Re: [time-nuts] LightSquared vs old GPS gear: Antennas?

[George Dubovsky]

I have recently done some side-by-side testing of a new PCTel antenna vs an
older Trimble bullet antenna to see if there was any degradation of GPS
operation. The PCTel had 26 dB gain and a sharp bandpass filter incorporated
that was 60 dB down at the the lower edge of the GPS band (upper edge of
lightsquared), but the Trimble bandpass rolled off more gradually. Both
operated fine in GPS service, but the PCTel would be more likely to survive
LS QRM in timing apps. Unfortunately, the price is the same as just about
any new GPS basestation antenna, which places it at the upper end of the
budget for all but the dedicated hobbiest.

73,

geo - n4ua

On Fri, Jun 10, 2011 at 9:15 PM, Hal Murray  wrote:

>
> Is it possible/interesting to design an antenna that has a low-angle cutoff
> at 20 or 30 degrees?  That probably won't eliminate many satellites that
> are
> useful for timing receivers.
>
> I'm interested in things like a Z3801A or a ThunderBolt.  I'm assuming it
> is
> not reasonable to replace the GPS unit.  Replacing the antenna might be
> reasonable, assuming it's cost is low enough.
>
> That only helps in a donut shape area around the LightSquared antennas.
> Farther away it's not necessary.  Too close and either the antenna would be
> too high or the power would burn through the antenna anyway.
>
> I live in flat ground.  I'm not sure where the nearest cell phone tower is.
> I don't know of any on the nearby hills to the west.  To the east, they are
> either low or far away.  (Maybe I just haven't noticed them yet.)
>
> Another option would be a setup to null out an signal at a specific compass
> angle.
>
> I realize this won't help the zillions of currently installed GPS
> navigation
> units.  They are mostly consumer gear with relatively short expected
> lifetimes so the FCC might do something like say "5 years from now..."
> which
> would be nasty for people like us using ancient gear.
>
>
>
> --
> These are my opinions, not necessarily my employer's.  I hate spam.
>
>
>
>
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[time-nuts] HP Z3801A, GPS vs UTC?

[Ron Hahn (EI2JP)]

On 6/7/2011 10:40 PM, cook michael wrote:
> Le 07/06/2011 21:15, r...@lcs.mit.edu a écrit :
>> I have an HP 58503A. It has an "Option H14,H19" sticker on the back. The
>> circuit board has "58503-60001 Rev C" stamped on it. It has been running
>> continuously and locked to GPS for a few days, and it knows the correct
>> number of seconds between GPS and UTC.
>>
>> The unit displays GPS time, without the leap seconds correction. The
>> front-panel display says "GPS xx:yy:zz", and ":system:status?" says "GPS
>> 1PPS Synchronized to GPS Time", not "to UTC" as the manual shows.
>>
>> I'd be much obliged if anyone could tell me how to get the unit
>> to display UTC instead of GPS time.
> I think these use a similar command set to the Z3801A
> try
> :diag:gps:utc?should show 0 if the unit is in GPS,
> 1 if UTC
> if that gives coherent results, try
> :diag:gps:utc 1
> to force the mode
Colleagues,

For someone who is not understanding these modes, can you explain what
is this difference between UTC and GPS time?  I have a HP Z3801A which I
have been using for some years.  Do I need to change this to UTC time?

Thanks,

Ron

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Re: [time-nuts] HP Z3801A, GPS vs UTC?

[jmfranke]

GPS time differs from UTC by the number of leap seconds accumulated since 
the start of GPS time. Reseting the GPS clocks each time a leap second 
occurs would upset the code generators. The satellites stay in GPS time but 
do transmit the difference between UTC and GPS time to allow receivers to 
make the conversion. If your time display is in sync with the seconds time 
signal from WWV or CHU, your system is set to display UTC. GPS time is 
currently ahead of UTC by 15 seconds. Each time a leap second is added, UTC 
falls one more second behind GPS time. If a leap second is subtracted, UTC 
will move closer to GPS time.

See: http://leapsecond.com/java/gpsclock.htm

John  WA4WDL

--
From: "Ron Hahn (EI2JP)" 
Sent: Saturday, June 11, 2011 8:11 AM
To: 
Subject: [time-nuts] HP Z3801A, GPS vs UTC?


On 6/7/2011 10:40 PM, cook michael wrote:

Le 07/06/2011 21:15, r...@lcs.mit.edu a écrit :

I have an HP 58503A. It has an "Option H14,H19" sticker on the back. The
circuit board has "58503-60001 Rev C" stamped on it. It has been running
continuously and locked to GPS for a few days, and it knows the correct
number of seconds between GPS and UTC.

The unit displays GPS time, without the leap seconds correction. The
front-panel display says "GPS xx:yy:zz", and ":system:status?" says "GPS
1PPS Synchronized to GPS Time", not "to UTC" as the manual shows.

I'd be much obliged if anyone could tell me how to get the unit
to display UTC instead of GPS time.

I think these use a similar command set to the Z3801A
try
:diag:gps:utc?should show 0 if the unit is in GPS,
1 if UTC
if that gives coherent results, try
:diag:gps:utc 1
to force the mode

Colleagues,

For someone who is not understanding these modes, can you explain what
is this difference between UTC and GPS time?  I have a HP Z3801A which I
have been using for some years.  Do I need to change this to UTC time?

Thanks,

Ron

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Re: [time-nuts] HP Z3801A, GPS vs UTC?

[Magnus Danielson]

On 06/11/2011 02:11 PM, Ron Hahn (EI2JP) wrote:

On 6/7/2011 10:40 PM, cook michael wrote:

Le 07/06/2011 21:15, r...@lcs.mit.edu a écrit :

I have an HP 58503A. It has an "Option H14,H19" sticker on the back. The
circuit board has "58503-60001 Rev C" stamped on it. It has been running
continuously and locked to GPS for a few days, and it knows the correct
number of seconds between GPS and UTC.

The unit displays GPS time, without the leap seconds correction. The
front-panel display says "GPS xx:yy:zz", and ":system:status?" says "GPS
1PPS Synchronized to GPS Time", not "to UTC" as the manual shows.

I'd be much obliged if anyone could tell me how to get the unit
to display UTC instead of GPS time.

I think these use a similar command set to the Z3801A
try
:diag:gps:utc?should show 0 if the unit is in GPS,
1 if UTC
if that gives coherent results, try
:diag:gps:utc 1
to force the mode

Colleagues,

For someone who is not understanding these modes, can you explain what
is this difference between UTC and GPS time?  I have a HP Z3801A which I
have been using for some years.  Do I need to change this to UTC time?


If you only wish a 10 MHz and PPS, no. GPS time will do just as well.
If you also want UTC time for NTP server for instance, then you do want 
either to use the UTC mode or let the server know it runs on GPS time 
and compensate itself.


Cheers,
Magnus

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Re: [time-nuts] GPS interference and history...

[Bob Camp]

Hi

Best guess - a few million timing receivers are out there. Probably not over 
ten million. To replace them at "new" prices, figure $5000 each including 
the labor. Lots of variables, might be twenty billion dollars if you did a 
straight swap.
Changing out antennas would be cheaper for the hardware and likely more for 
the labor if a tower is involved. Might be half the price of doing the 
receivers.


Quick math:

Take a tower count (say 250,000). Assume each system on the tower has doubly 
redundant GPS.  Take a reasonable number of systems per tower (at least 1 
likely >4). That gets you to a million pretty quick. Add to that the 
non-cell tower telcom stuff and you likely double or triple the number.


Bob

-Original Message- 
From: Hal Murray

Sent: Friday, June 10, 2011 10:01 PM
To: Discussion of precise time and frequency measurement
Subject: Re: [time-nuts] GPS interference and history...


li...@rtty.us said:

There's an enormous amount of gear out there that gets timing off of GPS.


That's an interesting claim.  Does anybody have any data on the usage of GPS
for timing?

I assume there is one in every cell tower and one in every 911 call center.
Are there other large categories of users?

What would it cost to replace all of it?  If you wanted to do something like
that, what would "it" cover?  How about people like us running old recycled
gear?  (Z3801A, ThunderBolt, ...)


I think I saw one last week.  It was on a river level measuring station on
the Sacramento River.  It was a small block building.  There was an antenna
pointing up into the sky.  I assume there is a satellite up there.  There 
was

also a small (~3 inch dia) hemisphere antenna. I assume it was GPS.  (They
had power going into the building (no solar panels) so it should have been
simple to get a phone line too.)

I'm not sure why they need GPS at the recording house.  They know where it 
is

so timing is the only use I can think of.  But they could also get that at
the receiving end.  Millisecond accuracy isn't helpful.  Second level
accuracy might be interesting if something breaks and you want to know when
the wave got to downstream stations.  The risetime is probably over a 
second.



--
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Re: [time-nuts] GPS interference and history...

[Jim Lux]

On 6/10/11 7:01 PM, Hal Murray wrote:


li...@rtty.us said:

There's an enormous amount of gear out there that gets timing off of GPS.


That's an interesting claim.  Does anybody have any data on the usage of GPS
for timing?

I assume there is one in every cell tower and one in every 911 call center.
Are there other large categories of users?


GPS timing antennas are sprouting like mushrooms in a lawn all over JPL. 
 (that's what they look like... you'll be walking around, and you'll 
notice that there's 2 or 3 new stalks sticking up with a little antenna 
on the top, and conduit running down the side of the building)


While we have masers and cesium sources at JPL, they're not distributed 
everywhere.  So, usually, the "easy" solution is to just get yourself a 
Symmetricom or Fluke box, have facilities install the antenna, and your 
lab is set.





I think I saw one last week.  It was on a river level measuring station on
the Sacramento River.  It was a small block building.  There was an antenna
pointing up into the sky.  I assume there is a satellite up there.  There was
also a small (~3 inch dia) hemisphere antenna. I assume it was GPS.  (They
had power going into the building (no solar panels) so it should have been
simple to get a phone line too.)

I'm not sure why they need GPS at the recording house.  They know where it is
so timing is the only use I can think of.  But they could also get that at
the receiving end.  Millisecond accuracy isn't helpful.  Second level
accuracy might be interesting if something breaks and you want to know when
the wave got to downstream stations.  The risetime is probably over a second.



GPS is easy, that's why. It's under YOUR control. You spend a few 
thousand bucks (including installation labor) and you have something 
that works now and for the foreseeable future that you don't have to 
worry about a comm line dropping, or resetting a clock or any of a 
multitude of things.


Think about it.. what other totally off the shelf approach is there to 
get time to 1 second accuracy over a span of years and temperatures that 
does not require periodic "setting the clock"









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Re: [time-nuts] HP Z3801A, GPS vs UTC?, NTP

[Ron Hahn (EI2JP)]

On 6/11/2011 2:47 PM, Magnus Danielson wrote:
> On 06/11/2011 02:11 PM, Ron Hahn (EI2JP) wrote:
>> On 6/7/2011 10:40 PM, cook michael wrote:
>>> Le 07/06/2011 21:15, r...@lcs.mit.edu a écrit :
 I have an HP 58503A. It has an "Option H14,H19" sticker on the
 back. The
 circuit board has "58503-60001 Rev C" stamped on it. It has been
 running
 continuously and locked to GPS for a few days, and it knows the
 correct
 number of seconds between GPS and UTC.

 The unit displays GPS time, without the leap seconds correction. The
 front-panel display says "GPS xx:yy:zz", and ":system:status?" says
 "GPS
 1PPS Synchronized to GPS Time", not "to UTC" as the manual shows.

 I'd be much obliged if anyone could tell me how to get the unit
 to display UTC instead of GPS time.
>>> I think these use a similar command set to the Z3801A
>>> try
>>> :diag:gps:utc?should show 0 if the unit is in GPS,
>>> 1 if UTC
>>> if that gives coherent results, try
>>> :diag:gps:utc 1
>>> to force the mode
>> Colleagues,
>>
>> For someone who is not understanding these modes, can you explain what
>> is this difference between UTC and GPS time?  I have a HP Z3801A which I
>> have been using for some years.  Do I need to change this to UTC time?
>
> If you only wish a 10 MHz and PPS, no. GPS time will do just as well.
> If you also want UTC time for NTP server for instance, then you do
> want either to use the UTC mode or let the server know it runs on GPS
> time and compensate itself.
>
Magnus,

I am interested in UTC time for weather satellite reception,
synchronising via NTP.  I tried the GPSCON program for the Z3801A but
could never get it to broadcast ntp information on my LAN.  Recently, I
have purchased some Sure GPS boards from Sure Electronics
(http://www.sureelectronics.net/goods.php?id=99).  David Taylor has a
great page on this at http://satsignal.eu/ntp/Sure-GPS.htm ... but now I
am thinking his time is maybe always 15 seconds off, yes??

R

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Re: [time-nuts] HP Z3801A, GPS vs UTC?, NTP

[Magnus Danielson]

Ron,


Magnus,

I am interested in UTC time for weather satellite reception,
synchronising via NTP.  I tried the GPSCON program for the Z3801A but
could never get it to broadcast ntp information on my LAN.  Recently, I
have purchased some Sure GPS boards from Sure Electronics
(http://www.sureelectronics.net/goods.php?id=99).  David Taylor has a
great page on this at http://satsignal.eu/ntp/Sure-GPS.htm ... but now I
am thinking his time is maybe always 15 seconds off, yes??


No, as far as I recall it the Sure GPS board always default to UTC time. 
Neat little board.


You should be able to use the NTP from ntp.org (or whatever source you 
like) to achieve it with either the Z3801A or the Sure GPS. Need to set 
something like that up again, been ages since I tried it last.


Since 15 seconds is easy to observe you can always use NTP to any of the 
public servers (NTP pool, any fellow time-nut) just to get UTC time to a 
computer and just comparing reading will suffice... :)


Cheers,
Magnus

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Re: [time-nuts] GPS interference and history...

[WA1ZMS]

bob-

you coming to greylock?


-Brian, WA1ZMS

On Jun 11, 2011, at 12:13 AM, bownes  wrote:



That small hemispherical antenna could also have been 900mhz. I have  
one here @ home that is a combined gps/900mhz antenna from an  
ambulance tracking system.



On Jun 10, 2011, at 22:01, Hal Murray  wrote:



li...@rtty.us said:
There's an enormous amount of gear out there that gets timing off  
of GPS.


That's an interesting claim.  Does anybody have any data on the  
usage of GPS

for timing?

I assume there is one in every cell tower and one in every 911 call  
center.

Are there other large categories of users?

What would it cost to replace all of it?  If you wanted to do  
something like
that, what would "it" cover?  How about people like us running old  
recycled

gear?  (Z3801A, ThunderBolt, ...)


I think I saw one last week.  It was on a river level measuring  
station on
the Sacramento River.  It was a small block building.  There was an  
antenna
pointing up into the sky.  I assume there is a satellite up there.   
There was
also a small (~3 inch dia) hemisphere antenna. I assume it was  
GPS.  (They
had power going into the building (no solar panels) so it should  
have been

simple to get a phone line too.)

I'm not sure why they need GPS at the recording house.  They know  
where it is
so timing is the only use I can think of.  But they could also get  
that at

the receiving end.  Millisecond accuracy isn't helpful.  Second level
accuracy might be interesting if something breaks and you want to  
know when
the wave got to downstream stations.  The risetime is probably over  
a second.



--
These are my opinions, not necessarily my employer's.  I hate spam.




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Re: [time-nuts] HP Z3801A, GPS vs UTC?, NTP

[David J Taylor]

Magnus,

I am interested in UTC time for weather satellite reception,
synchronising via NTP.  I tried the GPSCON program for the Z3801A but
could never get it to broadcast ntp information on my LAN.  Recently, I
have purchased some Sure GPS boards from Sure Electronics
(http://www.sureelectronics.net/goods.php?id=99).  David Taylor has a
great page on this at http://satsignal.eu/ntp/Sure-GPS.htm ... but now I
am thinking his time is maybe always 15 seconds off, yes??

R


Ron,

No, the time is UTC and not GPS, so it's "correct" and not 15s out.  To be 
sure (and as is good practice in any case), do include an Internet server 
or two in your ntp.conf file.  Something like this:


# ref-clock drivers - Sure Electronics GPS board
server  127.127.22.1minpoll 4
server  127.127.20.1minpoll 4  mode 18  prefer

# Use specific NTP servers
server  0.uk.pool.ntp.org   minpoll 10
server  1.uk.pool.ntp.org   minpoll 10
server  0.nl.pool.ntp.org   minpoll 10
server  1.nl.pool.ntp.org   minpoll 10

You can use "ntpq -p" to check the offset of the Sure board relative to 
the Internet servers.


Thanks for letting me know that the Web pages were helpful.

73,
David
--
SatSignal software - quality software written to your requirements
Web:  http://www.satsignal.eu
Email:  david-tay...@blueyonder.co.uk 



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Re: [time-nuts] locate 6 digit digital clock

[Jason Rabel]

Since people are showing off their clocks... I managed to get a Datum / Bancomm 
bc632D display from eBay a while back and it's
pretty cool.

>From what I can tell, they took an off-the-shelf model from Beta Brite (Now I 
>think owned by Adaptive) and put an extra board in
there with the BNC connections, and of course their own firmware. From what I 
can tell most of those signs are just meant for
scrolling text and don't have any time ability.

http://www.rabel.org/archives/Images/bc632D/

The bc632D can decode several different time formats (I have it hooked up to 
IRIG), it has a RTC so it can flywheel when no input or
if you manually input the date/time. The only quirk is it doesn't decode the 
year properly, but once you set it manually it will
maintain the correct year (unless you leave it unplugged for a long time and 
the onboard battery runs out). You have a variety of
display options, but it's not as customizable as one would hope. I have it 
showing the time, then every 30 it will show the date for
5 seconds. Text size is about 2-1/4" high.

I think I paid around $50 for the sign on eBay, but had to pay about another 
$40 for a proper power supply (required 7 VAC.. not
DC). Still for under $100 I think it's a deal.


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Re: [time-nuts] HP Z3801A, GPS vs UTC?

[J. L. Trantham]

I have been wondering about this.

Since leap seconds accumulate from time to time, there must be a
'difference' between GPS and UTC.  Is the difference related to the rotation
of the earth around it's axis and around the sun and thus the need to add a
second or so from time to time as we do with leap year or is there a
difference in the reference oscillator frequency between the two that allows
a 'drift' of a second or so from time to time?  I suspect the former.

Joe



-Original Message-
From: time-nuts-boun...@febo.com [mailto:time-nuts-boun...@febo.com] On
Behalf Of Magnus Danielson
Sent: Saturday, June 11, 2011 8:47 AM
To: time-nuts@febo.com
Subject: Re: [time-nuts] HP Z3801A, GPS vs UTC?


On 06/11/2011 02:11 PM, Ron Hahn (EI2JP) wrote:
> On 6/7/2011 10:40 PM, cook michael wrote:
>> Le 07/06/2011 21:15, r...@lcs.mit.edu a écrit :
>>> I have an HP 58503A. It has an "Option H14,H19" sticker on the back. 
>>> The circuit board has "58503-60001 Rev C" stamped on it. It has been 
>>> running continuously and locked to GPS for a few days, and it knows 
>>> the correct number of seconds between GPS and UTC.
>>>
>>> The unit displays GPS time, without the leap seconds correction. The 
>>> front-panel display says "GPS xx:yy:zz", and ":system:status?" says 
>>> "GPS 1PPS Synchronized to GPS Time", not "to UTC" as the manual 
>>> shows.
>>>
>>> I'd be much obliged if anyone could tell me how to get the unit to 
>>> display UTC instead of GPS time.
>> I think these use a similar command set to the Z3801A
>> try
>> :diag:gps:utc?should show 0 if the unit is in GPS,
>> 1 if UTC
>> if that gives coherent results, try
>> :diag:gps:utc 1
>> to force the mode
> Colleagues,
>
> For someone who is not understanding these modes, can you explain what 
> is this difference between UTC and GPS time?  I have a HP Z3801A which 
> I have been using for some years.  Do I need to change this to UTC 
> time?

If you only wish a 10 MHz and PPS, no. GPS time will do just as well. If you
also want UTC time for NTP server for instance, then you do want 
either to use the UTC mode or let the server know it runs on GPS time 
and compensate itself.

Cheers,
Magnus

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Re: [time-nuts] HP Z3801A, GPS vs UTC?

[jmfranke]

The former.

John  WA4WDL

--
From: "J. L. Trantham" 
Sent: Saturday, June 11, 2011 4:16 PM
To: "'Discussion of precise time and frequency measurement'" 


Subject: Re: [time-nuts] HP Z3801A, GPS vs UTC?


I have been wondering about this.

Since leap seconds accumulate from time to time, there must be a
'difference' between GPS and UTC.  Is the difference related to the 
rotation
of the earth around it's axis and around the sun and thus the need to add 
a

second or so from time to time as we do with leap year or is there a
difference in the reference oscillator frequency between the two that 
allows

a 'drift' of a second or so from time to time?  I suspect the former.

Joe



-Original Message-
From: time-nuts-boun...@febo.com [mailto:time-nuts-boun...@febo.com] On
Behalf Of Magnus Danielson
Sent: Saturday, June 11, 2011 8:47 AM
To: time-nuts@febo.com
Subject: Re: [time-nuts] HP Z3801A, GPS vs UTC?


On 06/11/2011 02:11 PM, Ron Hahn (EI2JP) wrote:

On 6/7/2011 10:40 PM, cook michael wrote:

Le 07/06/2011 21:15, r...@lcs.mit.edu a écrit :

I have an HP 58503A. It has an "Option H14,H19" sticker on the back.
The circuit board has "58503-60001 Rev C" stamped on it. It has been
running continuously and locked to GPS for a few days, and it knows
the correct number of seconds between GPS and UTC.

The unit displays GPS time, without the leap seconds correction. The
front-panel display says "GPS xx:yy:zz", and ":system:status?" says
"GPS 1PPS Synchronized to GPS Time", not "to UTC" as the manual
shows.

I'd be much obliged if anyone could tell me how to get the unit to
display UTC instead of GPS time.

I think these use a similar command set to the Z3801A
try
:diag:gps:utc?should show 0 if the unit is in GPS,
1 if UTC
if that gives coherent results, try
:diag:gps:utc 1
to force the mode

Colleagues,

For someone who is not understanding these modes, can you explain what
is this difference between UTC and GPS time?  I have a HP Z3801A which
I have been using for some years.  Do I need to change this to UTC
time?


If you only wish a 10 MHz and PPS, no. GPS time will do just as well. If 
you

also want UTC time for NTP server for instance, then you do want
either to use the UTC mode or let the server know it runs on GPS time
and compensate itself.

Cheers,
Magnus

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Re: [time-nuts] locate 6 digit digital clock

[Ken , VK7KRJ]

It's not up to time-nuts standard, but here is my gps clock I built some years ago. It 
uses a Motorola Oncore board for the gps and I didn't bother with trying to compensate for 
the delay my software causes. I did put in a routine to allow for daylight saving (curious 
concept- a bit like cutting your head off and standing on it to make yourself taller!) but 
the politicians keep messing with the dates, so it is an hour out for a while twice a year.

Next (electronics) project is the same thing, but with my newly acquired 
thunderbolt.

On 2011-06-12 03:25, Jason Rabel wrote:

Since people are showing off their clocks... I managed to get a Datum / Bancomm 
bc632D display from eBay a while back and it's
pretty cool.


--
Cheers, Ken
vk7...@users.tasmanet.com.au
www.vk7krj.com

'It seems hard to sneak a look at God's cards. But that He plays dice and uses
"telepathic" methods  is something that I cannot believe for a single
moment.' (Einstein's famous quote on Quantum theory)
No virus found in this outgoing message.
Checked by AVG - www.avg.com
Version: 9.0.901 / Virus Database: 271.1.1/3695 - Release Date: 06/11/11 
19:06:00
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Re: [time-nuts] locate 6 digit digital clock

[Ken , VK7KRJ]

Aarghh- it's too early in the morning for thinking- here is the url!!

http://www.vk7krj.com/ham_stuff.html

On 2011-06-12 06:55, Ken , VK7KRJ wrote:

It's not up to time-nuts standard, but here is my gps clock I built some years 
ago. It
uses a Motorola Oncore board for the gps and I didn't bother with trying to 
compensate for
the delay my software causes. I did put in a routine to allow for daylight 
saving (curious
concept- a bit like cutting your head off and standing on it to make yourself 
taller!) but
the politicians keep messing with the dates, so it is an hour out for a while 
twice a year.
Next (electronics) project is the same thing, but with my newly acquired 
thunderbolt.

On 2011-06-12 03:25, Jason Rabel wrote:

Since people are showing off their clocks... I managed to get a Datum / Bancomm 
bc632D
display from eBay a while back and it's
pretty cool.


--
Cheers, Ken
vk7...@users.tasmanet.com.au
www.vk7krj.com

'It seems hard to sneak a look at God's cards. But that He plays dice and uses
"telepathic" methods  is something that I cannot believe for a single
moment.' (Einstein's famous quote on Quantum theory)
No virus found in this outgoing message.
Checked by AVG - www.avg.com
Version: 9.0.901 / Virus Database: 271.1.1/3695 - Release Date: 06/11/11 
19:06:00
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Re: [time-nuts] locate 6 digit digital clock

[Neville Michie]

TRY http://www.vk7krj.com/ham_stuff.htm

Neville



On 12/06/2011, at 6:58 AM, Ken , VK7KRJ wrote:


Aarghh- it's too early in the morning for thinking- here is the url!!

http://www.vk7krj.com/ham_stuff.html

On 2011-06-12 06:55, Ken , VK7KRJ wrote:
It's not up to time-nuts standard, but here is my gps clock I  
built some years ago. It
uses a Motorola Oncore board for the gps and I didn't bother with  
trying to compensate for
the delay my software causes. I did put in a routine to allow for  
daylight saving (curious
concept- a bit like cutting your head off and standing on it to  
make yourself taller!) but
the politicians keep messing with the dates, so it is an hour out  
for a while twice a year.
Next (electronics) project is the same thing, but with my newly  
acquired thunderbolt.


On 2011-06-12 03:25, Jason Rabel wrote:
Since people are showing off their clocks... I managed to get a  
Datum / Bancomm bc632D

display from eBay a while back and it's
pretty cool.


--
Cheers, Ken
vk7...@users.tasmanet.com.au
www.vk7krj.com

'It seems hard to sneak a look at God's cards. But that He plays  
dice and uses
"telepathic" methods  is something that I cannot believe for a  
single

moment.' (Einstein's famous quote on Quantum theory)
No virus found in this outgoing message.
Checked by AVG - www.avg.com
Version: 9.0.901 / Virus Database: 271.1.1/3695 - Release Date:  
06/11/11 19:06:00

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time-nuts

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[time-nuts] Thunderbolt no usable sats.

[Thomas S. Knutsen]

I bougth an Thunderbolt off E-bay some time ago, to use as reference
for my spectrum analyzer and signal generators.
I had it connected up with a couple of power supplies and it worked as
it should.
Today I put together an voltage inverter to get the -12V to the GPS in
order to use it with an single 12V power supply.

When re-starting the GPS, it did an servey but did not find any usable
satelites, I did think that it just needed some time, and left it on
for a couple of hours. It still show no usable sats.

When monitoring the GPS with Lady Heather the clock show an time, but
it states no usable sats and none are visible in the map.
The GPS antenna is in the attic and have approx 25dB gain (with cable loss).

Is there any known issues with this? I did look through the archives
but found nothing.

Is the -12V used for more than the RS-232? if not, would it be
possible to replace it with an other type that don't ned -12V?

BR
Thomas.

-- 

 Please  avoid sending  me  Word  or  PowerPoint  attachments.
 See  

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Re: [time-nuts] Thunderbolt no usable sats.

[WB6BNQ]

Hello Thomas,

The first question is did you measure the minus 12 output of your inverter to
make sure it was not being loaded down too far when powering the Thunderbolt ?

If it was working on the original minus 12 volt supply properly, then it would
seem that there is a problem with your inverter.  I would consider hooking up 
the
original negative supply and measuring the current consumption to see if it is
too high for the inverter circuit.

BillWB6BNQ


"Thomas S. Knutsen" wrote:

> I bougth an Thunderbolt off E-bay some time ago, to use as reference
> for my spectrum analyzer and signal generators.
> I had it connected up with a couple of power supplies and it worked as
> it should.
> Today I put together an voltage inverter to get the -12V to the GPS in
> order to use it with an single 12V power supply.
>
> When re-starting the GPS, it did an servey but did not find any usable
> satelites, I did think that it just needed some time, and left it on
> for a couple of hours. It still show no usable sats.
>
> When monitoring the GPS with Lady Heather the clock show an time, but
> it states no usable sats and none are visible in the map.
> The GPS antenna is in the attic and have approx 25dB gain (with cable loss).
>
> Is there any known issues with this? I did look through the archives
> but found nothing.
>
> Is the -12V used for more than the RS-232? if not, would it be
> possible to replace it with an other type that don't ned -12V?
>
> BR
> Thomas.
>
> --
>
>  Please  avoid sending  me  Word  or  PowerPoint  attachments.
>  See  
>
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Re: [time-nuts] GPS interference and history...

[James C Cotton]

Any enterprise large enough to have an IT deparment needs 
precise timing.  The cheapest stratum one source is GPS.

I work at a Research II university and have several in our network.

The time is the public key for our routers that send encrypted 
routing table updates to each other.

There are several "mushrooms" over the EE wing of the College of 
Engineering, and at least one over the ME neighborhood for some 
laser measurement equipment...

One EE lab that is doing some GPS signal analysis has at least one
16 way splitter...

Jim Cotton
n8qoh

- Original Message -
> From: "Jim Lux" 
> To: time-nuts@febo.com
> Sent: Saturday, June 11, 2011 10:08:18 AM
> Subject: Re: [time-nuts] GPS interference and history...
> On 6/10/11 7:01 PM, Hal Murray wrote:
> >
> > li...@rtty.us said:
> >> There's an enormous amount of gear out there that gets timing off
> >> of GPS.
> >
> > That's an interesting claim. Does anybody have any data on the usage
> > of GPS
> > for timing?
> >
> > I assume there is one in every cell tower and one in every 911 call
> > center.
> > Are there other large categories of users?
> 
> GPS timing antennas are sprouting like mushrooms in a lawn all over
> JPL.
> (that's what they look like... you'll be walking around, and you'll
> notice that there's 2 or 3 new stalks sticking up with a little
> antenna
> on the top, and conduit running down the side of the building)
> 
> While we have masers and cesium sources at JPL, they're not
> distributed
> everywhere. So, usually, the "easy" solution is to just get yourself a
> Symmetricom or Fluke box, have facilities install the antenna, and
> your
> lab is set.
> 
> 
> >
> > I think I saw one last week. It was on a river level measuring
> > station on
> > the Sacramento River. It was a small block building. There was an
> > antenna
> > pointing up into the sky. I assume there is a satellite up there.
> > There was
> > also a small (~3 inch dia) hemisphere antenna. I assume it was GPS.
> > (They
> > had power going into the building (no solar panels) so it should
> > have been
> > simple to get a phone line too.)
> >
> > I'm not sure why they need GPS at the recording house. They know
> > where it is
> > so timing is the only use I can think of. But they could also get
> > that at
> > the receiving end. Millisecond accuracy isn't helpful. Second level
> > accuracy might be interesting if something breaks and you want to
> > know when
> > the wave got to downstream stations. The risetime is probably over a
> > second.
> 
> 
> GPS is easy, that's why. It's under YOUR control. You spend a few
> thousand bucks (including installation labor) and you have something
> that works now and for the foreseeable future that you don't have to
> worry about a comm line dropping, or resetting a clock or any of a
> multitude of things.
> 
> Think about it.. what other totally off the shelf approach is there to
> get time to 1 second accuracy over a span of years and temperatures
> that
> does not require periodic "setting the clock"
> 
> 
> >
> >
> 
> 
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Re: [time-nuts] GPS interference and history...

[Chuck Forsberg WA7KGX N2469R]

I remember a professor at the University of Wisconsin Madison
who postulated the advancement of Man could be measured by
man's advancing technology of measuring time.  We have come
a long way to get down to nanoseconds, LigutSquared notwithstanding.

I suppose the next advance will be to some soft of star date system.

--
Chuck Forsberg WA7KGX N2469R c...@omen.com   www.omen.com
Developer of Industrial ZMODEM(Tm) for Embedded Applications
  Omen Technology Inc  "The High Reliability Software"
10255 NW Old Cornelius Pass Portland OR 97231   503-614-0430


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