nice wrap of self-fusing tape and then electrical tape over that.
Even LMR-600 could be suspended by the connector alone, at 5 lbs max in
the 38 foot max vertical section.
I do have several methods of secondary suspension within the top (and/or
second) mast section though if I decide I need it.

Also prefer to keep all the connectors N-type as much as possible since
that is the station standard.

73,

__
Clay Autery, KY5G

On 9/2/2017 6:07 PM, Mike Naruta AA8K wrote:
>
> Clay, you may wish to consider using a quality RG-6 with F
> connectors.  Grounding blocks are readily available for the base of
> your mast and the entrance to your house.  Also, off-the-shelf
> over-voltage protectors (Zap-Tech) are available. I even found an
> F-to-N adapter for the antenna on Amazon.  Watch out for the ones with
> metric N threads though.
>
> For my 25 meter run I was going to use an existing one inch Heliax,
> but pulled a run of Belden RG-6 instead after learning that Trimble
> used RG-6.
>
> It worked well directly connected to a Trimble Thunderbolt; now it is
> connected to a Symmetricon 58535A GPS L1 distribution amplifier.
>
>
> My Blitzortung System Red station has been running fine in my attic
> (Michigan) on a Motorola 97 Oncore patch antenna fastened against the
> roof underside.  It is looking through wood, shingles, and nails (and
> a tree and antennas and utility lines).
>
>
> How are you planning to do strain-relief on the vertical run of coax
> inside of your mast?
>
>
> Mike - AA8K
>
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Re: [time-nuts] GPS Antenna Feed Line Decision

[Clay Autery]

HP 58516A GPS L1 Disribution Amplifier ( 4-way with external power
supply input)

__
Clay Autery, KY5G

On 9/2/2017 3:38 PM, Pete Lancashire wrote:
> What are you using for a distribution amplifier ?
>
> On Sat, Sep 2, 2017 at 11:57 AM, Clay Autery  wrote:
>
>> Having decision-making problems for the materials for my GPS main
>> feedline.  Going to use a TM LMR stock, just can't decide how big to go
>> with it...
>>
>> 26 dB 5vdc antenna on top of a 38 foot mast.  Feed will come down the
>> inside/center of mast and exit near the bottom, thence routed through a
>> window and to the GPS distro amp. Antenna will feed GPSDO, NTP Server,
>> Blitzortung System Blue station, and one other device TBD.
>>
>> Just cannot decide how big to go with the antenna to distro amp feed...
>> Assuming 50 feet total (38' mast + 12 feet to amp in shack) @ 1800 MHz
>> (closest to 1725 MHz), here are the losses from just this piece
>> (ignoring the amp to device jumpers):
>>
>> -240 = 5.45 dB XXX - too much loss?
>> -400 = 2.85 dB
>> -500 = 2.30 dB  XXX - too hard to find
>> -600 = 1.85 dB
>> -900 = 1.25 dB
>>
>> Money not necessarily a consideration as this is a short run for a
>> permanent installation.  Don't anticipate ever moving the GPS antenna to
>> the tower.
>> For 900 and likely 600, likely would not be able to do it in one piece
>> as routing it out of the mast and into the shack would get complicated.
>> Would likely bring it out of the mast at the bottom with a right angle
>> connector, and then use a smaller diameter jumper for the last 12 feet.
>> 500 is pretty uncommon stock wise and it and connectors are harder to find.
>>
>> I already have the tooling for both 240 and 400... but I definitely
>> don't want to challenge ANY of the devices for signal gain.
>>
>> So it mostly boils down to easy vs. more effort ($$ aside)  Is it
>> worth the additional trouble to move from -400 to -600 or -900?  To NOT
>> lose the 1-1.6 dB additional?
>>
>> I'd appreciate your recommendation and reasoning. Thanks in advance!
>>
>> 73,
>>
>> --
>> __
>> Clay Autery, KY5G
>> MONTAC Enterprises
>> (318) 518-1389
>>
>> ___
>> time-nuts mailing list -- time-nuts@febo.com
>> To unsubscribe, go to https://www.febo.com/cgi-bin/
>> mailman/listinfo/time-nuts
>> and follow the instructions there.
>>
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Re: [time-nuts] GPS Antenna Feed Line Decision

[Clay Autery]

PCTEL GPS-TMG-HR-26NCM Antenna. 
http://www.neobits.com/pctel_maxrad_gps_tmg_hr_26ncm_high_rejection_gps_p2769137.htm

Can't say what the gain tolerances are, but it appears to be a pretty
decent quality part.

The distribution amp is an HP 58516A GPS L1 Distribution Amp with the
external power supply tap which will be fed with an ultras stable/clean
adjustable linear power supply.  As I understand it, this is a unity
gain amp, so there should be little to no insertion loss or distro losses.

The distribution amp will be mounted near the devices such that amp to
device jumpers will all be < 1 meter/3.28 feet.  Likely a lot less.  ALL
Times N-connectors until reaching a connector TM doesn't make.

__
Clay Autery, KY5G

On 9/2/2017 3:26 PM, Bob kb8tq wrote:
> Hi
>
> A lot depends on what comes after the feed cable. The “disto amp” will 
> determine 
> a lot. You likely need 10 db of net gain in front of it to keep things 
> running ok. For an
> antenna that is *really* 26 db (as opposed to 26 db +/- 6 db), that would 
> come out to
> 16 db of feed line loss. This isn’t a terribly surprising outcome. The 
> antennas are designed
> for installations that run 150’ or more of coax ….
>
> Bob
>
>> On Sep 2, 2017, at 2:57 PM, Clay Autery  wrote:
>>
>> Having decision-making problems for the materials for my GPS main
>> feedline.  Going to use a TM LMR stock, just can't decide how big to go
>> with it...
>>
>> 26 dB 5vdc antenna on top of a 38 foot mast.  Feed will come down the
>> inside/center of mast and exit near the bottom, thence routed through a
>> window and to the GPS distro amp. Antenna will feed GPSDO, NTP Server,
>> Blitzortung System Blue station, and one other device TBD.
>>
>> Just cannot decide how big to go with the antenna to distro amp feed... 
>> Assuming 50 feet total (38' mast + 12 feet to amp in shack) @ 1800 MHz
>> (closest to 1725 MHz), here are the losses from just this piece
>> (ignoring the amp to device jumpers):
>>
>> -240 = 5.45 dB XXX - too much loss?
>> -400 = 2.85 dB
>> -500 = 2.30 dB  XXX - too hard to find
>> -600 = 1.85 dB
>> -900 = 1.25 dB
>>
>> Money not necessarily a consideration as this is a short run for a
>> permanent installation.  Don't anticipate ever moving the GPS antenna to
>> the tower.
>> For 900 and likely 600, likely would not be able to do it in one piece
>> as routing it out of the mast and into the shack would get complicated. 
>> Would likely bring it out of the mast at the bottom with a right angle
>> connector, and then use a smaller diameter jumper for the last 12 feet.
>> 500 is pretty uncommon stock wise and it and connectors are harder to find.
>>
>> I already have the tooling for both 240 and 400... but I definitely
>> don't want to challenge ANY of the devices for signal gain.
>>
>> So it mostly boils down to easy vs. more effort ($$ aside)  Is it
>> worth the additional trouble to move from -400 to -600 or -900?  To NOT
>> lose the 1-1.6 dB additional?
>>
>> I'd appreciate your recommendation and reasoning. Thanks in advance!
>>
>> 73,
>>
>> -- 
>> __
>> Clay Autery, KY5G
>> MONTAC Enterprises
>> (318) 518-1389

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Re: [time-nuts] GPS Antenna Feed Line Decision

[Bill Hawkins]

My HP conical antennas had N connectors, so I used 50 feet of RG-8.
Z3801 receivers never had a problem.

RG-8 is a sturdy cable, which may be the primary consideration for a 38
foot drop unsupported through the mast.

Don't have any comparison to lighter cable, though.

Bill Hawkins
 

-Original Message-
From: time-nuts [mailto:time-nuts-boun...@febo.com] On Behalf Of Clay
Autery
Sent: Saturday, September 02, 2017 1:57 PM
To: Time Nuts
Subject: [time-nuts] GPS Antenna Feed Line Decision

Having decision-making problems for the materials for my GPS main
feedline.  Going to use a TM LMR stock, just can't decide how big to go
with it...

26 dB 5vdc antenna on top of a 38 foot mast.  Feed will come down the
inside/center of mast and exit near the bottom, thence routed through a
window and to the GPS distro amp. Antenna will feed GPSDO, NTP Server,
Blitzortung System Blue station, and one other device TBD.

Just cannot decide how big to go with the antenna to distro amp feed...
Assuming 50 feet total (38' mast + 12 feet to amp in shack) @ 1800 MHz
(closest to 1725 MHz), here are the losses from just this piece
(ignoring the amp to device jumpers):

-240 = 5.45 dB XXX - too much loss?
-400 = 2.85 dB
-500 = 2.30 dB  XXX - too hard to find
-600 = 1.85 dB
-900 = 1.25 dB

Money not necessarily a consideration as this is a short run for a
permanent installation.  Don't anticipate ever moving the GPS antenna to
the tower.
For 900 and likely 600, likely would not be able to do it in one piece
as routing it out of the mast and into the shack would get complicated.
Would likely bring it out of the mast at the bottom with a right angle
connector, and then use a smaller diameter jumper for the last 12 feet.
500 is pretty uncommon stock wise and it and connectors are harder to
find.

I already have the tooling for both 240 and 400... but I definitely
don't want to challenge ANY of the devices for signal gain.

So it mostly boils down to easy vs. more effort ($$ aside)  Is it
worth the additional trouble to move from -400 to -600 or -900?  To NOT
lose the 1-1.6 dB additional?

I'd appreciate your recommendation and reasoning. Thanks in advance!

73,

--
__
Clay Autery, KY5G
MONTAC Enterprises
(318) 518-1389

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Re: [time-nuts] GPS Antenna Feed Line Decision

[William H. Fite]

True, though a friend of mine used LMR-400.


On Saturday, September 2, 2017, Mark Sims  wrote:

> Cheap RG-59 cable coax is more than sufficient for 50 .. 150+ feet (unless
> you are doing geodetic level GPS work).  It is recommended by several GPSDO
> makers.  The 50/75 ohm mismatch is not an issue.  No need to waste money on
> fancy pants artisanal luxury coax.
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-- 
I wanted to be a rocket scientist but my advisor said I'd be wasting my
talent.
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[time-nuts] GPS Antenna Feed Line Decision

[Mark Sims]

Cheap RG-59 cable coax is more than sufficient for 50 .. 150+ feet (unless you 
are doing geodetic level GPS work).  It is recommended by several GPSDO makers. 
 The 50/75 ohm mismatch is not an issue.  No need to waste money on fancy pants 
artisanal luxury coax.
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Re: [time-nuts] GPS Antenna Feed Line Decision

[Bob kb8tq]

Hi

Modern distribution amp chips are likely to be sub 2 db NF. Gain is generally 
just a bit more than
the loss through any post filtering and the passive power splitter after it. 

Bob

> On Sep 2, 2017, at 7:02 PM, Wes  wrote:
> 
> This is just a cascaded noise figure situation.
> 
> The first stage is the antenna (preamp) which has 26 dB gain (assumed) and an 
> unknown noise figure. Assume it's a dB or so. Let the second stage gain be a 
> negative value equal to the cable loss and the second stage noise figure be 
> equal to the cable loss in dB.  Assume a lousy 10 dB NF and 10 dB gain for 
> the distribution amp.
> 
> If the cable loss is 5 dB then the cascaded noise figure and gain are: 1.26 
> dB, 31 dB gain.
> 
> If the cable loss is 2 dB then the cascaded noise figure and gain are: 1.13 
> dB, 33 dB gain.
> 
> I would use RG-6.
> 
> See: https://www.pasternack.com/t-calculator-noise-figure.aspx
> 
> The secret here is the 26 dB gain.
> 
> 
> Wes  N7WS
> 
> On 9/2/2017 11:57 AM, Clay Autery wrote:
>> Having decision-making problems for the materials for my GPS main
>> feedline.  Going to use a TM LMR stock, just can't decide how big to go
>> with it...
>> 
>> 26 dB 5vdc antenna on top of a 38 foot mast.  Feed will come down the
>> inside/center of mast and exit near the bottom, thence routed through a
>> window and to the GPS distro amp. Antenna will feed GPSDO, NTP Server,
>> Blitzortung System Blue station, and one other device TBD.
>> 
>> Just cannot decide how big to go with the antenna to distro amp feed...
>> Assuming 50 feet total (38' mast + 12 feet to amp in shack) @ 1800 MHz
>> (closest to 1725 MHz), here are the losses from just this piece
>> (ignoring the amp to device jumpers):
>> 
>> -240 = 5.45 dB XXX - too much loss?
>> -400 = 2.85 dB
>> -500 = 2.30 dB  XXX - too hard to find
>> -600 = 1.85 dB
>> -900 = 1.25 dB
>> 
>> Money not necessarily a consideration as this is a short run for a
>> permanent installation.  Don't anticipate ever moving the GPS antenna to
>> the tower.
>> For 900 and likely 600, likely would not be able to do it in one piece
>> as routing it out of the mast and into the shack would get complicated.
>> Would likely bring it out of the mast at the bottom with a right angle
>> connector, and then use a smaller diameter jumper for the last 12 feet.
>> 500 is pretty uncommon stock wise and it and connectors are harder to find.
>> 
>> I already have the tooling for both 240 and 400... but I definitely
>> don't want to challenge ANY of the devices for signal gain.
>> 
>> So it mostly boils down to easy vs. more effort ($$ aside)  Is it
>> worth the additional trouble to move from -400 to -600 or -900?  To NOT
>> lose the 1-1.6 dB additional?
>> 
>> I'd appreciate your recommendation and reasoning. Thanks in advance!
>> 
>> 73,
>> 
> 
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Re: [time-nuts] GPS Antenna Feed Line Decision

[Mike Naruta AA8K]

On 09/02/2017 02:57 PM, Clay Autery wrote:

Having decision-making problems for the materials for my GPS main
feedline.  Going to use a TM LMR stock, just can't decide how big to go
with it...

26 dB 5vdc antenna on top of a 38 foot mast.  Feed will come down the
inside/center of mast and exit near the bottom, thence routed through a
window and to the GPS distro amp. Antenna will feed GPSDO, NTP Server,
Blitzortung System Blue station, and one other device TBD.


...


I'd appreciate your recommendation and reasoning. Thanks in advance!

73,



Clay, you may wish to consider using a quality RG-6 with F 
connectors.  Grounding blocks are readily available for the base 
of your mast and the entrance to your house.  Also, 
off-the-shelf over-voltage protectors (Zap-Tech) are available. 
I even found an F-to-N adapter for the antenna on Amazon.  Watch 
out for the ones with metric N threads though.


For my 25 meter run I was going to use an existing one inch 
Heliax, but pulled a run of Belden RG-6 instead after learning 
that Trimble used RG-6.


It worked well directly connected to a Trimble Thunderbolt; now 
it is connected to a Symmetricon 58535A GPS L1 distribution 
amplifier.



My Blitzortung System Red station has been running fine in my 
attic (Michigan) on a Motorola 97 Oncore patch antenna fastened 
against the roof underside.  It is looking through wood, 
shingles, and nails (and a tree and antennas and utility lines).



How are you planning to do strain-relief on the vertical run of 
coax inside of your mast?



Mike - AA8K

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Re: [time-nuts] GPS Antenna Feed Line Decision

[Wes]

This is just a cascaded noise figure situation.

The first stage is the antenna (preamp) which has 26 dB gain (assumed) and an 
unknown noise figure. Assume it's a dB or so. Let the second stage gain be a 
negative value equal to the cable loss and the second stage noise figure be 
equal to the cable loss in dB.  Assume a lousy 10 dB NF and 10 dB gain for the 
distribution amp.


If the cable loss is 5 dB then the cascaded noise figure and gain are: 1.26 dB, 
31 dB gain.


If the cable loss is 2 dB then the cascaded noise figure and gain are: 1.13 dB, 
33 dB gain.


I would use RG-6.

See: https://www.pasternack.com/t-calculator-noise-figure.aspx

The secret here is the 26 dB gain.


Wes  N7WS

On 9/2/2017 11:57 AM, Clay Autery wrote:

Having decision-making problems for the materials for my GPS main
feedline.  Going to use a TM LMR stock, just can't decide how big to go
with it...

26 dB 5vdc antenna on top of a 38 foot mast.  Feed will come down the
inside/center of mast and exit near the bottom, thence routed through a
window and to the GPS distro amp. Antenna will feed GPSDO, NTP Server,
Blitzortung System Blue station, and one other device TBD.

Just cannot decide how big to go with the antenna to distro amp feed...
Assuming 50 feet total (38' mast + 12 feet to amp in shack) @ 1800 MHz
(closest to 1725 MHz), here are the losses from just this piece
(ignoring the amp to device jumpers):

-240 = 5.45 dB XXX - too much loss?
-400 = 2.85 dB
-500 = 2.30 dB  XXX - too hard to find
-600 = 1.85 dB
-900 = 1.25 dB

Money not necessarily a consideration as this is a short run for a
permanent installation.  Don't anticipate ever moving the GPS antenna to
the tower.
For 900 and likely 600, likely would not be able to do it in one piece
as routing it out of the mast and into the shack would get complicated.
Would likely bring it out of the mast at the bottom with a right angle
connector, and then use a smaller diameter jumper for the last 12 feet.
500 is pretty uncommon stock wise and it and connectors are harder to find.

I already have the tooling for both 240 and 400... but I definitely
don't want to challenge ANY of the devices for signal gain.

So it mostly boils down to easy vs. more effort ($$ aside)  Is it
worth the additional trouble to move from -400 to -600 or -900?  To NOT
lose the 1-1.6 dB additional?

I'd appreciate your recommendation and reasoning. Thanks in advance!

73,



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Re: [time-nuts] GPS Antenna Feed Line Decision

[Pete Lancashire]

What are you using for a distribution amplifier ?

On Sat, Sep 2, 2017 at 11:57 AM, Clay Autery  wrote:

> Having decision-making problems for the materials for my GPS main
> feedline.  Going to use a TM LMR stock, just can't decide how big to go
> with it...
>
> 26 dB 5vdc antenna on top of a 38 foot mast.  Feed will come down the
> inside/center of mast and exit near the bottom, thence routed through a
> window and to the GPS distro amp. Antenna will feed GPSDO, NTP Server,
> Blitzortung System Blue station, and one other device TBD.
>
> Just cannot decide how big to go with the antenna to distro amp feed...
> Assuming 50 feet total (38' mast + 12 feet to amp in shack) @ 1800 MHz
> (closest to 1725 MHz), here are the losses from just this piece
> (ignoring the amp to device jumpers):
>
> -240 = 5.45 dB XXX - too much loss?
> -400 = 2.85 dB
> -500 = 2.30 dB  XXX - too hard to find
> -600 = 1.85 dB
> -900 = 1.25 dB
>
> Money not necessarily a consideration as this is a short run for a
> permanent installation.  Don't anticipate ever moving the GPS antenna to
> the tower.
> For 900 and likely 600, likely would not be able to do it in one piece
> as routing it out of the mast and into the shack would get complicated.
> Would likely bring it out of the mast at the bottom with a right angle
> connector, and then use a smaller diameter jumper for the last 12 feet.
> 500 is pretty uncommon stock wise and it and connectors are harder to find.
>
> I already have the tooling for both 240 and 400... but I definitely
> don't want to challenge ANY of the devices for signal gain.
>
> So it mostly boils down to easy vs. more effort ($$ aside)  Is it
> worth the additional trouble to move from -400 to -600 or -900?  To NOT
> lose the 1-1.6 dB additional?
>
> I'd appreciate your recommendation and reasoning. Thanks in advance!
>
> 73,
>
> --
> __
> Clay Autery, KY5G
> MONTAC Enterprises
> (318) 518-1389
>
> ___
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Re: [time-nuts] GPS Antenna Feed Line Decision

[Bob kb8tq]

Hi

A lot depends on what comes after the feed cable. The “disto amp” will 
determine 
a lot. You likely need 10 db of net gain in front of it to keep things running 
ok. For an
antenna that is *really* 26 db (as opposed to 26 db +/- 6 db), that would come 
out to
16 db of feed line loss. This isn’t a terribly surprising outcome. The antennas 
are designed
for installations that run 150’ or more of coax ….

Bob

> On Sep 2, 2017, at 2:57 PM, Clay Autery  wrote:
> 
> Having decision-making problems for the materials for my GPS main
> feedline.  Going to use a TM LMR stock, just can't decide how big to go
> with it...
> 
> 26 dB 5vdc antenna on top of a 38 foot mast.  Feed will come down the
> inside/center of mast and exit near the bottom, thence routed through a
> window and to the GPS distro amp. Antenna will feed GPSDO, NTP Server,
> Blitzortung System Blue station, and one other device TBD.
> 
> Just cannot decide how big to go with the antenna to distro amp feed... 
> Assuming 50 feet total (38' mast + 12 feet to amp in shack) @ 1800 MHz
> (closest to 1725 MHz), here are the losses from just this piece
> (ignoring the amp to device jumpers):
> 
> -240 = 5.45 dB XXX - too much loss?
> -400 = 2.85 dB
> -500 = 2.30 dB  XXX - too hard to find
> -600 = 1.85 dB
> -900 = 1.25 dB
> 
> Money not necessarily a consideration as this is a short run for a
> permanent installation.  Don't anticipate ever moving the GPS antenna to
> the tower.
> For 900 and likely 600, likely would not be able to do it in one piece
> as routing it out of the mast and into the shack would get complicated. 
> Would likely bring it out of the mast at the bottom with a right angle
> connector, and then use a smaller diameter jumper for the last 12 feet.
> 500 is pretty uncommon stock wise and it and connectors are harder to find.
> 
> I already have the tooling for both 240 and 400... but I definitely
> don't want to challenge ANY of the devices for signal gain.
> 
> So it mostly boils down to easy vs. more effort ($$ aside)  Is it
> worth the additional trouble to move from -400 to -600 or -900?  To NOT
> lose the 1-1.6 dB additional?
> 
> I'd appreciate your recommendation and reasoning. Thanks in advance!
> 
> 73,
> 
> -- 
> __
> Clay Autery, KY5G
> MONTAC Enterprises
> (318) 518-1389
> 
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[time-nuts] GPS Antenna Feed Line Decision

[Clay Autery]

Having decision-making problems for the materials for my GPS main
feedline.  Going to use a TM LMR stock, just can't decide how big to go
with it...

26 dB 5vdc antenna on top of a 38 foot mast.  Feed will come down the
inside/center of mast and exit near the bottom, thence routed through a
window and to the GPS distro amp. Antenna will feed GPSDO, NTP Server,
Blitzortung System Blue station, and one other device TBD.

Just cannot decide how big to go with the antenna to distro amp feed... 
Assuming 50 feet total (38' mast + 12 feet to amp in shack) @ 1800 MHz
(closest to 1725 MHz), here are the losses from just this piece
(ignoring the amp to device jumpers):

-240 = 5.45 dB XXX - too much loss?
-400 = 2.85 dB
-500 = 2.30 dB  XXX - too hard to find
-600 = 1.85 dB
-900 = 1.25 dB

Money not necessarily a consideration as this is a short run for a
permanent installation.  Don't anticipate ever moving the GPS antenna to
the tower.
For 900 and likely 600, likely would not be able to do it in one piece
as routing it out of the mast and into the shack would get complicated. 
Would likely bring it out of the mast at the bottom with a right angle
connector, and then use a smaller diameter jumper for the last 12 feet.
500 is pretty uncommon stock wise and it and connectors are harder to find.

I already have the tooling for both 240 and 400... but I definitely
don't want to challenge ANY of the devices for signal gain.

So it mostly boils down to easy vs. more effort ($$ aside)  Is it
worth the additional trouble to move from -400 to -600 or -900?  To NOT
lose the 1-1.6 dB additional?

I'd appreciate your recommendation and reasoning. Thanks in advance!

73,

-- 
__
Clay Autery, KY5G
MONTAC Enterprises
(318) 518-1389

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Re: [time-nuts] GPS Antenna on Tower.

[Wes]

Mark,

Excuse my ignorance but where do I find this version?

Wes

On 6/20/2017 9:34 AM, Mark Sims wrote:

I just added the ability to calculate solid earth tides and the vertical 
gravity offset due to the sun and moon to Lady Heather.   The lat/lon offset is 
typically around +/- 60 cm per day.Vertical offset is around  +/- 180mm.  
Depending upon the day and where you are, the swings are not symmetrical around 
0.0



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Re: [time-nuts] GPS Antenna on Tower.

[Attila Kinali]

On Tue, 20 Jun 2017 16:34:14 +
Mark Sims  wrote:

> I just added the ability to calculate solid earth tides and the vertical 
> gravity offset due to the sun and moon to Lady Heather.   

Cool! How do you calculate the displacement on a fixed position receiver?

> The lat/lon offset 
> is typically around +/- 60 cm per day.Vertical offset is around  +/- 
> 180mm.  Depending upon the day and where you are, the swings are not 
> symmetrical around 0.0   

This might be of interest:
http://www.unoosa.org/documents/pdf/psa/activities/2012/un-latvia/ppt/2-11.pdf
(more papers available upon request)

> Solid earth tides are a BIG factor in precision geodesy.   Gravity offset is 
> a big issue for precision pendulum nuts.  If your pendulum clock cannot
> detect gravity offsets (very few can) it's not nutty enough.

:-D

Attila Kinali

-- 
It is upon moral qualities that a society is ultimately founded. All 
the prosperity and technological sophistication in the world is of no 
use without that foundation.
 -- Miss Matheson, The Diamond Age, Neil Stephenson
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Re: [time-nuts] GPS Antenna on Tower.

[Hal Murray]

How do the GPS control/monitoring stations handle Earth tides?

My guess is they have another nearby antenna that they can link up to VLBI 
data.

-- 
These are my opinions.  I hate spam.



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Re: [time-nuts] GPS Antenna on Tower.

[Bob kb8tq]

Hi

Earth tides are at least as crazy a topic as time. There are formulas that will 
let you incorporate
the effect of Pluto on solid Earth tides.

Bob

> On Jun 20, 2017, at 7:21 PM, Peter Vince  wrote:
> 
> Hi Mark,
> 
> This is all new information to me - and fascinating!  Have you just
> "calculated" the offsets (using known values from somewhere), or "measured"
> it by very long term averaging of the GPS position information?
> 
> Peter Vince
> 
> 
> On 20 June 2017 at 17:34, Mark Sims  wrote:
> 
>> I just added the ability to calculate solid earth tides and the vertical
>> gravity offset due to the sun and moon to Lady Heather.   The lat/lon
>> offset is typically around +/- 60 cm per day.Vertical offset is around
>> +/- 180mm.  Depending upon the day and where you are, the swings are not
>> symmetrical around 0.0
>> 
>> Solid earth tides are a BIG factor in precision geodesy.   Gravity offset
>> is a big issue for precision pendulum nuts.  If your pendulum clock cannot
>> detect gravity offsets (very few can) it's not nutty enough.
>> 
>> The attached plot shows around 5 days of data.
>> 
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Re: [time-nuts] GPS Antenna on Tower.

[Peter Vince]

Hi Mark,

 This is all new information to me - and fascinating!  Have you just
"calculated" the offsets (using known values from somewhere), or "measured"
it by very long term averaging of the GPS position information?

 Peter Vince


On 20 June 2017 at 17:34, Mark Sims  wrote:

> I just added the ability to calculate solid earth tides and the vertical
> gravity offset due to the sun and moon to Lady Heather.   The lat/lon
> offset is typically around +/- 60 cm per day.Vertical offset is around
> +/- 180mm.  Depending upon the day and where you are, the swings are not
> symmetrical around 0.0
>
> Solid earth tides are a BIG factor in precision geodesy.   Gravity offset
> is a big issue for precision pendulum nuts.  If your pendulum clock cannot
> detect gravity offsets (very few can) it's not nutty enough.
>
> The attached plot shows around 5 days of data.
>
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[time-nuts] GPS Antenna on Tower.

[Mark Sims]

I just added the ability to calculate solid earth tides and the vertical 
gravity offset due to the sun and moon to Lady Heather.   The lat/lon offset is 
typically around +/- 60 cm per day.Vertical offset is around  +/- 180mm.  
Depending upon the day and where you are, the swings are not symmetrical around 
0.0   

Solid earth tides are a BIG factor in precision geodesy.   Gravity offset is a 
big issue for precision pendulum nuts.  If your pendulum clock cannot detect 
gravity offsets (very few can) it's not nutty enough.

The attached plot shows around 5 days of data.

---

>  Since 1cm of motion is equivalent to 30ps, there's probably not
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Re: [time-nuts] GPS Antenna on Tower.

[Bryan _]

I have wondered how geologists are able to measure tectonic plate movements in 
the earths surface to a couple cm's when the sensors from what I see/read they 
are nothing more than sensors in concrete boxes?. I believe they use various 
technologies such as Very Long Baseline 
Interferometry<http://www.see.leeds.ac.uk/structure/dynamicearth/plates_move/active_tectonics/vlbi.htm>
 (VLBI) and Satellite Laser 
Ranging<http://www.see.leeds.ac.uk/structure/dynamicearth/plates_move/active_tectonics/slr1.htm>
 (SLR)


All fascinating stuff




-=Bryan=-



From: time-nuts  on behalf of Thorbjørn Pedersen 

Sent: June 19, 2017 9:42 PM
To: time-nuts@febo.com
Subject: Re: [time-nuts] GPS Antenna on Tower.

http://www.sp.se/en/index/resources/GNSS/Sidor/default.aspx
[http://www.sp.se/sv/index/resources/GNSS/PublishingImages/pelare.jpg]<http://www.sp.se/en/index/resources/GNSS/Sidor/default.aspx>

GNSS-equipment - SP<http://www.sp.se/en/index/resources/GNSS/Sidor/default.aspx>
www.sp.se
GNSS-equipment RISE has equipment for GNSS (Global Navigation Satellite 
Systems) for applications in Time and Frequency, Positioning and Atmospheric 
Studies.



Have a look at the best receiving antenna I know about.

The tower must have cooling tubes coiled around it because of the sun heating 
one side will make it bend away from the sun, and turn this way all day.
The cable and doom is also temperature controlled.

Best Regards

Thorbjørn W. Pedersen


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time-nuts is a low volume, high SNR list for the discussion of precise time and 
frequency measurement and related topics. To see the collection of prior 
postings to ...



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Re: [time-nuts] GPS Antenna on Tower.

[Clay Autery]

I thought there was kind of a rule about EXCLUDING sats on or near the
horizon...

__
Clay Autery, KY5G

On 6/20/2017 8:27 AM, "Björn Gabrielsson" wrote:
> Hi Thorbjörn,
>
> To bad this particula antenna has surrounding buildings (and maybe trees)
> that mask low elevation satellites.
>
> --
>
>Björn
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Re: [time-nuts] GPS Antenna on Tower.

[Björn Gabrielsson]

Hi Thorbjörn,

To bad this particula antenna has surrounding buildings (and maybe trees)
that mask low elevation satellites.

--

   Björn

> http://www.sp.se/en/index/resources/GNSS/Sidor/default.aspx
> Have a look at the best receiving antenna I know about.
>
> The tower must have cooling tubes coiled around it because of the sun
> heating one side will make it bend away from the sun, and turn this way
> all day.
> The cable and doom is also temperature controlled.
>
> Best Regards
>
> Thorbjørn W. Pedersen
>
>
> ___
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Re: [time-nuts] GPS Antenna on Tower.

[Michael Wouters]

Try again ...,

Since 1cm of motion is equivalent to 30 ps, there's probably not much point
in putting your GNSS antenna on a geodetic monument if all you care about
is timing. But it does matter if you're trying to track continental drift.

Michael

On Tue, 20 Jun 2017 at 10:44 pm, Michael Wouters 
wrote:

> Since 1cm of motion is equivalent to 30ps, there's probably not
>
> On Tue, 20 Jun 2017 at 10:11 pm, Didier Juges  wrote:
>
>> If that is not time-nutty, I do not know what will :)
>>
>> On Jun 20, 2017 7:04 AM, "jimlux"  wrote:
>>
>> >
>> > for geodetic measurements, they drill a hole down to bedrock, and run a
>> > pipe down to anchor the antenna to the bedrock.
>> >
>> > "All holes shall be drilled straight enough so that PVC casing can be
>> > installed in the top 15.5 ft of each hole, and that the steel pipe can
>> be
>> > freely lowered, not forced, for its entire 35 ft length."
>> >
>> > http://kb.unavco.org/kb/article/deep-drilled-braced-monument
>> > -overview-300.html
>> > http://www.scign.org/arch/sdb_monument.htm
>> >
>> >
>> > Google for Ken Hudnutt's or Frank Webb's papers
>> >
>> >
>> > or a 3m tall monument for a CORS station
>> >
>> > http://www.mwrtk.net/support_docs/corsinstallprocedures.pdf
>> >
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>> > ailman/listinfo/time-nuts
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Re: [time-nuts] GPS Antenna on Tower.

[Michael Wouters]

Since 1cm of motion is equivalent to 30ps, there's probably not

On Tue, 20 Jun 2017 at 10:11 pm, Didier Juges  wrote:

> If that is not time-nutty, I do not know what will :)
>
> On Jun 20, 2017 7:04 AM, "jimlux"  wrote:
>
> >
> > for geodetic measurements, they drill a hole down to bedrock, and run a
> > pipe down to anchor the antenna to the bedrock.
> >
> > "All holes shall be drilled straight enough so that PVC casing can be
> > installed in the top 15.5 ft of each hole, and that the steel pipe can be
> > freely lowered, not forced, for its entire 35 ft length."
> >
> > http://kb.unavco.org/kb/article/deep-drilled-braced-monument
> > -overview-300.html
> > http://www.scign.org/arch/sdb_monument.htm
> >
> >
> > Google for Ken Hudnutt's or Frank Webb's papers
> >
> >
> > or a 3m tall monument for a CORS station
> >
> > http://www.mwrtk.net/support_docs/corsinstallprocedures.pdf
> >
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Re: [time-nuts] GPS Antenna on Tower.

[Wes]

It was bright sunshine and 46 degrees C here in the desert near Tucson, Arizona 
yesterday.  It would take a lot of cooling to keep that solar collector (radome) 
cool.


Wes Stewart

 On 6/19/2017 9:42 PM, Thorbjørn Pedersen wrote:

http://www.sp.se/en/index/resources/GNSS/Sidor/default.aspx
Have a look at the best receiving antenna I know about.

The tower must have cooling tubes coiled around it because of the sun heating 
one side will make it bend away from the sun, and turn this way all day.
The cable and doom is also temperature controlled.

Best Regards

Thorbjørn W. Pedersen


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Re: [time-nuts] GPS Antenna on Tower.

[Clay Autery]

LOL!!!  My first reaction to reading the drill for sub-subterranean GPS
mast was...

Wonder if I could borrow Shappell's little drilling rig to do THAT hole
and the vertical wells for the geo-thermal cooling loops?

Followed closely by...

Wonder what kind and number of Sorbothan, et al. dampers required to
damp the locally generated vibrations that would resonate in that length
"tuning fork" hooked to the bedrock?

  Even we non-scientists on this reflector reserve the right
to be equally nutty.  

PS - I have a master map of my back yard in order to manage the
available square footage and its use and to de-conflict the
sub-subterranean "air space".

__
Clay Autery, KY5G

On 6/20/2017 7:21 AM, jimlux wrote:
> On 6/20/17 5:11 AM, Didier Juges wrote:
>> If that is not time-nutty, I do not know what will :)
>
> if you're a "real time-nut" you drill your own holes - you buy a
> surplus drilling rig, refurbish it, figure out how to work it (maybe
> there's a "drill-nuts" list?), etc.
>
> But at least the station will probably fit in your backyard.
>

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Re: [time-nuts] GPS Antenna on Tower.

[jimlux]

On 6/20/17 5:11 AM, Didier Juges wrote:

If that is not time-nutty, I do not know what will :)


if you're a "real time-nut" you drill your own holes - you buy a surplus 
drilling rig, refurbish it, figure out how to work it (maybe there's a 
"drill-nuts" list?), etc.


But at least the station will probably fit in your backyard.



On Jun 20, 2017 7:04 AM, "jimlux"  wrote:



for geodetic measurements, they drill a hole down to bedrock, and run a
pipe down to anchor the antenna to the bedrock.

"All holes shall be drilled straight enough so that PVC casing can be
installed in the top 15.5 ft of each hole, and that the steel pipe can be
freely lowered, not forced, for its entire 35 ft length."

http://kb.unavco.org/kb/article/deep-drilled-braced-monument
-overview-300.html
http://www.scign.org/arch/sdb_monument.htm


Google for Ken Hudnutt's or Frank Webb's papers


or a 3m tall monument for a CORS station

http://www.mwrtk.net/support_docs/corsinstallprocedures.pdf

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Re: [time-nuts] GPS Antenna on Tower.

[Didier Juges]

If that is not time-nutty, I do not know what will :)

On Jun 20, 2017 7:04 AM, "jimlux"  wrote:

>
> for geodetic measurements, they drill a hole down to bedrock, and run a
> pipe down to anchor the antenna to the bedrock.
>
> "All holes shall be drilled straight enough so that PVC casing can be
> installed in the top 15.5 ft of each hole, and that the steel pipe can be
> freely lowered, not forced, for its entire 35 ft length."
>
> http://kb.unavco.org/kb/article/deep-drilled-braced-monument
> -overview-300.html
> http://www.scign.org/arch/sdb_monument.htm
>
>
> Google for Ken Hudnutt's or Frank Webb's papers
>
>
> or a 3m tall monument for a CORS station
>
> http://www.mwrtk.net/support_docs/corsinstallprocedures.pdf
>
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Re: [time-nuts] GPS Antenna on Tower.

[jimlux]

for geodetic measurements, they drill a hole down to bedrock, and run a 
pipe down to anchor the antenna to the bedrock.


"All holes shall be drilled straight enough so that PVC casing can be 
installed in the top 15.5 ft of each hole, and that the steel pipe can 
be freely lowered, not forced, for its entire 35 ft length."


http://kb.unavco.org/kb/article/deep-drilled-braced-monument-overview-300.html
http://www.scign.org/arch/sdb_monument.htm


Google for Ken Hudnutt's or Frank Webb's papers


or a 3m tall monument for a CORS station

http://www.mwrtk.net/support_docs/corsinstallprocedures.pdf

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Re: [time-nuts] GPS Antenna on Tower.

[Thorbjørn Pedersen]

http://www.sp.se/en/index/resources/GNSS/Sidor/default.aspx
Have a look at the best receiving antenna I know about.

The tower must have cooling tubes coiled around it because of the sun heating 
one side will make it bend away from the sun, and turn this way all day.
The cable and doom is also temperature controlled.

Best Regards

Thorbjørn W. Pedersen


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Re: [time-nuts] GPS Antenna on Tower.

[Attila Kinali]

On Mon, 19 Jun 2017 08:52:37 -0400
Dan Kemppainen  wrote:

> So, what sorts of things are done for high precision survey work? I 
> would guess a sturdy mount, good sky view, no reflections, good antenna, 
> no nearby radiators, etc. Those all seem like common sense stuff.

I don't know about survey work, but you can have a look at the EUREF[1]
stations. Most (all?) stations in the list[2] have pictures.

[1] https://en.wikipedia.org/wiki/EUREF_Permanent_Network
[2] http://www.epncb.oma.be/_networkdata/stationlist.php

> But for applications that really matter, what sorts of things might be 
> missing above. Obviously, really expensive silly things won't be done on 
> my site for a few GPSDO's, but it would be good to know what the issues 
> are.

You try to mount the antenna as sturdy as possible. The best is if
you have an open and level field and can put a nice block of concrete on
unmoving bedrock. If not, ontop of a well build building will do,
though the vibrations might not be negligible. People use also relatively
low towers (high towers tend to vibrate), of only 2-5m height. Again mounted
on a block of concrete, if the tower isn't itself a construction made
of concrete. The dome should be such, that you don't get a bird problem
and that snow does not stick. At the same time the dome should be
shaped in a way that does not cause any refraction. If your reference
station (which is in a nearby building in a temperature controlled room)
has any ultra stable reference oscillator (think of a Cs beam standard
or a hydrogen maser), then you also want to have the temperature and
humidity of the cable going to the antenna controlled. Ie. you put
the antenna cable into a tube and blow constant temperature/humidity
air through it.

Of course you can go even more crazy, but the temperature/humidity controlled
cable is about the most extreme I have heard of.


Attila Kinali
-- 
It is upon moral qualities that a society is ultimately founded. All 
the prosperity and technological sophistication in the world is of no 
use without that foundation.
 -- Miss Matheson, The Diamond Age, Neil Stephenson
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Re: [time-nuts] GPS Antenna on Tower.

[Bob kb8tq]

Hi

If you go totally insane, you build a 30’ tall concrete monolith in the middle 
of a wide open field. The antenna
and ground plane go on top of the monolith. You then grab your chain saw and 
start knocking down any trees,
towers, or homes that happen to obstruct your perfect view. :) Indeed this is a 
bit easier if you have a nice big 
budget and can buy (or already own) a giant open chunk of land already. Ex-air 
bases seem to be an excellent 
candidate. 

Bob

> On Jun 19, 2017, at 8:52 AM, Dan Kemppainen  wrote:
> 
> Hi Bob,
> 
> So, what sorts of things are done for high precision survey work? I would 
> guess a sturdy mount, good sky view, no reflections, good antenna, no nearby 
> radiators, etc. Those all seem like common sense stuff.
> 
> But for applications that really matter, what sorts of things might be 
> missing above. Obviously, really expensive silly things won't be done on my 
> site for a few GPSDO's, but it would be good to know what the issues are.
> 
> Thanks,
> Dan
> 
> 
> 
> On 6/16/2017 6:29 PM, time-nuts-requ...@febo.com wrote:
>> 
>> Hi
>> 
>> Will there be an effect? Yes. Are roughly 99% of all GPSDO’s run with 
>> antennas mounted that way
>> by “pros” ? Yes again.
>> 
>> If you are setting up a reference site for high precision survey work, don’t 
>> do it that way. For a GPSDO,
>> you should be fine.
>> 
>> Bob
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Re: [time-nuts] GPS Antenna on Tower.

[Dan Kemppainen]

Hi Bob,

So, what sorts of things are done for high precision survey work? I 
would guess a sturdy mount, good sky view, no reflections, good antenna, 
no nearby radiators, etc. Those all seem like common sense stuff.


But for applications that really matter, what sorts of things might be 
missing above. Obviously, really expensive silly things won't be done on 
my site for a few GPSDO's, but it would be good to know what the issues 
are.


Thanks,
Dan



On 6/16/2017 6:29 PM, time-nuts-requ...@febo.com wrote:


Hi

Will there be an effect? Yes. Are roughly 99% of all GPSDO’s run with antennas 
mounted that way
by “pros” ? Yes again.

If you are setting up a reference site for high precision survey work, don’t do 
it that way. For a GPSDO,
you should be fine.

Bob

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Re: [time-nuts] GPS Antenna on Tower.

[paul swed]

Good comments by Bob.
I run 100 ft of Rohn 45 and then have a stack of rotatable antennas at that
point.
I have the antenna some 3-4 ft off the tower at 90' feeding with 1/2"
line.(Because I had it) The trees have grown to 90' so that gives a nice
clean view south. Works totally fine. Reason to keep it a bit lower is to
allow other things to take the static that can build up. Most of the other
stuff is just metal.
I also have a backup antenna at the 50' level using 75 ohm hardline.
the great thing today is just about anything works pretty well.
Regards
Paul.
WB8TSL

On Fri, Jun 16, 2017 at 2:38 PM, Bob kb8tq  wrote:

> Hi
>
> Will there be an effect? Yes. Are roughly 99% of all GPSDO’s run with
> antennas mounted that way
> by “pros” ? Yes again.
>
> If you are setting up a reference site for high precision survey work,
> don’t do it that way. For a GPSDO,
> you should be fine.
>
> Bob
>
> > On Jun 16, 2017, at 1:17 PM, Dan Kemppainen 
> wrote:
> >
> > Hi All,
> >
> > Fair Warning: Nuts Mode Engaged.  :)
> >
> >
> > Recently we've moved to a new house and am in the process of getting the
> antennas back up for various things. One of these is the GPSDO(s), and an
> obvious location is somewhere on a Roan 25 tower set up just south of the
> house. At about half way up the tower, there is clear sky view in all
> directions and the GPS antenna is temporarily parked there about a foot off
> the tower. The GPS antenna is on the south side of the tower and we're
> ~47N, so most of the GPS birds should be visible. Single band GPS antenna,
> nothing special.
> >
> > My guess is this will be fine. However, I'm still wondering what sorts
> of multi-path or reflections could be expected off the tower itself. And
> are these enough to worry about? If there is multi-path what sorts of
> things would help prevent this? (Mounting the antenna further off the
> tower, etc.)
> >
> > Once I get the tower guy lines redone, I'm thinking about putting the
> GPS antenna on the tip of the mast (No rotator on this tower). That's at
> about 75 feet with nothing close by. That would be slightly above the tree
> line, with a 360 degree sky view.
> >
> > FYI, currently the GPS antenna wire is "Priority Wire and Cable" RG-6/U.
> Did some measurements last night. It measures as 85 Ohm, with a velocity
> factor of ~.86. It looks pretty lossy, but it should still work.
> >
> > Any ideas and comments welcome!
> >
> > Thanks,
> > Dan
> >
> > ___
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> mailman/listinfo/time-nuts
> > and follow the instructions there.
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Re: [time-nuts] GPS Antenna on Tower.

[Bob kb8tq]

Hi

Will there be an effect? Yes. Are roughly 99% of all GPSDO’s run with antennas 
mounted that way
by “pros” ? Yes again. 

If you are setting up a reference site for high precision survey work, don’t do 
it that way. For a GPSDO,
you should be fine.

Bob

> On Jun 16, 2017, at 1:17 PM, Dan Kemppainen  wrote:
> 
> Hi All,
> 
> Fair Warning: Nuts Mode Engaged.  :)
> 
> 
> Recently we've moved to a new house and am in the process of getting the 
> antennas back up for various things. One of these is the GPSDO(s), and an 
> obvious location is somewhere on a Roan 25 tower set up just south of the 
> house. At about half way up the tower, there is clear sky view in all 
> directions and the GPS antenna is temporarily parked there about a foot off 
> the tower. The GPS antenna is on the south side of the tower and we're ~47N, 
> so most of the GPS birds should be visible. Single band GPS antenna, nothing 
> special.
> 
> My guess is this will be fine. However, I'm still wondering what sorts of 
> multi-path or reflections could be expected off the tower itself. And are 
> these enough to worry about? If there is multi-path what sorts of things 
> would help prevent this? (Mounting the antenna further off the tower, etc.)
> 
> Once I get the tower guy lines redone, I'm thinking about putting the GPS 
> antenna on the tip of the mast (No rotator on this tower). That's at about 75 
> feet with nothing close by. That would be slightly above the tree line, with 
> a 360 degree sky view.
> 
> FYI, currently the GPS antenna wire is "Priority Wire and Cable" RG-6/U. Did 
> some measurements last night. It measures as 85 Ohm, with a velocity factor 
> of ~.86. It looks pretty lossy, but it should still work.
> 
> Any ideas and comments welcome!
> 
> Thanks,
> Dan
> 
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[time-nuts] GPS Antenna on Tower.

[Dan Kemppainen]

Hi All,

Fair Warning: Nuts Mode Engaged.  :)


Recently we've moved to a new house and am in the process of getting the 
antennas back up for various things. One of these is the GPSDO(s), and 
an obvious location is somewhere on a Roan 25 tower set up just south of 
the house. At about half way up the tower, there is clear sky view in 
all directions and the GPS antenna is temporarily parked there about a 
foot off the tower. The GPS antenna is on the south side of the tower 
and we're ~47N, so most of the GPS birds should be visible. Single band 
GPS antenna, nothing special.


My guess is this will be fine. However, I'm still wondering what sorts 
of multi-path or reflections could be expected off the tower itself. And 
are these enough to worry about? If there is multi-path what sorts of 
things would help prevent this? (Mounting the antenna further off the 
tower, etc.)


Once I get the tower guy lines redone, I'm thinking about putting the 
GPS antenna on the tip of the mast (No rotator on this tower). That's at 
about 75 feet with nothing close by. That would be slightly above the 
tree line, with a 360 degree sky view.


FYI, currently the GPS antenna wire is "Priority Wire and Cable" RG-6/U. 
Did some measurements last night. It measures as 85 Ohm, with a velocity 
factor of ~.86. It looks pretty lossy, but it should still work.


Any ideas and comments welcome!

Thanks,
Dan

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Re: [time-nuts] GPS? Antenna

[Glenn Little WB4UIV]

Thanks for all of the help.
I contacted Huber Suhner and now have the data sheet and radiation 
patterns for this antenna.


73
Glenn
WB4UIV



On 9/6/2016 4:25 AM, Szeker K. wrote:

Yes its H-S model, and it must be a GPS antenna...
http://www.cafr.ebay.ca/itm/Ericsson-KRE-1012082-1-GPS-Antenna-26dBi-For-HUBER-SUHNER-84097323-/182012930579?hash=item2a60d0ea13:g:MAMAAOSwZd1Vdn6-
Regards
Karl

2016-09-06 5:12 GMT+02:00 Chris Waldrup :


It's a Huber Suhner.

Chris


On Sep 5, 2016, at 21:26, Glenn Little WB4UIV <

glennmaill...@bellsouth.net> wrote:


Pete,

I do not know if I can send a picture to the mailing list.

I am sending this to you and the list.

The antenna is 4 inches from tip of cone to bottom of type-N connector.
It is 2 5/8" in diameter.

Thanks
Glenn




On 9/5/2016 8:25 PM, Pete Lancashire wrote:
Nemko is the Norwegian "UL", my guess is the numbers are the
test/certification numbers. A picture would help

-pete

On Mon, Sep 5, 2016 at 5:14 PM, Glenn Little WB4UIV
mailto:glennmaill...@bellsouth.net>>

wrote:


   At the last hamfest that I attended, I bought an antenna that looks
   like a GPS antenna.
   The price was right.
   This is a Nemko Article number: 84097323, Type number 1315.17.0018.
   It has a manufacturing date of 09/2012.
   Can anyone tell me if this is in fact a GPS antenna and what voltage
   wold be required.
   I would suspect that it would be either 5VDC or 3.3 VDC based on the
   date.
   Any help appreciated.

   Thanks
   73
   Glenn
   WB4UIV

   --
   

---

   Glenn LittleARRL Technical Specialist   QCWA  LM

28417

   Amateur Callsign:  WB4UIVwb4...@arrl.net
   AMSAT LM 2178
   QTH:  Goose Creek, SC USA (EM92xx)  USSVI LM   NRA LM   SBE ARRL TAPR
   "It is not the class of license that the Amateur holds but the class
   of the Amateur that holds the license"
   

---

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time-nuts@febo.com>

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--
---
Glenn LittleARRL Technical Specialist   QCWA  LM 28417
Amateur Callsign:  WB4UIVwb4...@arrl.netAMSAT LM 2178
QTH:  Goose Creek, SC USA (EM92xx)  USSVI LM   NRA LM   SBE ARRL TAPR
"It is not the class of license that the Amateur holds but the class
of the Amateur that holds the license"


---


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--
---
Glenn LittleARRL Technical Specialist   QCWA  LM 28417
Amateur Callsign:  WB4UIVwb4...@arrl.netAMSAT LM 2178
QTH:  Goose Creek, SC USA (EM92xx)  USSVI LM   NRA LM   SBE ARRL TAPR
"It is not the class of license that the Amateur holds but the class
of the Amateur that holds the license"
---
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Re: [time-nuts] GPS? Antenna

[Szeker K.]

Yes its H-S model, and it must be a GPS antenna...
http://www.cafr.ebay.ca/itm/Ericsson-KRE-1012082-1-GPS-Antenna-26dBi-For-HUBER-SUHNER-84097323-/182012930579?hash=item2a60d0ea13:g:MAMAAOSwZd1Vdn6-
Regards
Karl

2016-09-06 5:12 GMT+02:00 Chris Waldrup :

> It's a Huber Suhner.
>
> Chris
>
> > On Sep 5, 2016, at 21:26, Glenn Little WB4UIV <
> glennmaill...@bellsouth.net> wrote:
> >
> > Pete,
> >
> > I do not know if I can send a picture to the mailing list.
> >
> > I am sending this to you and the list.
> >
> > The antenna is 4 inches from tip of cone to bottom of type-N connector.
> > It is 2 5/8" in diameter.
> >
> > Thanks
> > Glenn
> >
> >
> >
> >> On 9/5/2016 8:25 PM, Pete Lancashire wrote:
> >> Nemko is the Norwegian "UL", my guess is the numbers are the
> >> test/certification numbers. A picture would help
> >>
> >> -pete
> >>
> >> On Mon, Sep 5, 2016 at 5:14 PM, Glenn Little WB4UIV
> >> mailto:glennmaill...@bellsouth.net>>
> wrote:
> >>
> >>At the last hamfest that I attended, I bought an antenna that looks
> >>like a GPS antenna.
> >>The price was right.
> >>This is a Nemko Article number: 84097323, Type number 1315.17.0018.
> >>It has a manufacturing date of 09/2012.
> >>Can anyone tell me if this is in fact a GPS antenna and what voltage
> >>wold be required.
> >>I would suspect that it would be either 5VDC or 3.3 VDC based on the
> >>date.
> >>Any help appreciated.
> >>
> >>Thanks
> >>73
> >>Glenn
> >>WB4UIV
> >>
> >>--
> >>
> ---
> >>Glenn LittleARRL Technical Specialist   QCWA  LM
> 28417
> >>Amateur Callsign:  WB4UIVwb4...@arrl.net
> >>AMSAT LM 2178
> >>QTH:  Goose Creek, SC USA (EM92xx)  USSVI LM   NRA LM   SBE ARRL TAPR
> >>"It is not the class of license that the Amateur holds but the class
> >>of the Amateur that holds the license"
> >>
> ---
> >>___
> >>time-nuts mailing list -- time-nuts@febo.com  time-nuts@febo.com>
> >>To unsubscribe, go to
> >>https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts
> >>
> >>and follow the instructions there.
> >
> > --
> > ---
> > Glenn LittleARRL Technical Specialist   QCWA  LM 28417
> > Amateur Callsign:  WB4UIVwb4...@arrl.netAMSAT LM 2178
> > QTH:  Goose Creek, SC USA (EM92xx)  USSVI LM   NRA LM   SBE ARRL TAPR
> > "It is not the class of license that the Amateur holds but the class
> > of the Amateur that holds the license"
> > 
> ---
> > 
> > ___
> > time-nuts mailing list -- time-nuts@febo.com
> > To unsubscribe, go to https://www.febo.com/cgi-bin/
> mailman/listinfo/time-nuts
> > and follow the instructions there.
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Re: [time-nuts] GPS Antenna?

[Gregory Beat]

Glenn -

These outdoor GPS antennas are PLENTIFUL via surplus.  Launch3, which offered 
NOS Symmetricom surplus antennas to this group 12 months ago, are now selling 
these surplus Ericsson KRE units (eBay).

The H inside a hexagon is the corporate logo for Huber-Suhner.
Huber is a Swiss HQ company.
http://www.hubersuhner.com/en/Products/Radio-Frequency/Antennas

This antenna, model 84097323, is listed under a variety of brand-names.
The Norwegian certification (Nemko) was likely for Ericsson KRE.

Do a Google search: "GPS Antenna 84097323" and you will find many "hits" from 
eBay and surplus resellers.

w9gb
Original Message
At the last hamfest that I attended, I bought an antenna that looks like 
a GPS antenna.  The price was right.
This is a Nemko Article number: 84097323, Type number 1315.17.0018.
It has a manufacturing date of 09/2012.
Can anyone tell me if this is in fact a GPS antenna and what voltage 
would be required.
I would suspect that it would be either 5VDC or 3.3 VDC based on the date.
Any help appreciated.
Thanks, 73
Glenn, WB4UIV
  

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Re: [time-nuts] GPS? Antenna

[Chris Waldrup]

It's a Huber Suhner. 

Chris

> On Sep 5, 2016, at 21:26, Glenn Little WB4UIV  
> wrote:
> 
> Pete,
> 
> I do not know if I can send a picture to the mailing list.
> 
> I am sending this to you and the list.
> 
> The antenna is 4 inches from tip of cone to bottom of type-N connector.
> It is 2 5/8" in diameter.
> 
> Thanks
> Glenn
> 
> 
> 
>> On 9/5/2016 8:25 PM, Pete Lancashire wrote:
>> Nemko is the Norwegian "UL", my guess is the numbers are the
>> test/certification numbers. A picture would help
>> 
>> -pete
>> 
>> On Mon, Sep 5, 2016 at 5:14 PM, Glenn Little WB4UIV
>> mailto:glennmaill...@bellsouth.net>> wrote:
>> 
>>At the last hamfest that I attended, I bought an antenna that looks
>>like a GPS antenna.
>>The price was right.
>>This is a Nemko Article number: 84097323, Type number 1315.17.0018.
>>It has a manufacturing date of 09/2012.
>>Can anyone tell me if this is in fact a GPS antenna and what voltage
>>wold be required.
>>I would suspect that it would be either 5VDC or 3.3 VDC based on the
>>date.
>>Any help appreciated.
>> 
>>Thanks
>>73
>>Glenn
>>WB4UIV
>> 
>>--
>>---
>>Glenn LittleARRL Technical Specialist   QCWA  LM 28417
>>Amateur Callsign:  WB4UIVwb4...@arrl.net
>>AMSAT LM 2178
>>QTH:  Goose Creek, SC USA (EM92xx)  USSVI LM   NRA LM   SBE ARRL TAPR
>>"It is not the class of license that the Amateur holds but the class
>>of the Amateur that holds the license"
>>
>> ---
>>___
>>time-nuts mailing list -- time-nuts@febo.com 
>>To unsubscribe, go to
>>https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts
>>
>>and follow the instructions there.
> 
> -- 
> ---
> Glenn LittleARRL Technical Specialist   QCWA  LM 28417
> Amateur Callsign:  WB4UIVwb4...@arrl.netAMSAT LM 2178
> QTH:  Goose Creek, SC USA (EM92xx)  USSVI LM   NRA LM   SBE ARRL TAPR
> "It is not the class of license that the Amateur holds but the class
> of the Amateur that holds the license"
> ---
> 
> ___
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Re: [time-nuts] GPS? Antenna

[Pete Lancashire]

Nemko is the Norwegian "UL", my guess is the numbers are the
test/certification numbers. A picture would help

-pete

On Mon, Sep 5, 2016 at 5:14 PM, Glenn Little WB4UIV <
glennmaill...@bellsouth.net> wrote:

> At the last hamfest that I attended, I bought an antenna that looks like a
> GPS antenna.
> The price was right.
> This is a Nemko Article number: 84097323, Type number 1315.17.0018.
> It has a manufacturing date of 09/2012.
> Can anyone tell me if this is in fact a GPS antenna and what voltage wold
> be required.
> I would suspect that it would be either 5VDC or 3.3 VDC based on the date.
> Any help appreciated.
>
> Thanks
> 73
> Glenn
> WB4UIV
>
> --
> ---
> Glenn LittleARRL Technical Specialist   QCWA  LM 28417
> Amateur Callsign:  WB4UIVwb4...@arrl.netAMSAT LM 2178
> QTH:  Goose Creek, SC USA (EM92xx)  USSVI LM   NRA LM   SBE ARRL TAPR
> "It is not the class of license that the Amateur holds but the class
> of the Amateur that holds the license"
> 
> ---
> ___
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> To unsubscribe, go to https://www.febo.com/cgi-bin/m
> ailman/listinfo/time-nuts
> and follow the instructions there.
>
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[time-nuts] GPS? Antenna

[Glenn Little WB4UIV]

At the last hamfest that I attended, I bought an antenna that looks like 
a GPS antenna.

The price was right.
This is a Nemko Article number: 84097323, Type number 1315.17.0018.
It has a manufacturing date of 09/2012.
Can anyone tell me if this is in fact a GPS antenna and what voltage 
wold be required.

I would suspect that it would be either 5VDC or 3.3 VDC based on the date.
Any help appreciated.

Thanks
73
Glenn
WB4UIV

--
---
Glenn LittleARRL Technical Specialist   QCWA  LM 28417
Amateur Callsign:  WB4UIVwb4...@arrl.netAMSAT LM 2178
QTH:  Goose Creek, SC USA (EM92xx)  USSVI LM   NRA LM   SBE ARRL TAPR
"It is not the class of license that the Amateur holds but the class
of the Amateur that holds the license"
---
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Re: [time-nuts] GPS antenna selection - lightning

[Bob Camp]

Hi

We tend to look at all this lighting / EMP stuff very much as a “get to the 
ground” 
sort of thing. For whatever reason the whole thought process stops once we get
to a coper weld rod driven however far into the dirt. 

If you try to operate a vertical antenna against that same rod in the middle of 
a nice dry
summer.  You will quickly find out that dirt != ground. The same fun and games
that get you a low impedance ground for your antenna also apply to a low 
impedance 
ground for your protection system. Its not an identical process, but it’s the 
same idea. 

You can argue that a good bond of everything to a single point is sufficient. 
Looking around
my house, there is most certainly *not* a single point of entry for everything. 
Various 
utilities and other wires / chunks of conductive stuff go off in a variety of 
directions. Like
most homes in the US, it’s a wood frame structure. There is no nice steel frame 
to 
tie everything to. I suppose the first step would be to tear the house down and 
re-build
it from scratch …..

Bob

> On Aug 8, 2016, at 10:00 AM, jimlux  wrote:
> 
> On 8/7/16 8:06 PM, Bill Hawkins wrote:
>> This thread grows old, so here's one person's summary:
>> Marine supply stores sell rolls of 4 inch
>> wide copper strap for connecting the mast on the wheelhouse cabin with
>> the keel of fiberglass boats. This is also the ground for all electronic
>> equipment. The strap is considerably less inductive than a wire.
> 
> No - strap is about the same inductance as a wire of the same length. The 
> advantage of strap is a lower RF resistance, which is important if the strap 
> is part of your antenna system, because it's less resistive loss than a wire.
> 
> For lightning impulses, either conducted or radiated, the inductance 
> dominates the voltage rise (e.g. Xl is much larger than Rac).
> 
> Strap or bar may be easier to make connections to (drill a hole in some 
> 1/8x1" bar, tap it, and hook your lug up)
> 
> 
> 
> 
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Re: [time-nuts] GPS antenna selection - lightning

[jimlux]

On 8/7/16 8:06 PM, Bill Hawkins wrote:

This thread grows old, so here's one person's summary:
 Marine supply stores sell rolls of 4 inch
wide copper strap for connecting the mast on the wheelhouse cabin with
the keel of fiberglass boats. This is also the ground for all electronic
equipment. The strap is considerably less inductive than a wire.


No - strap is about the same inductance as a wire of the same length. 
The advantage of strap is a lower RF resistance, which is important if 
the strap is part of your antenna system, because it's less resistive 
loss than a wire.


For lightning impulses, either conducted or radiated, the inductance 
dominates the voltage rise (e.g. Xl is much larger than Rac).


Strap or bar may be easier to make connections to (drill a hole in some 
1/8x1" bar, tap it, and hook your lug up)





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Re: [time-nuts] GPS antenna selection - lightning

[Bob Stewart]

Hi Bill,
A lot of us are hams.  The ARRL handbook has a section on grounds, including 
the need for bonding additional grounds to the power line ground.  A loop of 
heavy gauge wire around the house that has periodic 8' ground rods is seen as a 
good thing as long as it's bonded to the power line ground.  This is something 
entirely different from "multi-point ground".  It is said to provide a circle 
of protection around the house, but yea, it's a lot more complicated than that. 
 Check the handbook, or read whatever grounding documents you have access to 
and trust.

OK, I've had my say.

Bob - AE6RV
 -
AE6RV.com

GFS GPSDO list:
groups.yahoo.com/neo/groups/GFS-GPSDOs/info

  From: Bill Hawkins 
 To: 'Discussion of precise time and frequency measurement' 
 
 Sent: Sunday, August 7, 2016 10:06 PM
 Subject: Re: [time-nuts] GPS antenna selection - lightning
   
This thread grows old, so here's one person's summary:

There are two ways to be damaged by lightning:

1. A direct hit pumps 100 kiloamps of electrons into an ohm or so of
your local wiring. There is no way to survive a direct hit except to
implement stuff only the Military can afford. The probability is so low
(outside of Florida and mountain tops) that your homeowners insurance
may cover it.

2. A 100 KA strike goes to ground near you, with two effects:
  a. The ground resistance allows a large range of volts per meter to
kill cows but not golfers with their feet together.
  b. A mighty electromagnetic pulse (EMP) induces voltages in anything
inductive that is not shielded or twisted.

Case 'a' argues for a single point earth ground. When the ground voltage
goes up, you want all of your equipment to go up with it, as if it was
on an isolated ground plane. It seems best to use the Electric Power
Company's house ground for that reference point in your home. If you use
a UPS for a set of equipment, everything on it should ground to that UPS
(which should have a high capacity surge arrestor). You are left with
telephone cords, TV cables, and antennas as peripheral connections to
protect with surge arrestors. Marine supply stores sell rolls of 4 inch
wide copper strap for connecting the mast on the wheelhouse cabin with
the keel of fiberglass boats. This is also the ground for all electronic
equipment. The strap is considerably less inductive than a wire.

Case 'b' argues against long wires inside the area that contains the
common ground and the surge arrestors at its periphery.
Surge arrestors have energy ratings that refer to the energy of the EMP
that caused the surge. I have no idea how that relates to lightning EMP
energy so I buy the most capacity I can afford.

I used these principles in a home that had a pair of HP GPS antennas
four feet apart on a twenty foot mast of six inch plastic pipe, using N
connectors and 50 feet of RG-8 to a pair of Z3801A receivers. The
neighbor's tree took a direct hit (was split apart) less than 100 feet
away. He had extensive electrical damage originating at the outdoor
flood light six feet from the tree. I lost the GPS antenna closest to
the tree but nothing else. FWIW, I had wireless G access points
separating the area connected to the antenna from the rest of the house
network. No attempt was made to beef up the grounds.

Regards,
Bill Hawkins

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Re: [time-nuts] GPS antenna selection - lightning

[Bill Hawkins]

This thread grows old, so here's one person's summary:

There are two ways to be damaged by lightning:

1. A direct hit pumps 100 kiloamps of electrons into an ohm or so of
your local wiring. There is no way to survive a direct hit except to
implement stuff only the Military can afford. The probability is so low
(outside of Florida and mountain tops) that your homeowners insurance
may cover it.

2. A 100 KA strike goes to ground near you, with two effects:
  a. The ground resistance allows a large range of volts per meter to
kill cows but not golfers with their feet together.
  b. A mighty electromagnetic pulse (EMP) induces voltages in anything
inductive that is not shielded or twisted.

Case 'a' argues for a single point earth ground. When the ground voltage
goes up, you want all of your equipment to go up with it, as if it was
on an isolated ground plane. It seems best to use the Electric Power
Company's house ground for that reference point in your home. If you use
a UPS for a set of equipment, everything on it should ground to that UPS
(which should have a high capacity surge arrestor). You are left with
telephone cords, TV cables, and antennas as peripheral connections to
protect with surge arrestors. Marine supply stores sell rolls of 4 inch
wide copper strap for connecting the mast on the wheelhouse cabin with
the keel of fiberglass boats. This is also the ground for all electronic
equipment. The strap is considerably less inductive than a wire.

Case 'b' argues against long wires inside the area that contains the
common ground and the surge arrestors at its periphery.
Surge arrestors have energy ratings that refer to the energy of the EMP
that caused the surge. I have no idea how that relates to lightning EMP
energy so I buy the most capacity I can afford.

I used these principles in a home that had a pair of HP GPS antennas
four feet apart on a twenty foot mast of six inch plastic pipe, using N
connectors and 50 feet of RG-8 to a pair of Z3801A receivers. The
neighbor's tree took a direct hit (was split apart) less than 100 feet
away. He had extensive electrical damage originating at the outdoor
flood light six feet from the tree. I lost the GPS antenna closest to
the tree but nothing else. FWIW, I had wireless G access points
separating the area connected to the antenna from the rest of the house
network. No attempt was made to beef up the grounds.

Regards,
Bill Hawkins

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Re: [time-nuts] GPS antenna selection - lightning

[Chris Albertson]

On Sat, Aug 6, 2016 at 12:53 PM, Glenn Little WB4UIV <
glennmaill...@bellsouth.net> wrote:

> The latest that I can find is 1987.
> If you understand the theory and practice, you do not have to update your
> work often.
> It is the works that are updated every few months that you have to worry
> about. The did not get it right the first time.


You got that right.   For something as simple as grounding a small antenna
mast if you follow Ben Franklin's advice you will have about the same thing
as what is recommended today.Same for Newton and Einstein for 99% of
the stuff you do every day Newton got it right.

A lot of the exotic methods invented recently to protect electronics would
not apply to protecting a $50 receiver you bought on eBay or even a $1000
unit.  For example the first thing I would need to do is run a ring of 00
size wire around my house and fuse the various grounds to it.  But the cost
of having the trench dug (before even buying the wire) exceeds the cost of
the equipment it would protect.  TV sets are only $300 today.So most of
us about $10 worth of protection (a coax ground block and #12 bare wire)
and buy insurance.
-- 

Chris Albertson
Redondo Beach, California
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Re: [time-nuts] GPS antenna selection - lightning

[Glenn Little WB4UIV]

The latest that I can find is 1987.
If you understand the theory and practice, you do not have to update 
your work often.
It is the works that are updated every few months that you have to worry 
about. The did not get it right the first time.


This is still an active military document.

73
Glenn
WB4UIV

On 8/6/2016 1:13 PM, Chris Albertson wrote:

If you are looking for info in lightening.  University of Florida has a
huge collection and also points to many other places on the web.   They
actually do testing there, lightening occurs so reliably almost every day
in summer.  Their test tower gets many hits
http://www.lightning.ece.ufl.edu

But really, for practical purposes Ben Franklin got it pretty close to
right.  Give the lightening a good low impedance path to ground.

On Sat, Aug 6, 2016 at 8:00 AM, Clay Autery  wrote:


Is the 1987 version the latest issue available for free?

__
Clay Autery, KY5G
MONTAC Enterprises
(318) 518-1389

On 8/6/2016 8:46 AM, Glenn Little WB4UIV wrote:

Cone of protection is addressed.
Volume 1 is theory, volume 2 is application.
The military requires 1/0 cable exterior to the building, commercial
practice is #2AWG.
Ground rod spacing is address.

Overall a very good reference based on practical experience and backed
with theory.

73
Glenn
WB4UIV


On 8/6/2016 1:19 AM, Bill Hawkins wrote:

Hi Glenn,

Your advice is excellent.

Seems like every time we have a lightning discussion there is no
distinction between an EMP and a direct hit.

I started work in 1960 at a blasting cap plant in upstate New York. The
powder magazines were protected by tall masts according to the "cone of
protection" theory. The angle of the cone varied between 45 and 60
degrees. The earth ground resistance of the mast was measured by a
hand-cranked device that looked like a megger but read earth resistance
to less than a tenth of an ohm. Had the lightning but never lost a
magazine.

You say MIL-HDBK-419 covers EMP. Does it also cover cone of protection
for direct hits?

I was fascinated by the idea that a simple capacitor discharge into an
inductor could be greatly enhanced by reducing the diameter of the
inductor with a conventional explosive, described in one of Stephen
Coonts' books, if my failing memory recalls correctly. And so I learned
what I could about EMP. Never built anything, just interesting behavior.

Best regards,
Bill Hawkins


-Original Message-
From: time-nuts [mailto:time-nuts-boun...@febo.com] On Behalf Of Glenn
Little WB4UIV
Sent: Friday, August 05, 2016 9:47 PM
To: Discussion of precise time and frequency measurement
Subject: Re: [time-nuts]GPS antenna selection - lightning

A very good reference for EMP protection is MIL-HDBK-419.
This is downloadable for a number of web sources.
It is about 600 pages and is in two volumes.
This discusses a number of different sources of EMP such as nuclear and
lightning.
A lot is for protection of military industrial complexes, but, there is
a lot that pertains to us.

I worked for a military complex that assembled nuclear missiles.
The site was built to this handbook specs.
We had no EMP related damage at the site.

Number one rule, bond all grounds together. If something on your
property takes a hit, you want everything on your property to elevate to
the same level and the same rate.
If you have multiple, non bonded grounds, there is a different reference
for each ground. This is a major source for disaster.

I spent seven years in lightning mitigation. I was told by professionals
that I was wrong. The third time that their tower was struck, destroying
all of the lights and attached equipment, they followed my
recommendations. That was ten years ago. The three hits were within four
months of each other. The site has been free of destructive hits since
then.

73
Glenn
WB4UIV








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--
---
Glenn LittleARRL Technical Specialist   QCWA  LM 28417
Amateur Callsign:  WB4UIVwb4...@arrl.netAMSAT LM 2178
QTH:  Goose Creek, SC USA (EM92xx)  USSVI LM   NRA LM   SBE ARRL TAPR
"It is not the class of license that the Amateur holds but the class
of the Amateur that holds the license"
---
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Re: [time-nuts] GPS antenna selection - lightning

[Chris Albertson]

If you are looking for info in lightening.  University of Florida has a
huge collection and also points to many other places on the web.   They
actually do testing there, lightening occurs so reliably almost every day
in summer.  Their test tower gets many hits
http://www.lightning.ece.ufl.edu

But really, for practical purposes Ben Franklin got it pretty close to
right.  Give the lightening a good low impedance path to ground.

On Sat, Aug 6, 2016 at 8:00 AM, Clay Autery  wrote:

> Is the 1987 version the latest issue available for free?
>
> __
> Clay Autery, KY5G
> MONTAC Enterprises
> (318) 518-1389
>
> On 8/6/2016 8:46 AM, Glenn Little WB4UIV wrote:
> > Cone of protection is addressed.
> > Volume 1 is theory, volume 2 is application.
> > The military requires 1/0 cable exterior to the building, commercial
> > practice is #2AWG.
> > Ground rod spacing is address.
> >
> > Overall a very good reference based on practical experience and backed
> > with theory.
> >
> > 73
> > Glenn
> > WB4UIV
> >
> >
> > On 8/6/2016 1:19 AM, Bill Hawkins wrote:
> >> Hi Glenn,
> >>
> >> Your advice is excellent.
> >>
> >> Seems like every time we have a lightning discussion there is no
> >> distinction between an EMP and a direct hit.
> >>
> >> I started work in 1960 at a blasting cap plant in upstate New York. The
> >> powder magazines were protected by tall masts according to the "cone of
> >> protection" theory. The angle of the cone varied between 45 and 60
> >> degrees. The earth ground resistance of the mast was measured by a
> >> hand-cranked device that looked like a megger but read earth resistance
> >> to less than a tenth of an ohm. Had the lightning but never lost a
> >> magazine.
> >>
> >> You say MIL-HDBK-419 covers EMP. Does it also cover cone of protection
> >> for direct hits?
> >>
> >> I was fascinated by the idea that a simple capacitor discharge into an
> >> inductor could be greatly enhanced by reducing the diameter of the
> >> inductor with a conventional explosive, described in one of Stephen
> >> Coonts' books, if my failing memory recalls correctly. And so I learned
> >> what I could about EMP. Never built anything, just interesting behavior.
> >>
> >> Best regards,
> >> Bill Hawkins
> >>
> >>
> >> -Original Message-
> >> From: time-nuts [mailto:time-nuts-boun...@febo.com] On Behalf Of Glenn
> >> Little WB4UIV
> >> Sent: Friday, August 05, 2016 9:47 PM
> >> To: Discussion of precise time and frequency measurement
> >> Subject: Re: [time-nuts]GPS antenna selection - lightning
> >>
> >> A very good reference for EMP protection is MIL-HDBK-419.
> >> This is downloadable for a number of web sources.
> >> It is about 600 pages and is in two volumes.
> >> This discusses a number of different sources of EMP such as nuclear and
> >> lightning.
> >> A lot is for protection of military industrial complexes, but, there is
> >> a lot that pertains to us.
> >>
> >> I worked for a military complex that assembled nuclear missiles.
> >> The site was built to this handbook specs.
> >> We had no EMP related damage at the site.
> >>
> >> Number one rule, bond all grounds together. If something on your
> >> property takes a hit, you want everything on your property to elevate to
> >> the same level and the same rate.
> >> If you have multiple, non bonded grounds, there is a different reference
> >> for each ground. This is a major source for disaster.
> >>
> >> I spent seven years in lightning mitigation. I was told by professionals
> >> that I was wrong. The third time that their tower was struck, destroying
> >> all of the lights and attached equipment, they followed my
> >> recommendations. That was ten years ago. The three hits were within four
> >> months of each other. The site has been free of destructive hits since
> >> then.
> >>
> >> 73
> >> Glenn
> >> WB4UIV
> >>
> >>
> >>
> >>
> >
>
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> time-nuts mailing list -- time-nuts@febo.com
> To unsubscribe, go to https://www.febo.com/cgi-bin/
> mailman/listinfo/time-nuts
> and follow the instructions there.
>



-- 

Chris Albertson
Redondo Beach, California
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Re: [time-nuts] GPS antenna selection - lightning

[Clay Autery]

Is the 1987 version the latest issue available for free?

__
Clay Autery, KY5G
MONTAC Enterprises
(318) 518-1389

On 8/6/2016 8:46 AM, Glenn Little WB4UIV wrote:
> Cone of protection is addressed.
> Volume 1 is theory, volume 2 is application.
> The military requires 1/0 cable exterior to the building, commercial
> practice is #2AWG.
> Ground rod spacing is address.
>
> Overall a very good reference based on practical experience and backed
> with theory.
>
> 73
> Glenn
> WB4UIV
>
>
> On 8/6/2016 1:19 AM, Bill Hawkins wrote:
>> Hi Glenn,
>>
>> Your advice is excellent.
>>
>> Seems like every time we have a lightning discussion there is no
>> distinction between an EMP and a direct hit.
>>
>> I started work in 1960 at a blasting cap plant in upstate New York. The
>> powder magazines were protected by tall masts according to the "cone of
>> protection" theory. The angle of the cone varied between 45 and 60
>> degrees. The earth ground resistance of the mast was measured by a
>> hand-cranked device that looked like a megger but read earth resistance
>> to less than a tenth of an ohm. Had the lightning but never lost a
>> magazine.
>>
>> You say MIL-HDBK-419 covers EMP. Does it also cover cone of protection
>> for direct hits?
>>
>> I was fascinated by the idea that a simple capacitor discharge into an
>> inductor could be greatly enhanced by reducing the diameter of the
>> inductor with a conventional explosive, described in one of Stephen
>> Coonts' books, if my failing memory recalls correctly. And so I learned
>> what I could about EMP. Never built anything, just interesting behavior.
>>
>> Best regards,
>> Bill Hawkins
>>
>>
>> -----Original Message-----
>> From: time-nuts [mailto:time-nuts-boun...@febo.com] On Behalf Of Glenn
>> Little WB4UIV
>> Sent: Friday, August 05, 2016 9:47 PM
>> To: Discussion of precise time and frequency measurement
>> Subject: Re: [time-nuts]GPS antenna selection - lightning
>>
>> A very good reference for EMP protection is MIL-HDBK-419.
>> This is downloadable for a number of web sources.
>> It is about 600 pages and is in two volumes.
>> This discusses a number of different sources of EMP such as nuclear and
>> lightning.
>> A lot is for protection of military industrial complexes, but, there is
>> a lot that pertains to us.
>>
>> I worked for a military complex that assembled nuclear missiles.
>> The site was built to this handbook specs.
>> We had no EMP related damage at the site.
>>
>> Number one rule, bond all grounds together. If something on your
>> property takes a hit, you want everything on your property to elevate to
>> the same level and the same rate.
>> If you have multiple, non bonded grounds, there is a different reference
>> for each ground. This is a major source for disaster.
>>
>> I spent seven years in lightning mitigation. I was told by professionals
>> that I was wrong. The third time that their tower was struck, destroying
>> all of the lights and attached equipment, they followed my
>> recommendations. That was ten years ago. The three hits were within four
>> months of each other. The site has been free of destructive hits since
>> then.
>>
>> 73
>> Glenn
>> WB4UIV
>>
>>
>>
>>
>

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Re: [time-nuts] GPS antenna selection - lightning

[Glenn Little WB4UIV]

Cone of protection is addressed.
Volume 1 is theory, volume 2 is application.
The military requires 1/0 cable exterior to the building, commercial 
practice is #2AWG.

Ground rod spacing is address.

Overall a very good reference based on practical experience and backed 
with theory.


73
Glenn
WB4UIV


On 8/6/2016 1:19 AM, Bill Hawkins wrote:

Hi Glenn,

Your advice is excellent.

Seems like every time we have a lightning discussion there is no
distinction between an EMP and a direct hit.

I started work in 1960 at a blasting cap plant in upstate New York. The
powder magazines were protected by tall masts according to the "cone of
protection" theory. The angle of the cone varied between 45 and 60
degrees. The earth ground resistance of the mast was measured by a
hand-cranked device that looked like a megger but read earth resistance
to less than a tenth of an ohm. Had the lightning but never lost a
magazine.

You say MIL-HDBK-419 covers EMP. Does it also cover cone of protection
for direct hits?

I was fascinated by the idea that a simple capacitor discharge into an
inductor could be greatly enhanced by reducing the diameter of the
inductor with a conventional explosive, described in one of Stephen
Coonts' books, if my failing memory recalls correctly. And so I learned
what I could about EMP. Never built anything, just interesting behavior.

Best regards,
Bill Hawkins


-Original Message-
From: time-nuts [mailto:time-nuts-boun...@febo.com] On Behalf Of Glenn
Little WB4UIV
Sent: Friday, August 05, 2016 9:47 PM
To: Discussion of precise time and frequency measurement
Subject: Re: [time-nuts]GPS antenna selection - lightning

A very good reference for EMP protection is MIL-HDBK-419.
This is downloadable for a number of web sources.
It is about 600 pages and is in two volumes.
This discusses a number of different sources of EMP such as nuclear and
lightning.
A lot is for protection of military industrial complexes, but, there is
a lot that pertains to us.

I worked for a military complex that assembled nuclear missiles.
The site was built to this handbook specs.
We had no EMP related damage at the site.

Number one rule, bond all grounds together. If something on your
property takes a hit, you want everything on your property to elevate to
the same level and the same rate.
If you have multiple, non bonded grounds, there is a different reference
for each ground. This is a major source for disaster.

I spent seven years in lightning mitigation. I was told by professionals
that I was wrong. The third time that their tower was struck, destroying
all of the lights and attached equipment, they followed my
recommendations. That was ten years ago. The three hits were within four
months of each other. The site has been free of destructive hits since
then.

73
Glenn
WB4UIV






--
---
Glenn LittleARRL Technical Specialist   QCWA  LM 28417
Amateur Callsign:  WB4UIVwb4...@arrl.netAMSAT LM 2178
QTH:  Goose Creek, SC USA (EM92xx)  USSVI LM   NRA LM   SBE ARRL TAPR
"It is not the class of license that the Amateur holds but the class
of the Amateur that holds the license"
---
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Re: [time-nuts] GPS antenna selection — lightning

[Charles Steinmetz]

Glenn wrote:


A very good reference for EMP protection is MIL-HDBK-419.
This is downloadable for a number of web sources.


Tisha Hayes has a big fat folder full of good stuff relating to 
"Grounding Surge and Filtering" at her dropbox site, and another one 
full of "Transient Protection Documents."  See:




Best regards,

Charles


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[time-nuts] GPS antenna selection — lightning

[Hank Riley via time-nuts]

>From UL "Lightning Protection (2016):

"When we look at a Lightning Protection System in its most elementary form, it 
is quite simple. An air terminal(s) to attract and catch a lightning strike, a 
low resistance conducting cable that connects the air terminal to the earth 
using a conducting electrode and provide a pathway to dissipate the high energy 
into the earth. This system provides protection for the structure."
http://www.ul.com/wp-content/uploads/2014/04/LightningProtectionAG.pdf
So plain lightning rods do not operate to prevent strikes.

The notion that even various exotic spiny gizmos being marketed by a handful of 
companies, can, by dissipating charges or by other mechanisms, minimize or 
prevent lightning strikes to structures where they're installed has been 
discredited.  Or, to be conservative, the manufacturers' claims of 
lightning-prevention-by-charge dissipation devices have not been supported by 
real world tests.
There is a wealth of research in the literature on the subject of 
"unconventional methods" of lightning protection; this article from the 
Bulletin of the American Meteorological Society is a nice treatment and survey 
with many technical references.
http://www.lightningsafety.com/nlsi_lhm/Uman_Rakov.pdf
Hank




   

  
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Re: [time-nuts] GPS antenna selection — lightning

[Bob Camp]

Hi

Ummm ….. It’s a *lot* more fun to focus on the 0.001% case :)

Bob

> On Aug 5, 2016, at 9:31 PM, Chris Albertson  wrote:
> 
> You guys, well some of you are mixing to things
> 
> 1) the building code requirement to ground an antenna is for the protection
> of the building.  The building code don't care if you electronics is fried
> or not.   The wire and ground rod keep the antenna mast at earth potential.
> 
> 
> 2) Those surge protectors and grounding your electronics to a common point
> an al other advice then grounding the most to a rod by the nearest route
> down the side of the house.  These are different things
> 
> So, outdoor antenna are different from indoor antenna in that if you indoor
> antenna is struck the house is already pretty much toasted.   You still
> might want a surge protector to protect the receiver.
> 
> The question is if you need to buy a $40 surge protector for your $8
> Motorola Encore receiver?  But no question if you need a group wire in the
> mast, even for that $8 gps receiver because that wire protects the house
> 
> Part of the equation is where you live.  In many years of living in Redondo
> Beach, CA I never hear of anyone or anything being =damaged by lightening.
> We don't even get lighting here but twice a year if that.   On the other
> hand I had god protection on my sailboat as that 60 for aluminum mast might
> be the highest thing around on the ocean for miles.  That mast has a very
> solid connection straight to saltwater.  You have to evaluate the risk and
> consequence.  You get different answer in Orlando Florida then I get here.
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Re: [time-nuts] GPS antenna selection — lightning

[Glenn Little WB4UIV]

A very good reference for EMP protection is MIL-HDBK-419.
This is downloadable for a number of web sources.
It is about 600 pages and is in two volumes.
This discusses a number of different sources of EMP such as nuclear and 
lightning.
A lot is for protection of military industrial complexes, but, there is 
a lot that pertains to us.


I worked for a military complex that assembled nuclear missiles.
The site was built to this handbook specs.
We had no EMP related damage at the site.

Number one rule, bond all grounds together. If something on your 
property takes a hit, you want everything on your property to elevate to 
the same level and the same rate.
If you have multiple, non bonded grounds, there is a different reference 
for each ground. This is a major source for disaster.


I spent seven years in lightning mitigation. I was told by professionals 
that I was wrong. The third time that their tower was struck, destroying 
all of the lights and attached equipment, they followed my 
recommendations. That was ten years ago. The three hits were within four 
months of each other. The site has been free of destructive hits since then.


73
Glenn
WB4UIV



On 8/5/2016 10:37 AM, Eric Scace wrote:

Unfortunately, an antenna, cable, or piece of electronics located indoors is 
just as susceptible to lightning surges as one that is outdoors.

Lightning-induced surges couple into these systems electromagnetically across a 
wide range (VLF to SHF) of frequencies. When you think about your home from an 
electromagnetic viewpoint, just imagine your structure with all non-conductive 
materials absent. For a typical wood or brick/stone house in North America, 
what you are left with is:
metal plumbing pipes and fixtures, with their geometry suspended in space
house wiring, CATV, Ethernet, and telephone cabling, and their service drops, 
all suspended in space
electrical & electronic circuits of every kind (WiFi note, computer, 
appliances), their power supplies and AC power cords, also suspended in space
metal furniture? That’s hanging out there, suspended in space, too.
any I-beam or other steel structural elements, some random aluminum flashing, 
door knobs, and other similar metal construction materials used in the home.
That is what an electromagnetic pulse sees as it approaches and sweeps over 
your home… all hovering over a lossy ground plane (earth) its varying 
dielectric constant.. Each one of those pieces of metal, hanging in space, is 
an unintentional antenna that experiences voltage differentials and current 
flows.

A GPS antenna and its coax line that is installed next to a window is no 
different from the same antenna/coax installed one meter outside the window… or 
10 meters away outside the window. All three installations are effectively 
“outdoors” from an electromagnetic viewpoint, and all three need effective 
surge protection from lightning-, cloud-, and precipitation-induced voltage 
surges.

(N.B.: Snow can be particularly bad for voltage surges. I’ve seen thousands of 
volts per meter potential differences in moderate-to-heavy snowfall that 
produced very significant current flows on cables.)

Surge protection for your antenna, its attachment to your receiver(s), AC/DC 
power supply lines, and any other signal lines of significant length is cheap 
insurance.

My continuously-operating electronics lives in an enclosed rack cabinet — not 
too much worse than a proper Faraday cage. Every cable entering the cabinet has 
surge protection at the point of entry. The cabinet is bonded to earth ground 
by 2” copper flashing. In the past this system lived 22 years on a mountaintop 
home, 1200 ft above surrounding terrain. Lots of thunderstorms — zero 
damage/disruptions during that time… a sample size of one, admittedly, but 
during the first 18 months at that site I had two lightning-surge damaging 
events before I got serious about protection.

I have equipment at a coastal site with multiple 130-ft towers. That site had 
damage events every 2 years or so — even when cables to the “outside” were 
disconnected, and AC mains power was shut off at the main circuit breaker box. 
After implementing comprehensive surge protection, we have had zero damage over 
the last 12 years.

— Eric


On 2016 Aug 04, at 19:46 , Bob Camp  wrote:


Grounding the antenna is always a good idea.



A surge suppressor in the line could save you some
real cost if there is a lightning strike.


I did a quick search for SMA/BNC/TNC based surge
protectors and not much did come up, any suggestions
what to use there?


There are a *lot* of them on eBay. Many of them have N connectors on them.




I don’t know about Austria, but here in the US,
both are required.


Outside definitely, "inside" I'm not sure, but it
won't hurt to have additional protection for the
receiver(s).


It is a good bet that the antenna will be outside. I’d plan it that way.




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Re: [time-nuts] GPS antenna selection — lightning

[Chris Albertson]

You guys, well some of you are mixing to things

1) the building code requirement to ground an antenna is for the protection
of the building.  The building code don't care if you electronics is fried
or not.   The wire and ground rod keep the antenna mast at earth potential.


2) Those surge protectors and grounding your electronics to a common point
an al other advice then grounding the most to a rod by the nearest route
down the side of the house.  These are different things

So, outdoor antenna are different from indoor antenna in that if you indoor
antenna is struck the house is already pretty much toasted.   You still
might want a surge protector to protect the receiver.

The question is if you need to buy a $40 surge protector for your $8
Motorola Encore receiver?  But no question if you need a group wire in the
mast, even for that $8 gps receiver because that wire protects the house

Part of the equation is where you live.  In many years of living in Redondo
Beach, CA I never hear of anyone or anything being =damaged by lightening.
We don't even get lighting here but twice a year if that.   On the other
hand I had god protection on my sailboat as that 60 for aluminum mast might
be the highest thing around on the ocean for miles.  That mast has a very
solid connection straight to saltwater.  You have to evaluate the risk and
consequence.  You get different answer in Orlando Florida then I get here.
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Re: [time-nuts] GPS antenna selection

[Tom Van Baak]

Herbert Poetzl wrote:
> I'm currently investigating my options regarding 
> GPS antennae (of course for time related purposes)
> and I'm really confused by the variety they come
> in ... (my apologies in advance for the long post).

Yes, lots of variety! See: http://leapsecond.com/museum/gps-ant/

/tvb
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Re: [time-nuts] GPS antenna selection — lightning

[Alexander Pummer]

lightening protection:

http://www.ul.com/wp-content/uploads/2014/04/LightningProtectionAG.pdf

73
KJ6UHN
Alex

On 8/5/2016 1:51 PM, Attila Kinali wrote:

Hi Eric,

On Fri, 5 Aug 2016 10:37:28 -0400
Eric Scace  wrote:


A GPS antenna and its coax line that is installed next to a window is no
different from the same antenna/coax installed one meter outside the window…
or 10 meters away outside the window. All three installations are
effectively “outdoors” from an electromagnetic viewpoint, and all three need
effective surge protection from lightning-, cloud-, and precipitation-
induced voltage surges.

Please please please do NOT spread dangerous information like this!

While it is true, that an indoor antenna is suceptible to surges like
an outdoor antenna, it is not true that an outdoor antenna is equivalent
to an indoor antenna when it comes to lightning protection.

Because an outdoor antenna can be _directly_ hit by a lightning.

To protect the house and its inhabitants from the lightning strike,
an external antenna needs to be either lower than any lightning rod
and within its 45m ball or needs its own conductor and grounding
to discharge any lightning energy and thus preventing it from following
the antenna cable into the house.

Please be aware that the grounding of the antenna is not to protect
the equipment from surges, but to prevent conduction of the lightning
into the house that could cause electrocution and fires.

Attila Kinali



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