Re: [time-nuts] Charles Wenzel GPSDO

[Don Lewis]

I couldn't agree more!

I have converted loads of equipment to the so-called 'standard' Power Pole.

What a disappointment.  IMO, they are poorly designed and ineffective. 
Sure, they offer commonality, but at what cost?


The DO come apart easily, and if the radio (equipment) happens to be on, 
voltage spikes (pulses) can be induced, causing intermittent operation 
(resetting memories) or death to the unit.


Like Lemmings over a cliff...  they are used.

I really do not like these connectors.

Don
N5CID





-Original Message- 
From: Wes

Sent: Wednesday, June 21, 2017 8:50 PM
To: time-nuts@febo.com
Subject: Re: [time-nuts] Charles Wenzel GPSDO

Although I've reluctantly bought into the amateur radio "standardization" 
hype

of Power Poles and have a distribution panel with a plethora of them, I
basically dislike them.  The ones on my Elecraft K3 and K3S pull out 
frequently

when I move the radios and installing them is a PITA.

I never had such problems with radios with Molex connectors.

Wes Stewart


On 6/21/2017 2:36 PM, Brooke Clarke wrote:

Hi Chuck:

I'd replace the push on DC power connector with a high force Power Pole. 
I can't count how many times one of these push on connectors has worked 
itself loose.

http://www.prc68.com/I/PowerPole.shtml



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[time-nuts] TruePosition on the Arduino

[randy nordlund]

The address on my display is 0x3F.

I have a kit that was put together by the Packrats and the display works with 
their code.


Randy

VE3AX



On Tue, Jun 20, 2017 at 6:02 PM, Tom Miller https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts>> wrote:
> Has anyone been able to get the Packrat software to work with a display? I
> have been successful getting the Arduino board to initialize the
> Trueposition board but can't get the display right.
>
> The problem seems to be getting the I2C addressing correct. There are
> several 16x2 line displays available but they address at 0x20 to 0x27 and
> 0x38 to 0x3F. Neither of these work.
>
> Since we do not have the source, is there any way to find out what address
> is in use?
>
> Regards
>
> - Original Message - From: "Gregory Beat"  icloud.com>
> To:  febo.com>
> Sent: Tuesday, June 06, 2017 8:44 PM
> Subject: Re: [time-nuts] TruePosition on the Arduino
>
>
>> Ben -
>> I assume that you never received the Arduino "C code"
>> written by Bruce, WA3YUE for the original project?
>>
>> Club's Powerpoint presentation indicated that source code was available.
>> http://www.packratvhf.com/techinal.htm
>>
>> Packrat GPS Project (Gary, WA2OMY; Bruce, WA3YUE; George, KA3WXV) with
>> TruePosition GPSDO and Arduino
>> by The Mt. Airy VHF Radio Club "Pack Rats" (Southampton, PA).
>> http://www.qsl.net/wa2omy/A%20Packrat%20GPS%20Receiver%20Project.pdf
>>
>> greg, w9gb
>> ==
>>>
>>> original message / digest <
>>
>> I'm getting to the point that once I've got the button logic working, I'll
>> send out my source to anyone who wants to take a look at it or use it.
>> I will stipulate one condition - you can't make too much fun of how poorly
>> programmed it is.  ;)
>> thanks much and 73,
>> ben, kd5byb
>> ==
>> Sent from iPad Air
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>> febo.com
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--

Chris Albertson
Redondo Beach, California

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Re: [time-nuts] Charles Wenzel GPSDO

[Wes]

Although I've reluctantly bought into the amateur radio "standardization" hype 
of Power Poles and have a distribution panel with a plethora of them, I 
basically dislike them.  The ones on my Elecraft K3 and K3S pull out frequently 
when I move the radios and installing them is a PITA.


I never had such problems with radios with Molex connectors.

Wes Stewart


On 6/21/2017 2:36 PM, Brooke Clarke wrote:

Hi Chuck:

I'd replace the push on DC power connector with a high force Power Pole.  I 
can't count how many times one of these push on connectors has worked itself 
loose.

http://www.prc68.com/I/PowerPole.shtml



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Re: [time-nuts] KS24019 units PSU requirements

[Rodger Adams via time-nuts]

I have the same pair.  At 24 volts, they draw a total of about 2 amps at 
turn-on (both units, total).  After they’ve warmed up it drops to a steady 1.1 
amps.

I bought a Meanwell LRS-100-24 which is capable of 4.5 amps.  Very small, runs 
cool and cost about $25.

Rodger



> On Jun 21, 2017, at 9:44 AM, David C. Partridge 
>  wrote:
> 
> I have a pair of L108 (RFTGm-II-Rb) and L109 (RFTGM-II-XO). 
> 
> What current do these bad boys draw so I don't get too skinny a 24V PSU?
> 
> Thanks
> Dave
> 
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Re: [time-nuts] Charles Wenzel GPSDO

[Bruce Griffiths]

The monostable is a bit of a kludge.
Surely using a shift register to synchronise the PPS to 10MHz (or 1MHz) and 
comparing (using the same gated integrator arrangement) the synchroniser delay 
against a fixed pulse width generated by different taps on the same SR would be 
somewhat more stable? The fixed pulse width should be integer + 0.5 Shift 
Register clock periods. Ideally one would also remove the sawtooth error from 
the PPS before synchronising it.

Brucee 
 
> On 22 June 2017 at 12:50 paul swed  wrote:
> 
> 
> Love the flexibility and the simplicity. You could use about anything.
> Simple enough to try for fun.
> Regards
> Paul
> WB8TSL
> 
> On Wed, Jun 21, 2017 at 7:05 PM, Graham  wrote:
> 
> > Very cool.
> >
> > I too have a dislike for these coaxial type power connectors for just the
> > same reason, same goes for mini and micro USB and the like.
> >
> > I do use a lot of Power Pole connectors (crimped with a proper crimping
> > tool - not soldered) but in an application like this where there is
> > sufficient space I like to use 4 pin XLR connectors (Neutrik is my
> > preference). These are good for 10 amps, polarized, and lock in place and 4
> > pin simply because that is what I started to use many (many) years ago (3
> > pin for audio and 5 pin for data).
> >
> > cheers, Graham ve3gtc
> >
> >
> > On 2017-06-21 21:36, Brooke Clarke wrote:
> >
> >> Hi Chuck:
> >>
> >> I'd replace the push on DC power connector with a high force Power Pole.
> >> I can't count how many times one of these push on connectors has worked
> >> itself loose.
> >> http://www.prc68.com/I/PowerPole.shtml
> >>
> >>
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> > ailman/listinfo/time-nuts
> > and follow the instructions there.
> >
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Re: [time-nuts] Charles Wenzel GPSDO

[wb6bnq]

Chuck,

It is an analog version of the BROOK SHERA approach from almost 20 years 
ago.


BillWB6BNQ


Chuck / Judy Burch wrote:



I have been waiting for Charles Wenzel to get around to designing and 
building a GPSDO.  Well, he has done it now and you can see it at 
.


Any thoughts on the design relative to more conventional ones??


Chuck Burch
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Re: [time-nuts] Charles Wenzel GPSDO

[paul swed]

Love the flexibility and the simplicity. You could use about anything.
Simple enough to try for fun.
Regards
Paul
WB8TSL

On Wed, Jun 21, 2017 at 7:05 PM, Graham  wrote:

> Very cool.
>
> I too have a dislike for these coaxial type power connectors for just the
> same reason, same goes for mini and micro USB and the like.
>
> I do use a lot of Power Pole connectors (crimped with a proper crimping
> tool - not soldered) but in an application like this where there is
> sufficient space I like to use 4 pin XLR connectors (Neutrik is my
> preference). These are good for 10 amps, polarized, and lock in place and 4
> pin simply because that is what I started to use many (many) years ago (3
> pin for audio and 5 pin for data).
>
> cheers, Graham ve3gtc
>
>
> On 2017-06-21 21:36, Brooke Clarke wrote:
>
>> Hi Chuck:
>>
>> I'd replace the push on DC power connector with a high force Power Pole.
>> I can't count how many times one of these push on connectors has worked
>> itself loose.
>> http://www.prc68.com/I/PowerPole.shtml
>>
>>
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> time-nuts mailing list -- time-nuts@febo.com
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> ailman/listinfo/time-nuts
> and follow the instructions there.
>
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Re: [time-nuts] Charles Wenzel GPSDO

[Graham]

Very cool.

I too have a dislike for these coaxial type power connectors for just 
the same reason, same goes for mini and micro USB and the like.


I do use a lot of Power Pole connectors (crimped with a proper crimping 
tool - not soldered) but in an application like this where there is 
sufficient space I like to use 4 pin XLR connectors (Neutrik is my 
preference). These are good for 10 amps, polarized, and lock in place 
and 4 pin simply because that is what I started to use many (many) years 
ago (3 pin for audio and 5 pin for data).


cheers, Graham ve3gtc


On 2017-06-21 21:36, Brooke Clarke wrote:

Hi Chuck:

I'd replace the push on DC power connector with a high force Power 
Pole.  I can't count how many times one of these push on connectors 
has worked itself loose.

http://www.prc68.com/I/PowerPole.shtml



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

[Tom Van Baak]

> 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.

Mark,

There is misunderstanding on this topic so let me clarify.

1) The quasi-periodic relative motions of earth / moon / sun mean that the 
acceleration-of-gravity, aka little 'g' (~9.8 m/s^2), varies a tiny bit over 
hours, days, and months, roughly down at the 0.1 ppm level.

2) Since the period of a pendulum is approximately T = 2pi*sqrt(L/g), a tiny 
change in g results in a tiny change in T, at least in theory.

3) But as we all know from working with quartz and atomic oscillators there are 
many sources of frequency instability in a clock; they are generally additive; 
they tend to follow power-law noise types, and they are highly dependent on the 
averaging interval, or tau. The ADEV statistic nicely displays all of this in a 
single log-log plot. At any given tau a few noise sources are dominant; the 
rest are "lost in the noise".

For example, if your ADEV is 1e-6 then a 1e-9 2-g turnover effect is 
meaningless. Or if you have a 1e-9 tempco, then 1e-11 power supply variations 
are insignificant. And so on.

4) For most [*] pendulum clocks, the internal and external instability (noise) 
far exceeds the tiny effect of tides. Thus they do not and cannot "detect" 
tides. This is not a "big issue".

[*] To put this in perspective, so far we have digital records of only two 
pendulum clocks ever made that were stable enough so that the effect of tides 
is visible in their timekeeping. More info here: http://leapsecond.com/hsn2006/

/tvb

- Original Message - 
From: "Mark Sims" 
To: 
Sent: Tuesday, June 20, 2017 4:43 PM
Subject: [time-nuts] Plate Tectonics was: GPS Antenna on Tower.


> I'm using code from a Fortran program called solid.f  that I converted to C 
> using F2C and modified to use more accurate sun / moon positions.  The 
> solid.f  program is based on an edited version of the dehanttideinelMJD.f 
> source code provided by Professor V. Dehant. This code is an implementation 
> of the solid earth tide computation found in section 7.1.2 of the IERS 
> Conventions (2003) , IERS Technical Note No. 32.
> 
> http://geodesyworld.github.io/SOFTS/solid.htm
> 
> The gravity offset calculation is based upon TVB's  tides.c:
> 
> http://www.leapsecond.com/tools/tides.c
> 
> ---
> 
>> 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?


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Re: [time-nuts] CRT for Tracor 527A

[David C. Partridge]

My message to Dan Rea are bouncing, so please forgive the BW:

Dan,

Hang fire please - I just got this baby hooked up and there's been some 
creative wire cutting done.

The supplies for the CRT have been cut at the trafo.

It needs lots of TLC as its not actually working right now - fun ahead.

If I can get the basic function working then I'll get back to you about the 
tube.

PS Sympathies for the chemo BTW, Mary (my better half) has been there twice  ...

Dave

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Re: [time-nuts] GPS splitter

[Brooke Clarke]

Hi:

I just use a resistor.
http://www.prc68.com/I/DAGR.shtml#PS

and here is the Cable TV power divider were Type-F DC blocks are added to all 
but one of the output ports.
http://www.prc68.com/I/4GPS.shtml

--
Have Fun,

Brooke Clarke
http://www.PRC68.com
http://www.end2partygovernment.com/2012Issues.html

 Original Message 

Hi

Hitting the inductance required is relatively easy. Doing so and not hitting 
self resonance is a bit more tricky.
Even a zero ohm reactance likely will work ok (in series with a 150 ohm 
resistor).  It’s tough to know
what you have done without a network analyzer. It is even possible that your 
resistor has enough stray C
to mess things up. Of course it might also have enough stray L to get you back 
in business.

A somewhat less critical approach is to use ferrite beads on both sides of the 
resistor. They generally are a
bit less critical (= more likely to do what the data sheet claims). The trick 
there is to find some that are set up
to work at L band …. they aren’t common in my junk box.

Bob


On Jun 21, 2017, at 4:16 PM, Attila Kinali  wrote:

On Wed, 21 Jun 2017 15:03:54 -0400
Bob kb8tq  wrote:


The typical answer is: The largest one I could that 1) Would handle the short 
circuit current expected and
2) was self resonant at or above 1.6 GHz.

I found out, by experiment, that any "large enough" inductance is ok.
A simple "a few dozen windings of AWG30, air core and a tiny bit of
epoxy to keep the windings apart, yet stable" does the trick quite well.
At least it does for the bias-T I used it in. As a rule of thumb,
at the frequency you are using it, the inductor should have an
impedance much larger then the 50Ohm. And for 1.5GHz you get there
pretty quickly. E.g. 20-30 windings on 3mm spread to a length of 20mm
give you something in the order of 150 to 350nH, which translates
to 1k5 to 3k5 impedance at 1.5GHz.

I recommend reading [1] and [2] for the design of bias-T's
(there are probably better sources, but these are those
that I stumbled upon, some time ago)


Attila Kinali


[1] "Design of Bias Tees for a Pulsed-Bias, Pulsed-RF Test System
using Accurate Component Models", by Baylis, Dunleavy, Clausen, 2006
http://www.microwavejournal.com/articles/3912-design-of-bias-tees-for-a-pulsed-bias-pulsed-rf-test-system-using-accurate-component-models?v=preview

[2] "Wideband Bias Tee". by Johnson, 2008
http://wb9jps.com/Gary_Johnson/Bias_Tee_files/Bias_Tee_Design_V2R.pdf

--
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] Charles Wenzel GPSDO

[Brooke Clarke]

Hi Chuck:

I'd replace the push on DC power connector with a high force Power Pole.  I can't count how many times one of these push 
on connectors has worked itself loose.

http://www.prc68.com/I/PowerPole.shtml

--
Have Fun,

Brooke Clarke
http://www.PRC68.com
http://www.end2partygovernment.com/2012Issues.html

 Original Message 


I have been waiting for Charles Wenzel to get around to designing and building a GPSDO.  Well, he has done it now and 
you can see it at .


Any thoughts on the design relative to more conventional ones??


Chuck Burch
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Re: [time-nuts] CRT for Tracor 527A

[Bill S]

Dave,
I have a complete 527A with a slightly screwed up case (someone removed 
the handles and smoothed the edges!) that was working when I last used 
it about 6 years ago. The crt at the time was good and working. I had 
planned to put it on ebay but never got around to it. Email me off list 
if you're interested.

On 6/20/2017 5:01 PM, David C. Partridge wrote:

Trying a long shot here, I'm looking for a 1" CRT type 1EP1 (or 1EP11, or?)
for a Tracor 527A Frequency Difference Meter.
  
I did spot some on eBay but the vendor had a rather high opinion of their

worth :) at over 300 dollars

Anyone got one to spare?

Thanks
Dave

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

[Bob kb8tq]

Hi

There are some interesting interactions between liquid (sea) tides and solid 
tides. Big blobs of water sloshing around in the ocean 
really close to shore do turn out to have an effect. Not a big deal for those 
of us wise enough to live well inland :) Probably a lot of fun
to plot and validate if you are in the “right” location. 

One gotcha pulling this stuff from precision survey data: The post processing 
software very much knows about these things and 
“helpfully” scrubs them out of your data for you. That’s a not ideal if your 
goal was to validate the calculations. It sort of is if their 
result comes out as zero, but that’s not very exciting. 

Bob

> On Jun 20, 2017, at 7:43 PM, Mark Sims  wrote:
> 
> I'm using code from a Fortran program called solid.f  that I converted to C 
> using F2C and modified to use more accurate sun / moon positions.  The 
> solid.f  program is based on an edited version of the dehanttideinelMJD.f 
> source code provided by Professor V. Dehant. This code is an implementation 
> of the solid earth tide computation found in section 7.1.2 of the IERS 
> Conventions (2003) , IERS Technical Note No. 32.
> 
> http://geodesyworld.github.io/SOFTS/solid.htm
> 
> The gravity offset calculation is based upon TVB's  tides.c:
> 
> http://www.leapsecond.com/tools/tides.c
> 
> ---
> 
>> 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?
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Re: [time-nuts] GPS splitter

[Bob kb8tq]

Hi

Hitting the inductance required is relatively easy. Doing so and not hitting 
self resonance is a bit more tricky. 
Even a zero ohm reactance likely will work ok (in series with a 150 ohm 
resistor).  It’s tough to know 
what you have done without a network analyzer. It is even possible that your 
resistor has enough stray C
to mess things up. Of course it might also have enough stray L to get you back 
in business. 

A somewhat less critical approach is to use ferrite beads on both sides of the 
resistor. They generally are a 
bit less critical (= more likely to do what the data sheet claims). The trick 
there is to find some that are set up
to work at L band …. they aren’t common in my junk box. 

Bob

> On Jun 21, 2017, at 4:16 PM, Attila Kinali  wrote:
> 
> On Wed, 21 Jun 2017 15:03:54 -0400
> Bob kb8tq  wrote:
> 
>> The typical answer is: The largest one I could that 1) Would handle the 
>> short circuit current expected and
>> 2) was self resonant at or above 1.6 GHz.
> 
> I found out, by experiment, that any "large enough" inductance is ok.
> A simple "a few dozen windings of AWG30, air core and a tiny bit of
> epoxy to keep the windings apart, yet stable" does the trick quite well.
> At least it does for the bias-T I used it in. As a rule of thumb,
> at the frequency you are using it, the inductor should have an
> impedance much larger then the 50Ohm. And for 1.5GHz you get there
> pretty quickly. E.g. 20-30 windings on 3mm spread to a length of 20mm
> give you something in the order of 150 to 350nH, which translates
> to 1k5 to 3k5 impedance at 1.5GHz.
> 
> I recommend reading [1] and [2] for the design of bias-T's
> (there are probably better sources, but these are those
> that I stumbled upon, some time ago)
> 
> 
>   Attila Kinali
> 
> 
> [1] "Design of Bias Tees for a Pulsed-Bias, Pulsed-RF Test System
> using Accurate Component Models", by Baylis, Dunleavy, Clausen, 2006
> http://www.microwavejournal.com/articles/3912-design-of-bias-tees-for-a-pulsed-bias-pulsed-rf-test-system-using-accurate-component-models?v=preview
> 
> [2] "Wideband Bias Tee". by Johnson, 2008
> http://wb9jps.com/Gary_Johnson/Bias_Tee_files/Bias_Tee_Design_V2R.pdf
> 
> -- 
> 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
> ___
> time-nuts mailing list -- time-nuts@febo.com
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[time-nuts] Plate Tectonics was: GPS Antenna on Tower.

[Mark Sims]

I'm using code from a Fortran program called solid.f  that I converted to C 
using F2C and modified to use more accurate sun / moon positions.  The solid.f  
program is based on an edited version of the dehanttideinelMJD.f source code 
provided by Professor V. Dehant. This code is an implementation of the solid 
earth tide computation found in section 7.1.2 of the IERS Conventions (2003) , 
IERS Technical Note No. 32.

http://geodesyworld.github.io/SOFTS/solid.htm

The gravity offset calculation is based upon TVB's  tides.c:

http://www.leapsecond.com/tools/tides.c

---

> 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?
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Re: [time-nuts] GPS splitter

[Attila Kinali]

On Wed, 21 Jun 2017 15:03:54 -0400
Bob kb8tq  wrote:

> The typical answer is: The largest one I could that 1) Would handle the short 
> circuit current expected and
> 2) was self resonant at or above 1.6 GHz.

I found out, by experiment, that any "large enough" inductance is ok.
A simple "a few dozen windings of AWG30, air core and a tiny bit of
epoxy to keep the windings apart, yet stable" does the trick quite well.
At least it does for the bias-T I used it in. As a rule of thumb,
at the frequency you are using it, the inductor should have an
impedance much larger then the 50Ohm. And for 1.5GHz you get there
pretty quickly. E.g. 20-30 windings on 3mm spread to a length of 20mm
give you something in the order of 150 to 350nH, which translates
to 1k5 to 3k5 impedance at 1.5GHz.

I recommend reading [1] and [2] for the design of bias-T's
(there are probably better sources, but these are those
that I stumbled upon, some time ago)


Attila Kinali


[1] "Design of Bias Tees for a Pulsed-Bias, Pulsed-RF Test System
using Accurate Component Models", by Baylis, Dunleavy, Clausen, 2006
http://www.microwavejournal.com/articles/3912-design-of-bias-tees-for-a-pulsed-bias-pulsed-rf-test-system-using-accurate-component-models?v=preview

[2] "Wideband Bias Tee". by Johnson, 2008
http://wb9jps.com/Gary_Johnson/Bias_Tee_files/Bias_Tee_Design_V2R.pdf

-- 
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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[time-nuts] Charles Wenzel GPSDO

[Chuck / Judy Burch]

I have been waiting for Charles Wenzel to get around to designing and 
building a GPSDO.  Well, he has done it now and you can see it at 
.


Any thoughts on the design relative to more conventional ones??


Chuck Burch
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Re: [time-nuts] GPS splitter

[Bob kb8tq]

HI

The typical answer is: The largest one I could that 1) Would handle the short 
circuit current expected and
2) was self resonant at or above 1.6 GHz.

Bob

> On Jun 21, 2017, at 2:12 PM, David C. Partridge 
>  wrote:
> 
> Hi Magnus - what sort of inductor value did you use?  68nH or so?
> 
> Dave
> 
> -Original Message-
> From: time-nuts [mailto:time-nuts-boun...@febo.com] On Behalf Of Magnus 
> Danielson
> Sent: 17 June 2017 15:12
> To: time-nuts@febo.com
> Cc: mag...@rubidium.se
> Subject: Re: [time-nuts] GPS splitter
> 
> Hi,
> 
> At one time I had to design a DC-load since the GPSDO did not experience 
> enough antenna current due to a different antenna being used. So, a BNC-T was 
> quickly converted with a SMD inductor and resistor to add 150 Ohm of more 
> load, and that helped the telecom operator to get their GPS out of "no GPS 
> antenna" warning and actually accept the GPS satellites it was already 
> detecting fine.
> 
> Cheers,
> Magnus
> 
> On 06/17/2017 02:40 PM, Bob kb8tq wrote:
>> Hi
>> 
>> The DC block requirement depends a lot on the design of the GPSDO’s 
>> you are using. With some GPSDO’s a 50 ohm load on the eighth port of a 
>> splitter will do a pretty good job of “antenna detect” signaling. In 
>> the more general case of “I didn’t design this beast” dc blocks and dc 
>> shunts to ground is the best approach.
>> This fairly quickly gets you headed in the direction of the HP / 
>> Symmetricom splitters.
>> 
>> Bob
>> 
>> 
>> 
>>> On Jun 16, 2017, at 11:54 PM, Clay Autery  wrote:
>>> 
>>> This brings up some interesting questions:
>>> 
>>> If sharing an active GPS antenna, do you have to DC block all but one 
>>> receiver port to prevent multiple receivers trying to supply current 
>>> to the antenna?
>>> 
>>> On say a 26dB antenna (ignoring line loss, power divider insertion 
>>> loss, et al), what is the effective gain to each receiver?  (Sorry, 
>>> having a senior moment)
>>> 
>>> Should ALL unused ports have 50 ohm +/- 0j terminators on them?  I 
>>> assume so...  Thus, it would be "better" to always use the divider 
>>> with the minimum required ports?
>>> 
>>> I am assuming since this is a receive only situation, it will follow 
>>> approximately the same rules of physics that dealing with satellite 
>>> antenna installations.
>>> 
>>> I would LIKE to share one PC-TEL 26dB GPS antenna mounted at the top 
>>> of my 38 foot horiz.loop mast right  at the shack entrance, using 
>>> LMR-400-DB from antenna to Narda 2-way and thence to my current 
>>> hacked Nortel GPSDO and my soon to be complete RPi 2/3 w/ Adafruit 
>>> Ultimate GPS Hat NTP Server.  On that mast, the antenna would have a 
>>> near 360 degree view of the sky completely unobstructed.  
>>> (Eventually, I expect both of those units to be replaced with commercial 
>>> units).
>>> 
>>> I'm assuming that I DC block whichever unit is capable of providing 
>>> the LEAST current at 5VDC...  I suspect the Nortel unit can supply 
>>> more current than the RPi, but that's not a guarantee...  And I guess 
>>> I could block/turn off DC delivery on BOTH units and add a voltage 
>>> adjustable, current limiting DC injection unit into the line.
>>> 
>>> Thanks.
>>> 
>>> 73,
>>> 
>>> __
>>> Clay Autery, KY5G
>>> MONTAC Enterprises
>>> (318) 518-1389
>>> 
>>> On 6/16/2017 7:26 PM, Tim Lister wrote:
 On Fri, Jun 16, 2017 at 4:40 PM, Gregory Beat  wrote:
> I have reached the point that I need a 4-port splitter for my GPS antenna 
> (outdoor 5 volt).  Any recommendations of models 
> (HP/Symmertricom/Microsemi) to acquire OR to avoid??
 As we recommended to me when I asked a similar question, the Narda
 4372A-4 was a brand I had not heard of before and didn't come up in 
 'gps splitter' searches. I got one on ebay for $24 plus a bit extra 
 for DC blocks on the n-1 other ports and it seems to work well and 
 it was handy to have an SMA-based solution as most of the gps 
 receivers and the antenna pucks seem to use SMA. This meant I only 
 needed 1 N to SMA converter cable for an external antenna (which has 
 yet to be externalized...). I found it smaller in real life  than it 
 looks in a lot of the pictures, about the size of a modern 
 smartphone but about double or more the thickness (the connectors are on 
 the ends).
 
> greg
> ---
 Cheers,
 Tim
 ___
 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.
>> 
>> ___
>> time-nuts mailing list -- time-nuts@febo.com To unsubscribe, go to 
>> h

Re: [time-nuts] KS24019 units PSU requirements

[David C. Partridge]

Thanks, I ordered a 24V 120W power brick from eBay.

Dave

-Original Message-
From: time-nuts [mailto:time-nuts-boun...@febo.com] On Behalf Of Mark Sims
Sent: 21 June 2017 16:19
To: time-nuts@febo.com
Subject: [time-nuts] KS24019 units PSU requirements

I have not measured mine,  but I saw a spec of 2A max for each side mentioned 
somewhere (would drop considerably after warmup).  I am using a 24V 100W supply 
that came with my Z3811/Z3812 Lucent boxes.  It was already wired up with the 
proper connectors for the boxes.

--

> I  have a pair of L108 (RFTGm-II-Rb) and L109 (RFTGM-II-XO). 
What current do these bad boys draw so I don't get too skinny a 24V PSU?
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Re: [time-nuts] GPS splitter

[David C. Partridge]

Hi Magnus - what sort of inductor value did you use?  68nH or so?

Dave

-Original Message-
From: time-nuts [mailto:time-nuts-boun...@febo.com] On Behalf Of Magnus 
Danielson
Sent: 17 June 2017 15:12
To: time-nuts@febo.com
Cc: mag...@rubidium.se
Subject: Re: [time-nuts] GPS splitter

Hi,

At one time I had to design a DC-load since the GPSDO did not experience enough 
antenna current due to a different antenna being used. So, a BNC-T was quickly 
converted with a SMD inductor and resistor to add 150 Ohm of more load, and 
that helped the telecom operator to get their GPS out of "no GPS antenna" 
warning and actually accept the GPS satellites it was already detecting fine.

Cheers,
Magnus

On 06/17/2017 02:40 PM, Bob kb8tq wrote:
> Hi
>
> The DC block requirement depends a lot on the design of the GPSDO’s 
> you are using. With some GPSDO’s a 50 ohm load on the eighth port of a 
> splitter will do a pretty good job of “antenna detect” signaling. In 
> the more general case of “I didn’t design this beast” dc blocks and dc shunts 
> to ground is the best approach.
> This fairly quickly gets you headed in the direction of the HP / 
> Symmetricom splitters.
>
> Bob
>
>
>
>> On Jun 16, 2017, at 11:54 PM, Clay Autery  wrote:
>>
>> This brings up some interesting questions:
>>
>> If sharing an active GPS antenna, do you have to DC block all but one 
>> receiver port to prevent multiple receivers trying to supply current 
>> to the antenna?
>>
>> On say a 26dB antenna (ignoring line loss, power divider insertion 
>> loss, et al), what is the effective gain to each receiver?  (Sorry, 
>> having a senior moment)
>>
>> Should ALL unused ports have 50 ohm +/- 0j terminators on them?  I 
>> assume so...  Thus, it would be "better" to always use the divider 
>> with the minimum required ports?
>>
>> I am assuming since this is a receive only situation, it will follow 
>> approximately the same rules of physics that dealing with satellite 
>> antenna installations.
>>
>> I would LIKE to share one PC-TEL 26dB GPS antenna mounted at the top 
>> of my 38 foot horiz.loop mast right  at the shack entrance, using 
>> LMR-400-DB from antenna to Narda 2-way and thence to my current 
>> hacked Nortel GPSDO and my soon to be complete RPi 2/3 w/ Adafruit 
>> Ultimate GPS Hat NTP Server.  On that mast, the antenna would have a 
>> near 360 degree view of the sky completely unobstructed.  
>> (Eventually, I expect both of those units to be replaced with commercial 
>> units).
>>
>> I'm assuming that I DC block whichever unit is capable of providing 
>> the LEAST current at 5VDC...  I suspect the Nortel unit can supply 
>> more current than the RPi, but that's not a guarantee...  And I guess 
>> I could block/turn off DC delivery on BOTH units and add a voltage 
>> adjustable, current limiting DC injection unit into the line.
>>
>> Thanks.
>>
>> 73,
>>
>> __
>> Clay Autery, KY5G
>> MONTAC Enterprises
>> (318) 518-1389
>>
>> On 6/16/2017 7:26 PM, Tim Lister wrote:
>>> On Fri, Jun 16, 2017 at 4:40 PM, Gregory Beat  wrote:
 I have reached the point that I need a 4-port splitter for my GPS antenna 
 (outdoor 5 volt).  Any recommendations of models 
 (HP/Symmertricom/Microsemi) to acquire OR to avoid??
>>> As we recommended to me when I asked a similar question, the Narda
>>> 4372A-4 was a brand I had not heard of before and didn't come up in 
>>> 'gps splitter' searches. I got one on ebay for $24 plus a bit extra 
>>> for DC blocks on the n-1 other ports and it seems to work well and 
>>> it was handy to have an SMA-based solution as most of the gps 
>>> receivers and the antenna pucks seem to use SMA. This meant I only 
>>> needed 1 N to SMA converter cable for an external antenna (which has 
>>> yet to be externalized...). I found it smaller in real life  than it 
>>> looks in a lot of the pictures, about the size of a modern 
>>> smartphone but about double or more the thickness (the connectors are on 
>>> the ends).
>>>
 greg
 ---
>>> Cheers,
>>> Tim
>>> ___
>>> 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] GPScon running on Raspberry Pi 3b

[Mark Sims]

Lady Heather can run under Linux, macOS,  FreeBSD, and Windoze.   It runs well 
on the PI (2 or 3) and the soon to be released version 6 has support for the 
touchscreen and several new devices.   I can send anybody interested in testing 
the new version the latest source code to build.  Contact me off list.

New devices include the RFTG-m,  Truepostion GPSDO,  Zyfer Nanosync 380,  
Brandywine GPS4, Jackson Labs LTE-lite,  Oscilloquartz Star-4,  NEC GPSDO,  
Trimble TAIP receivers, most SCPI GPSDOs (Z38xx, HP-5),  HP-5071A,  TAPR 
TICC,  HP-531xx counters,  generic time/frequency counters,  etc

--

> I believe that having a native GPS monitoring software on a Raspberry Pi 
> instead of PC would become a game changer.
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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 discipline oscillator vs phase lock

[Brent]

Jim -

Your first thread in this post was fascinating to me - stuff I'd never been
exposed to.  It seems like the 'tricks of the trade' for so much of how
things actually get done are so often only accessible to those who work
closely with them.  I was about to shoot you an email to ask if there was
any reference (other than piles of journal articles) that cover some of
these topics, when I scrolled down and found this post with the Descanso
links and references.  What a trove!  There's more info in the links on
that page than I could ever hope to comprehend.

Many thanks for this post.  It will remain marked and in the back of my
brain as "stuff that you should learn".  If we only ever had enough time.
Why didn't anyone ever expose me to this stuff when I was young and just
starting in RF?

Brent



On Sun, Jun 18, 2017 at 1:36 PM, jimlux  wrote:

> On 6/18/17 7:10 AM, Attila Kinali wrote:
>
>> On Sat, 17 Jun 2017 06:29:02 -0700
>> jimlux  wrote:
>>
>> Well, at JPL we regularly lock two crystal oscillators together that are
>>> over a billion km apart with added Allan deviation of less than 1E-15 at
>>> 1000 seconds with a radio link at 7.15 GHz.  It's how we measure the
>>> distance and velocity to spacecraft (a few cm in range and mm/s in
>>> velocity) and from that figure out the gravitational fields (among other
>>> things)
>>>
>>
>> This sounds interesing. What do I have to google for to learn more?
>>
>>
> It's just how we do radio science/ranging - you transmit a spectrally pure
> signal from earth (typically oscillator locked to a maser), at the
> spacecraft you have a very narrow band PLL (traditionally a VCXO) that
> locks to the received signal, and you generate the downlink signal from
> that same oscillator, transmit it back to earth, and compare.
>
> The transmitted signal is precisely in a specified ratio with the received
> signal (880/749 for X-band 7.15 GHz from earth, 8.4 GHz coming back). For
> Ka-band, the earth signal goes up at 34 GHz, and comes back at 32 GHz
>
> A typical spec is that the transponder introduce no more than 4E-16 ADEV
> at 1000 sec.
>
>
> https://descanso.jpl.nasa.gov/ has links to a whole bunch of useful
> references
>
> https://descanso.jpl.nasa.gov/monograph/mono.html
> specifically volume 1 by Thornton and Border talks all about radiometric
> ranging.
>
> The various design and performance series describe the specific
> implementations.
>
> Joe Yuen's "Deep Space Telecommunications Engineering"
> https://descanso.jpl.nasa.gov/dstse/DSTSE.pdf
> Chapter 3 covers receiver design
> Chapter 4 covers radio tracking
>
> --
>
> Then you can look for papers on "deep space transponder"  The classic
> design papers are in the 90s.   IEEE MTT, and the JPL IPN progress reports.
>
> The Cassini Deep Space Transponder is sort of a progenitor of them - then
> there's the Small Deep Space Transponder (SDST) designed in the 90s, flying
> 2000 through now.
>
> Somewhere around 2000, the design started moving away from trying to lock
> the oscillator to doing the phase lock and phase/frequency turnaround in a
> digital loop, with a fixed oscillator driving DDS or NCO.  At JPL, this
> would be the "Advanced Deep Space Transponder", but Thales Alenia Space
> Italia (TASI) uses a similar approach for their deep space transponders
> (look for Juno and BepiColombo)
>
>
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[time-nuts] KS24019 units PSU requirements

[Mark Sims]

I have not measured mine,  but I saw a spec of 2A max for each side mentioned 
somewhere (would drop considerably after warmup).  I am using a 24V 100W supply 
that came with my Z3811/Z3812 Lucent boxes.  It was already wired up with the 
proper connectors for the boxes.

--

> I  have a pair of L108 (RFTGm-II-Rb) and L109 (RFTGM-II-XO). 
What current do these bad boys draw so I don't get too skinny a 24V PSU?
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[time-nuts] KS24019 units PSU requirements

[David C. Partridge]

I have a pair of L108 (RFTGm-II-Rb) and L109 (RFTGM-II-XO). 

What current do these bad boys draw so I don't get too skinny a 24V PSU?

Thanks
Dave

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Re: [time-nuts] SR620/PM66xx/CNT-90 input stages

[Charles Steinmetz]

Bruce wrote:


If the source impendance at dc is 10k at dc a bias current of a few
microamp produces a dc offset of tens of millivolts which may be an
issue if the signal amplitude is low and has a low slew rate.


Jeez, Bruce, it was nothing but a thought experiment to illustrate why 
an amplifier's DC input current is not a reliable proxy for input 
impedance  It was not a suggestion for how to design an amplifier input. 
 And that should have been obvious to you -- I'm sure it was to 
everyone else.


Get a life.

Charles


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Re: [time-nuts] SR620/PM66xx/CNT-90 input stages

[Bruce Griffiths]

Your assumptions about my comment are unfounded. It was just intended as an 
additional reason as to why direct connection to a comparator input isnt a good 
idea with a high source impedance. The original post asked why a buffer was 
needed.

 Bruce

> 
> On 21 June 2017 at 22:14 Charles Steinmetz  wrote:
> 
> Bruce wrote:
> 
> > > 
> > If the source impendance at dc is 10k at dc a bias current of a few
> > microamp produces a dc offset of tens of millivolts which may be an
> > issue if the signal amplitude is low and has a low slew rate.
> > 
> > > 
> Jeez, Bruce, it was nothing but a thought experiment to illustrate why
> an amplifier's DC input current is not a reliable proxy for input
> impedance It was not a suggestion for how to design an amplifier input.
> And that should have been obvious to you -- I'm sure it was to
> everyone else.
> 
> Get a life.
> 
> Charles
> 
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Re: [time-nuts] SR620/PM66xx/CNT-90 input stages

[Attila Kinali]

Moin,

On Tue, 20 Jun 2017 17:11:24 -0400
Charles Steinmetz  wrote:

> I was going tp post the Smith chart for the input of the AD96885/7 ECL 
> comparator they use, but was surprised to find that AD did not include 
> it on the datasheet.  However, just from the spec table we can see why a 
> buffer is necessary:
> 
> Input Resistance:   200k ohms
> Input Capacitance: 2pF

Thanks everyone! I was caught again in my DC line of thinking.
Even though I saw the capacitance spec, it didn't registers.

At some point I need to learn how to design RF circuits


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.

[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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