Re: [time-nuts] 4046 replacement

[EB4APL]

Hi,

When I was going to build a Brooks Shera's GPSDO in 2009, I ordered from 
him some parts that I needed. He graciously added a couple of Texas 
Instruments' 74HC4046AE that was used in the phase detector because, 
according to him, these parts from other manufacturers would not work 
correctly.


Regards,

Ignacio, EB4APL



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Re: [time-nuts] PBS, Tue evening, The Secret of Tuxedo Park

[EB4APL]

Joe,
Thank you for the pointer. The regular web site don't allow the series 
to be viewed outside USA.


73 de Ignacio, EB4APL


El 17/01/2018 a las 2:47, Joseph Gray escribió:

If you want to watch this episode online, go here:
http://video.unctv.org/video/3008204310

This is the UNC Public TV web site.

Joe Gray
W5JG



On Tue, Jan 16, 2018 at 2:28 PM, Bill Tracey <b...@ewjt.com> wrote:


To record OTA television I use an HDHomeRun :
https://www.silicondust.com/hdhomerun/

I'll grab tonight's run of The Secret of Tuxedo Park

Cheers,

Bill

At 09:04 AM 1/16/2018, you wrote:


I can't stress enough how important Loomis was to the history of precise
timekeeping in early radio, telephone, pendulum clock, quartz oscillator
era. And for those of us who still have Loran-C receivers can thank him
(Loomis Radio Navigation -> LRN -> Loran).
.

If someone knows how to record any time/clock/navigation parts of PBS
show for non-US viewers let me know, off-list.

/tvb





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Re: [time-nuts] TruePosition on the Arduino

[EB4APL]

Maybe I'm missing something, but Arduino programs are usually 
distributed as source code. If this is the case, the I2C address of the 
display should be not a problem.  If the problem is due to the display 
library used, you can use another library that can be initialized with 
the right address.

I'm curious about the real problem.

Regards,
Ignacio, EB4APL


El 26/06/2017 a las 2:29, Tom Miller escribió:
This is an update to discussions off list with Ben and Chris regarding 
using the two line, 16 character display with the Packrats software on 
the Arduino to control the TruePosition GPS board.


First, the ebay seller still has a few boards left and seems to take 
offers of $40 for them.


Second, the display used with the Packrats software must use the I2C 
address of 0x3F to work. The display needs to use the PCF8574AT I2C 
I/O expander chip and not the PCF8574T. The later chip addresses 
between 0x20 to 0x27 and will not work with this software.


Third, I picked up some of the "A" chips on ebay and they were marked 
as A chips but addressed wrong. If you are going to change out this 
expander chip, get them from someone like Mouser.


Next step is to find a suitable housing for this assembly.

Thanks all,
Tom


- Original Message - From: "Ben Hall" <kd5...@gmail.com>
To: "Discussion of precise time and frequency measurement" 
<time-nuts@febo.com>

Sent: Tuesday, June 06, 2017 7:46 PM
Subject: [time-nuts] TruePosition on the Arduino



Good evening all,

There is a saying: "a man with one watch knows the time, a man with 
two is never sure."  Clearly, this man wasn't a timenut and didn't 
have GPS.  ;)


I've been working on the Arduino code for the TruePosition boards 
that quite a few of us have bought from the e-place.


It's my first real foray into both Arduino and the C language. (About 
a million years ago I was reasonably competent with FORTRAN...the 
1977 version...)  It's mostly working - I can receive and display 
pretty much everything that comes out of the unit minus a few 
parameters.  I can display it all on three pages on a 4 line by 20 
character I2C display. Currently, the pages are selected by grounding 
out one of two pins, or having nothing grounded.  Eventually, I'm 
going to change this so that it changes display pages when a button 
is pressed.  I don't have lat/long display yet, nor can I handle 
doing a survey, but those are coming.


My code probably would make a real programmer vomit, but hey, it 
works. :)


Back to the man with multiple watches.  I was having a very 
frustrating issue with my TruePosition and Arduino code being one 
second behind my other sources of time.  I went round and round, 
trying to figure out why the TruePosition thru the Arduino was a 
second slow.  In the end, it turns out that it wasn't slow...it was 
correct...but that my other sources of time have errors.


I finally proved this to myself by firing up an old Trimble Lassen LP 
GPS board unit equipped with a 1PPS tick light and serial 
output...and it was clear that it matched the TruePosition after 
correcting for the fact that my TruePosition / Arduino code only 
updates the display when 1PPS is asserted high...but that the Lassen 
LP displays the serial message before it becomes valid at the next 
1PPS tick.


I was slightly embarrassed...I should have known that the other 
sources of time all had sources of error beyond my control.  I should 
have trusted the TruePosition as being the purest, least complicated, 
and the path I knew the most about between GPS and my eyeballs.


So for a while...the statement was true.  With my multiple sources of 
time...I really didn't know the time.  But it was also untrue, as 
when I got agreement between two very "pure" sources of time, I knew 
everything else was wrong.  ;)


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
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Re: [time-nuts] Specifications (Service manual?) for HP 00105-60xx oscillators?

[EB4APL]

Hi Ulf,

I don't have a service manual, I think that it does not exist since HP 
stated that it was not a field maintainable item and any attempt to 
adjust it would void the warranty. Anyway I have a schematic and a brief 
circuit description from the HP 105 manual, which uses the 00105-6013 
oscillator.


This oscillator was also used in the 5065A Rb standard. Its manual has a 
section devoted to this oscillator including theory of operation, 
operational checks and schematics.


The HP 5061A Cesium standard also used this oscillator and its manual 
includes schematics and a section about testing this oscillator.


I can extract the pertinent sections and schematics from the referred 
manuals if you think that it could be useful.


Regards,

Ignacio, EB4APL


El 13/05/2017 a las 17:40, Ulf Kylenfall via time-nuts escribió:
  
Gentlemen.

I have the excellent manual for the 10811-oscillatorswhich includes the specs 
for the different versions.
I have searched for a similar document for theolder 00105-60xx ocillators but 
there seems to benone.
Preparing for the 5065A restoration, I have a coupleof 00105-60xx oscillators 
and I would like to knowthe difference between them.
Ulf KylenfallSM6GXV
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Re: [time-nuts] NTGS50AA No Serial

[EB4APL]

I had a stupid problem with mine when doing some tests and I had the 
same symptoms and it took me several days of tests to realize the problem.


The original flat cable that goes to the auxiliary board with the panel 
lights and the RS-232 connector has the pins reversed so if you connect 
the pin one to pin one you still get some LEDs on but no comms. Connect 
it as per the attached photo.  If the list deletes the attachments, 
please ask me to send it directly.



El 15/04/2017 a las 13:11, Bryan _ escribió:

Have you tried different serial settings I wonder if the hard reset mucked 
things up. have a Nortel as well, never had a issue with a reset but try 
changing a few thing sup. It may need the unusual 19200,7,Odd and 1 stop bit 
setting.


If you try a terminal program do you at least see some garbage characters?

-=Bryan=-



From: time-nuts  on behalf of Ed Armstrong 

Sent: April 15, 2017 1:13 AM
To: Discussion of precise time and frequency measurement
Subject: [time-nuts] NTGS50AA No Serial

My NTGS50AA is suddenly lacking the ability to communicate. It's been
working fine for months, but I was trying a few things with my Raspberry
Pi NTP server.

Had GPSD accessing the NTGS50AA through a ch340 USB to serial adapter.
Found out Lady Heather displays much less info when connecting through
GPSD, so I went back to LH connecting directly to NTGS50AA through ch340
adapter on windows 7. Curiously, it was surveying, not in position lock.
So, I did a hard reset. Never heard from it since :(

If it's unplugged, all the lights behave as they should when you power
it up again. "Locked" light eventually comes on. PPS still works. Just
no serial. Even tried Trimble Studio with auto detect settings, no
connect here either. I've tried a second ch340 USB to serial adapter,
same deal. Any suggestions?

Thanks
Ed
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Re: [time-nuts] NTGS50AA No Serial

[EB4APL]

I had a stupid problem with mine when doing some tests and I had the 
same symptoms and it took me several days of tests to realize the problem.


The original flat cable that goes to the auxiliary board with the panel 
lights and the RS-232 connector has the pins reversed so if you connect 
the pin one to pin one you still get some LEDs on but no comms. Connect 
it as per the attached photo.  If the list deletes the attachments, 
please ask me to send it directly.



El 15/04/2017 a las 13:11, Bryan _ escribió:

Have you tried different serial settings I wonder if the hard reset mucked 
things up. have a Nortel as well, never had a issue with a reset but try 
changing a few thing sup. It may need the unusual 19200,7,Odd and 1 stop bit 
setting.


If you try a terminal program do you at least see some garbage characters?

-=Bryan=-



From: time-nuts  on behalf of Ed Armstrong 

Sent: April 15, 2017 1:13 AM
To: Discussion of precise time and frequency measurement
Subject: [time-nuts] NTGS50AA No Serial

My NTGS50AA is suddenly lacking the ability to communicate. It's been
working fine for months, but I was trying a few things with my Raspberry
Pi NTP server.

Had GPSD accessing the NTGS50AA through a ch340 USB to serial adapter.
Found out Lady Heather displays much less info when connecting through
GPSD, so I went back to LH connecting directly to NTGS50AA through ch340
adapter on windows 7. Curiously, it was surveying, not in position lock.
So, I did a hard reset. Never heard from it since :(

If it's unplugged, all the lights behave as they should when you power
it up again. "Locked" light eventually comes on. PPS still works. Just
no serial. Even tried Trimble Studio with auto detect settings, no
connect here either. I've tried a second ch340 USB to serial adapter,
same deal. Any suggestions?

Thanks
Ed
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Re: [time-nuts] Time Dilation tinkering

[EB4APL]

Not mentioning that the clock traveled in a passenger seat (even with 
the seat belt fastened). The vision of a big box with  cables and a good 
sized clock ticking (it was a Patek Philippe movement in early HP 
Cesiums) frightened some passengers  and the person accompanying the 
clock had to give a lot of explanations. The use of the word "atomic" 
worsened things somewhat.


(Memories from Apollo flights good times)

Regards,

Ignacio, EB4APL



El 23/03/2017 a las 12:33, Bob Camp escribió:

Hi

Back before GPS and similar systems, hauling Cs standards on commercial 
aircraft was
a bit more common than it is today. One of the critical tricks of the trade was 
knowing where
each power outlet was on a specific plane and how close it was to this or that 
seat. The next
trick was knowing how to talk the crew into letting you plug the gizmo in the 
seat next to yours
into that outlet. Sometimes the magic worked and other times you had to depend 
on your
battery pack. Needless to say, getting through the over ocean travel process 
with a dead
standard was not good news.

Bob


On Mar 22, 2017, at 10:59 PM, Bob Bownes <bow...@gmail.com> wrote:

It's not getting one past the airport authorities that's the issue. It's 
getting one that's powered up past them. ;)

Written from about 10,000'. :)


On Mar 22, 2017, at 20:15, Tom Van Baak <t...@leapsecond.com> wrote:

Chris Albertson wrote:

Why drive up a mountain?

"Because it's there" ;-)  And because there's a paved road, and it's free, and 
there's a place to stay overnight, and the mountain doesn't move. Plus a car makes a good 
portable time lab; you can share the experience with family or students or visiting time 
nuts; and a number of technical reasons.

But most importantly: you can remain at altitude as long as you want -- in 
order to accumulate just enough nanoseconds of time dilation to meet your 
experiment's S/N goal -- without running into (or much worse, going beyond) the 
flicker floor of your clocks.

There are several different ways to measure time dilation with atomic clocks. 
Some notes here:
http://leapsecond.com/pages/atomic-tom/



Take the clock with you inside the pressurized cabin of a commercial airliner

Yes, and this has been done many times. The first (1971) and most famous of all 
traveling clock relativity experiments is:
https://en.wikipedia.org/wiki/Hafele%E2%80%93Keating_experiment

For vintage hp flying clock articles see:
https://www.febo.com/pipermail/time-nuts/2013-January/073743.html

Two modern examples are described here:

"Time flies"
http://www.npl.co.uk/news/time-flies

"Demonstrating Relativity by Flying Atomic Clocks"
http://www.npl.co.uk/upload/pdf/metromnia_issue18.pdf

/tvb

- Original Message -
From: Chris Albertson
To: Tom Van Baak ; Discussion of precise time and frequency measurement
Sent: Tuesday, March 21, 2017 7:12 PM
Subject: Re: [time-nuts] Time Dilation tinkering

"flight" there is the word.Why drive up a mountain?   Take the clock with 
you inside the pressurized cabin of a commercial airliner next time you are on one of 
those 10 hour trans=pacific flights.   You be taller then any mountain and it is actually 
cheaper then a weather balloon.

Can you get a Rb clock past the TSA x-ray machine.   Maybe if you ask first.  
There must be a way to hand cary specialized equipment.

On Tue, Mar 21, 2017 at 7:03 PM, Tom Van Baak <t...@leapsecond.com> wrote:

But attached is one of the first plots where I put a SA.32m in a home-brew 
vacuum chamber and pulled down to a few inches of Hg for a few hours to 
simulate the low pressure of a flight up to 50 or 90,000 ft. For a high 
altitude relativity experiment -- where you'd like your clock to remain stable 
to parts in e-13 and not accumulate too many stray ns -- it's not a good sign 
when your clock changes by 2e-11 (that's more than 1 ns per minute) just 
because of ambient pressure changes.


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Re: [time-nuts] OT: Eagle PC CAD now Autodesk, $500/year

[EB4APL]

Graham,

Thank you for your tip.

Regards,

Ignacio, EB4APL


El 21/01/2017 a las 17:26, Graham / KE9H escribió:

Your existing Eagle license should allow you to run your existing version
indefinitely.
I think it would be useful for a few years or so.

I also think your existing license also allows you to run one copy on Mac,
Linux or Windows.
So, if you are on Windows 7 and think you might want to migrate to Linux or
Mac,
go download a copy of the other installers NOW.

They have pulled down the Version 7.7 and all earlier version archive
access on the main
Eagle and AutoCad site, but the cadsoft ftp server is still up and
serving.  I don't expect
AutoCad to allow that to happen for much longer.

ftp://ftp.cadsoft.de/eagle/ <ftp://ftp.cadsoft.de/eagle/program/7.7/>
ftp://ftp.cadsoft.de/eagle/program/7.7/

Running real slow, (overloaded?) so be patient.

The biggest issue with migrating to KiCad for me is walking away from ten
years of
"trusted" parts footprints.  Hopefully an Eagle to KiCad footprint
translator would
become available.

I don't do enough hobby and incidental work to justify the $500 per year
that it would
take to replace my previous $125 every three years or so "Non-profit"
license.

--- Graham

==



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Re: [time-nuts] No sat positions in LH with Trimble NTBW50AA?

[EB4APL]

I'm using /rxt for my NTBW50AA and after reading your message I changed 
it to /rxy.
I got the same problems as Pete described, so I returned to Thunderbolt 
mode.


Regards,
Ignacio, EB4APL

El 05/01/2017 a las 18:41, Mark Sims escribió:

The Nortel devices can talk either as a Thunderbolt or as a SCPI device.  Use 
it as a Thunderbolt (/rxt).   In SCPI mode the satellite positions are polled 
for once a minute (at xx:xx:33).  Thunderbolt mode provides much more and 
better control of the receiver.

---


  I just got my Trimble NTBW50AA GPSDO up and running with Lady Heather 5.0.

However I don't see any satellite data as I do with my Resolution T.   I
am using
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Re: [time-nuts] No sat positions in LH with Trimble NTBW50AA?

[EB4APL]

Hi Pete,

I have a NTBW50AA running with Lady Heather 5.0 (and also with previous 
version) and I don't see any anomaly, it sees all satellites in view and 
the clock updates every second. BTW, I have done a mod for outputting 1 
PPS instead of 1/2 PPS, but it does not go to LH.


I can only suggest you to test it using Trimble Visual Timing Studio to 
have a "second opinion".


Regards,

Ignacio, EB4APL


El 05/01/2017 a las 15:25, Peter Reilley escribió:
I just got my Trimble NTBW50AA GPSDO up and running with Lady Heather 
5.0.
However I don't see any satellite data as I do with my Resolution T.   
I am using

/rxy which specifies SCPI-(NORTEL) as the device.

What am I doing wrong?

Also, the clock updates every 2 seconds.   I assume that this is an 
artifact of the

2PPS output.

Thanks,
Pete.

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Re: [time-nuts] Version 5 wrong leap second

[EB4APL]

Mine showed 01:00:60 but it is configured to Madrid LT, so it means 
00:00:60 UTC also. My receiver is a Trimble NTGS50AA, close cousin of a 
Tbolt.


Ignacio, EBA4PL


El 01/01/2017 a las 1:33, Pete Stephenson escribió:

On Sun, Jan 1, 2017 at 1:28 AM, Bill Beam  wrote:

My LH v5.00 showed leap second as 00:00:60 on a Tbolt. Not good

Previous June 2015 LH v3.10 correctly showed 23:59:60

If interested, I have screen captures.

Now that you mention it, so did mine...
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Re: [time-nuts] Anyone (ideally in the UK) got a spare rotary knob for the 5370B TI counter?

[EB4APL]

Hi,

I'm not totally sure about the limits, but I have read several times 
that in the UK the nominal supply voltage is 230 V +10%/−6% to 
accommodate the fact that most supplies are in fact still 240 V. The 
context was that a lot of test equipment failed when operated at around 
250 V and many input capacitors (particularly the ones inside a know 
brand IEC socket - filter) caught fire.


Wikipedia says that several areas in UK still have 250 V because this 
value is withing the current limits.


I think that the governing document is British Standard BS 7697: Nominal 
voltages for low voltage public electricity supply systems — 
(Implementation of HD 472 S1).


Regards,

Ignacio, EB4APL



El 31/12/2016 a las 11:25, Dr. David Kirkby (Kirkby Microwave Ltd) escribió:

On 31 Dec 2016 02:03, "Bob Stewart" <b...@evoria.net> wrote:

If you can touch the heat sink for 2 seconds, you're made of sterner

stuff than I am!  They run very hot.  It's a good idea to get a GPIB
extender so your GPIB cable can clear the heat sink.  Somebody, can't
remember who, worked up a nice looking conversion to a pair of switching
supplies.

SMPSs tend to be less clean than a linear supply. I would be somewhat
reluctant to take that route on test equipment. But I will search for the
conversion.

I have a 13 A variac sitting around that's not been used in the last 25
years. I think as a short term measure I will drop the voltage to a few
bits of the equipment with linear power supplies. The spectrum analyzer has
linear supplies and puts out a lot of heat.  As someone else said,  a 20 V
transformer would work. Adding the variac will take me 5 minutes to do,
which has an advantage over anything I need to build.

I will also log the mains voltage over a period of a few weeks and see if
it high enough to ask the electricity supply company to do something about
it.  I do know someone that measured his voltage and found it was outside
the legal limits. He advised the electricity supplier,  they agreed,  but
said that they were not going to do anything about it.  He wired his whole
house on an auto transformer.  I would be speaking to my Membrr of
Parliament (MP) if it was outside the legal limits. I don't know what legal
limits exist in the UK for voltage,  but I can find out.

It is unusual in the UK for a domestic property to have a phase supply, but
mine does.  I don't know whether any one phase is consistently lower than
any other. If so phases could be switched.  But given my close promptly to
the 11 kV transformer,  I doubt it.

I know at one point I had a dispute with the electricity supply company as
the 415 V overhead power lines used to be regularly hit by farm vehicles
down a private road where my property is. This would pull the cables away
from my house and make a mess of the house. The electricity supplier would
always repair the damage,  but after this happened a few times I
complained. I was initially told they would do nothing as it is not a road.
But I discovered that the cables needed to be a minimum height if there was
vehicular access. So whether the electricity supplier considered it a road
or not was irrelevant.  Eventually they extended a pole and raised the
cables up, which appears to have solved the problem.  Whether I can
convince them to move the transformer taps is another matter.  I suspect
that it might be hard if my supply is consistently high, but not outside
the legal limits.

Dave
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Re: [time-nuts] Ublox M8N - have I a XO or TCXO ?

[EB4APL]

TCXO is not an OCXO, they don't have an oven. They compensate the 
temperature induced drift using a temperature sensor, a microcontroller  
and a table or parameter set for adjusting the output frequency. BTW, 
for some applications they are unsuitable as they adjust the frequency 
in steps.



Regards,

Ignacio EB4APL

El 21/12/2016 a las 20:29, Mike Millen escribió:


>>>> Can anyone comment on the following data, and whether they think the


oscillator in "my" M8N is a XO or a TCXO ?



Can you monitor the current draw from cold (ambient)?

You may be able to identify the initial steady current drawn by the TCXO
heater, then the cycling once it's hit the right temp?

If there's no change at all in average current as it warms then it may
not have a TCXO.

Mike


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Re: [time-nuts] Trimble UCCM survey results

[EB4APL]

Elevation differences between GPS receivers usually come from the 
elevation reference used, i.e. from the ellipsoid or the geoid, even 
from the geoid being used.


Regards,

Ignacio , EB4APL


El 20/12/2016 a las 7:28, Tom Curlee escribió:

A couple of questions:
I've just started using  LH 5.0 with my 2  GPSDO units (Thanks Mark!) - a 
Trimble UCCM and a Z3801A.  Oddly, I'm very getting different survey altitude 
values.  The Z3801A is around 81 M, which agrees within 1 or 2 meters with 
Google maps (not a perfect source, but close), but the UCCM is usually around 
48M to 53M depending on which survey I want to believe.  Both receivers are 
locked and both are fed off the same antenna through a splitter.  I admit that 
the antenna placement is very poor - anything below 60 degrees elevation to the 
north is blocked (LH is great for antenna placement analysis).  Anyone have any 
ideas?
A question on LH usage.  When the UCCM is in the position hold mode, what 
happens when a precision survey is run?  Looking at the .lla file shows that 
every position, including the final processed location,  is the same as that 
shown as the position hold location on the main LH screen.  Do you need to take 
the receiver out of the hold mode to run a precision survey?  How?  How is the 
position scatter plot used with a survey?  I usually don't see any positions 
plotted, certainly not when running a precision survey.  I think I saw data 
plotted when I did an internal survey.
Many thanks for any info.  And thanks again to Mark and John for all the work.
Tom


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Re: [time-nuts] Do reflections up/down the antenna cable cause a problem with GPS?

[EB4APL]

I believe that reflections inside the cable (that is, after the antenna) 
are very different from reflections before the antenna. GPS receivers do 
their calculations based in the different arrival times of the 
satellites signals to the antenna center, so delays caused from 
different paths caused by reflections on external objects really 
matters. Reflections inside the cable, where phase relationships between 
the signals is already fixed, does not matter, or at least, not very much.


I don mean to disregard matching, which can cause big signal level 
losses if it is very bad.  BTW, GPSDO's like the popular Thunderbolt, 
are meant to use 75 Ohm cable and connectors but 50 Ohm cable can be 
used without much difference.   The PPS phase with respect to UTC, witch 
is affected by the cable delay, must be adjusted with the corresponding 
parameter. I think that a cable delay measurement could be more useful 
in this regard.


Anyway, I can be wrong and if it is the case, I would like comments from 
the experts here.


Best regards,

Ignacio, EB4APL


El 21/11/2016 a las 14:45, Dr. David Kirkby (Kirkby Microwave Ltd) escribió:

People state it is desirable to have a GPS antenna well clear of
obstructions, which I believe is to stop reflections. But there is another
source of reflections which I suspect could be just as problematic.

Whilst the input impedance of the antenna input terminal on a GPS receiver
is probably marked 50 Ohms, I'd be somewhat surprised if it was very close
to 50 Ohms. Antenna cables have an impedance, which is typically 50 +/- 2
Ohms, but this varies, not only between different makes/models of cables,
but even on the same real of cable.The output of the pre-amp is most
unlikely to have a 50 Ohm source impedance. In fact, the output impedance
might be close to 0 Ohms, as it may be driven by a voltage source, without
any 50 Ohm resistor.

Anything not immediately absorbed by the GPS receiver is going to be
reflected back up the coax, and could be reflected multiple times.

I just looked on my HP 8720D VNA, and see I can reduce the output power to
-70 dBm, which would should not do any damage. It will be interesting to
see just what the input impedance of the GPS receiver is. I'm tied up with
doing my accounts over the next few days, but later I will look.

If reflections on the antenna/cable/receiver are a problem, then
attenuators can improve the match, but of course they reduce the signal
level too. A more intelligent, but more difficult solution, is to build a
matching network. For that one would need a VNA to measure the impedance in
the first place.

Dr. David Kirkby Ph.D CEng MIET
Kirkby Microwave Ltd
Registered office: Stokes Hall Lodge, Burnham Rd, Althorne, Essex, CM3 6DT,
UK.
Registered in England and Wales, company number 08914892.
http://www.kirkbymicrowave.co.uk/
Tel: 07910 441670 / +44 7910 441670 (0900 to 2100 GMT only please)



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Re: [time-nuts] Do reflections up/down the antenna cable cause a problem with GPS?

[EB4APL]

I believe that reflections within the cable doesn't matter regarding  
the GPS measurements, unlike the reflections coming from outside the 
antenna. The measurements are made from the differences in the arrival 
times of the different satellite signals to the antenna and delays after 
that basically does not affect them. Well, the cable delay affects to 
the phase of the PPS but this is accounted for in a parameter.


Anyway, I don't mean that a good matching is something that can be 
totally disregarded and if the mismatch is very large it will affect to 
the signal lever at the receiver input but not to the measurement 
mechanism. BTW some GPSDO's, the Thunderbolt being an example, are 
supposed to be feed with 75 Ohm antenna cable with F connectors.


I may be be totally wrong, but in that case I'll appreciate comments 
from more knowledgeable people.


Best regards,

Ignacio, EB4APL



El 21/11/2016 a las 14:45, Dr. David Kirkby (Kirkby Microwave Ltd) escribió:

People state it is desirable to have a GPS antenna well clear of
obstructions, which I believe is to stop reflections. But there is another
source of reflections which I suspect could be just as problematic.

Whilst the input impedance of the antenna input terminal on a GPS receiver
is probably marked 50 Ohms, I'd be somewhat surprised if it was very close
to 50 Ohms. Antenna cables have an impedance, which is typically 50 +/- 2
Ohms, but this varies, not only between different makes/models of cables,
but even on the same real of cable.The output of the pre-amp is most
unlikely to have a 50 Ohm source impedance. In fact, the output impedance
might be close to 0 Ohms, as it may be driven by a voltage source, without
any 50 Ohm resistor.

Anything not immediately absorbed by the GPS receiver is going to be
reflected back up the coax, and could be reflected multiple times.

I just looked on my HP 8720D VNA, and see I can reduce the output power to
-70 dBm, which would should not do any damage. It will be interesting to
see just what the input impedance of the GPS receiver is. I'm tied up with
doing my accounts over the next few days, but later I will look.

If reflections on the antenna/cable/receiver are a problem, then
attenuators can improve the match, but of course they reduce the signal
level too. A more intelligent, but more difficult solution, is to build a
matching network. For that one would need a VNA to measure the impedance in
the first place.

Dr. David Kirkby Ph.D CEng MIET
Kirkby Microwave Ltd
Registered office: Stokes Hall Lodge, Burnham Rd, Althorne, Essex, CM3 6DT,
UK.
Registered in England and Wales, company number 08914892.
http://www.kirkbymicrowave.co.uk/
Tel: 07910 441670 / +44 7910 441670 (0900 to 2100 GMT only please)
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Re: [time-nuts] Man with too many clocks.

[EB4APL]

I agree that FE-5680 is a whole family of products with very different 
features and these can not deducted from the labels.


In my case I own a FE-5680A which outputs 1 PPS and a fixed (but 
slightly tunable) 10 MHz and needs 2 power supply voltages, +5 V and + 15 V.


I am sending directly to you the information of the breakout board that 
I use and it includes the pinout of this unit.  A caution here, some of 
the FE-5680 variations have different pinouts.


Regards,

Ignacio EB4APL


El 05/11/2016 a las 2:01, Peter Reilley escribió:
It is a FE-5680B.   It is my understanding that these were made in 
many variations
of features but that what features were present or absent could not be 
known
from the model numbers of other external identifying information. This 
one

has the 1 PPS apparently.

Pete.



On 11/4/2016 1:07 PM, EB4APL wrote:
A bit OT, but regarding your Rb, some units needs to be powered thru 
2 pins, one is used only for the 10 MHz output buffer, if remember it 
correctly. Which is your model number?


Ignacio EB4APL


El 04/11/2016 a las 16:35, Peter Reilley escribió:
I gave up on trying to use the GPS 1 PPS signal to calibrate the 10 
MHz OCXO's that
I have.   The reason that others have pointed out is that the 
uncorrected 1 PPS
signal from the GPS is has just a little too much a jitter to use it 
for calibration
with your eye using a scope.   If it were sawtooth corrected then it 
would be better

but you really need a GPS disciplined oscillator.

Not to be outdone, I brought out a rubidium oscillator that I had 
put away because
it did not appear to work properly.   It only put out a 1 PPS signal 
and nothing else.
I compared that with the GPS PPS and could get a good comparison on 
the scope.
The rubidium drifted about 40 nS over 12 hours.   So it seemed to be 
good.


With that I could adjust the OCXO's in my 5370's.   The spec for the 
HP 5370B with
a HP 10811 OCXO is better than 1 X 10^-10 RMS for 1 sec average. 
That is, it should
take more than 1,000 seconds for one 10 MHz wave to shift by 360 
degrees.   That
is very hard to do using the screw adjustment in the OCXO. Even the 
slightest
movement possible will cause a frequency change greater that is 
spec'ed.   How

do cal labs do it?

My HP 5370A has a 10544 OCXO which is spec'ed for short term 
stability of
better than 1 X 10^11 for 1 second.   Even better than the 5370B! 
The adjustment
screw is much coarser and it is not possible to get any better than 
a few seconds for
one cycle phase shift of the 10 MHz OCXO against the standard. It 
seems that I can't

get even close to the spec.

These have been running for a few days.   It that enough?

Pete.



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Re: [time-nuts] Questions on Nortel Trimble NTBW50AA GPSTM

[EB4APL]

Hi,

Sorry for this late response but I was away from home.
I did the 1 PPS mod a year ago. I just cut the trace between TP14 and 
U405 pin 6 and soldered a wire between TP14 and TP33.
Now you have 1PPS on the former 9.8304 MHz output. Not being a cellular 
tower operator I did not have any use for this frequency.
Comparing the 1PPS with the .5 PPS pulses, there are an offset, which is 
not constant.  In my case it can be 540, 440, 340, 240 or 140 ns, it 
changes before locking but after the lock condition it remains constant. 
Studying the circuit and the Nortel specs, the 1/2 PPS must be 
synchronous with the 9.8304 MHz signal, so this is probably the cause.  
I still have to check with an independent  1PPS reference (a Rb one) to 
see if this PPS is reliable.


Regards,
Ignacio EB4APL


El 10/08/2016 a las 21:25, Clay Autery escribió:

1) Need a 24 VDC power supply.  Am considering just buying an Astron
VLS-35M Adjustable Voltage/Current supply (5-32V/1.5A to limit) since I
don't own a variable power supply yet, this is a linear, and the same
size package as my RS-70M.  I can worry about a dedicated supply later
if I decide to keep this GPSTM after I finish modding/testing it.

Anyone have any recommendations to the contrary?  Why?

2) Need to bring the PPS out from the TP in this article:
https://www.i3detroit.org/wiki/Nortel_GPSTM  The article shows a buffer
circuit being used to accomplish this...  Need help locating a datasheet
on the Motorola chip used...  It's obsolete and I need to find a pin
compatible replacement...

Or, I need to find another buffer schematic/plan,

Or, alternatively  has anyone ever tried pulling the 1pps out and
hooking it to the 9.8 MHz driver (severing the drive line to it and
jumpering in the 1pps)?  The 9.8MHz and the 10MHz signal out ports SEEM
to use identical driver/buffer circuits on this board...  Seems like a
possibility...

Preferably, I find the Motorola chip, copy the buffer circuit and move
on...

I'm pretty new at this, so any help is appreciated, and not slapping me
about for "not knowing" stuff is greatly appreciated!  :)

Sincerely,



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Re: [time-nuts] HP 5360A History?

[EB4APL]

Are you referring to the 00105-6013? I have one and its info.

Ignacio, EB4APL


El 15/04/2016 a las 8:31, cdel...@juno.com escribió:

The oscillator used in the 5360A is the same one used in the early 105A,
the 5061A and the 5065A.
I just call them the 105 style oscillator. They have a 115 volt
thermoswitch controlled fast warmup heater that is set to switch out once
it gets close to the set point of the proportional controller oven that
stays on all the time. 10811A units are better performers.

Cheers,

Corby


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Re: [time-nuts] Prescaler

[EB4APL]

The first reference is a board for a two stage divider.  They mention 
that a /2 and a /5 chips can be combined, so you can make a /10 prescaler.


Regards,
Ignacio, EB4APL


El 27/03/2016 a las 23:24, Dave M escribió:

Bob Albert via time-nuts wrote:

Does anyone know of an inexpensive prescaler for a counter that goes
beyond 2 GHz? I would actually like to find a kit but everything
seems a bit pricy. I currently have capability of 500 MHz and that
will stretch to about 700 with care. So a divide by 10 would be
ideal.




If you're good at kit-building, you might take a look at the Ebay 
items 160703629055, 181982380658, 400265187641, and 60703624281. These 
are PCBs made to specifically fit a number of frequency divider 
chips.  Each board holds a single divider chip and associated 
components, such as the decoupling caps, bias resistors, and pads for 
interconnections.
A series of these boards that add up to a divide-by-100 can get you to 
2 - 5GHz easily. I've never used any of these boards or dividers, but 
I have used a few of the seller's amplifier boards, with great success.


There's also a construction article from Silicon Chip magazine (Oct, 
2006) dedicated to constructing a 2.8 GHz 1000:1 prescaler for 
counters.  The PCB layout and all the active parts are available.  
Send me an email for a copy of the article.


I don't know of any prescaler chips that get you a divide-by-10 
prescaler at your target frequency range.  There might be (probably 
is) one available... I just haven't run across it.


BTW, which frequency counter do you have?  There might be a better 
solution for you than an external prescaler.


Cheers,
Dave M


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Re: [time-nuts] MTI 260-0624-D OCXO

[EB4APL]

I have read sometime ago and probably on this list a success stories 
about opening OCXOs using a hot air gun or even a propane torch, an 
x-acto knife  and a stainless steel shim sheet to avoid the solder to do 
it stuff again when solidifying.
Using this technique probably the can could be reused after repairing 
the part.


Ignacio EB4APL



El 19/02/2016 a las 18:09, time...@metachaos.net wrote:

Alex,

I did not take opening pictures, but there is nothing to miss.

For the outside of the unopened case, there are plenty of pictures on eBay.
For the actual opening process, that consisted largely of scraping away solder
with a small, triangular file and utility knife until most of what I could
remove was gone and then using a hammer and screwdriver to separate the sides
from the bottom and then prying it off. Nothing pretty, and nothing much for
pictures. I used a tiny drill for my desoldering gun to remove an intial hole
in the solder for the adjustment hole. I then enlarged it with a 1/16th drill
bit (by hand). Ideally, a 2mm drill bit could be used. A 5/64th drill bit will
fit through the hole, but it is very tight. Probably not best to drill with
it because that would most likely enlarge the hole.

I wouldn't open it the same way again, but I'm not sure of the best procedure
that leaves the case and contents undamaged so that it can be reassembled. I
think, perhaps, that I would remove all of the solder that I could as before.
But then, I would make some sort of cut-out for the pins on the bottom and put
it in a pan on the stove and heat it up (hopefully, evenly) until the bottom
could be popped off. The outside case can get pretty hot without damage
because the only contact is the pins and the inside gets pretty hot when
running. The main risk is getting so hot that the plastic spacers on the pins
melt or the pin supports melt. I'm not sure how hot that would be. But, they
must have heated it fairly hot to melt the solder originally, so hopefully
that would work.

However, here are some pictures of the inside :) which is probably what you
want!

Top Case 1:[img]http://imgur.com/mvQkJ16[/img]
Top Case 2:[img]http://imgur.com/K7Rmeau[/img]
Bottom Case 1: [img]http://imgur.com/j7tC7QN[/img]
Bottom Case 2: [img]http://imgur.com/TKiofvi[/img]
Outer Oven 1:  [img]http://imgur.com/bzYywj7[/img]
Outer Oven 2:  [img]http://imgur.com/kKKynzc[/img]
Outer Oven 3:  [img]http://imgur.com/xtzFsXD[/img]
Circuit Board: [img]http://imgur.com/PHgnVIm[/img]


Mike



Hi Mike,
Would you be so kindly and post some pictures of the opening process of
that OCSXO ?
73
KJ6UHN
Alex
On 2/18/2016 7:54 PM, time...@metachaos.net wrote:

Bob,

The vendor has said that they did not want the unit back. So...

I opened it up. Crudely, I admit. I learned a few things. I was concerned
about the outer case heating up too much when I was trying to remove the
solder. Turns out that the outer case doesn't touch anything except the pins,
so it can get pretty hot without any damage. Unfortunately, I used a bit of
brute force to remove the casing after scraping away as much of the solder as
I could and after cracking the solder seal with a hammer and screw driver.
Even using more heat, I'm not sure of the best way to remove the case. Neither
solder wick nor a vacuum desoldering tool is likely to remove all of the
solder between the top case and the bottom.

Even so, I got the case off. Somewhat bent, even bent the bottom circuit board
a bit. I discovered that there is a 2mm hole in the top that allows a variable
resistor to be adjusted. You need a pretty long, small screwdriver / adjusting
tool to do that, but that is probably for setting the center point. I would
try to remove the solder rather than drilling, or drill upside down to prevent
solder flakes from falling inside.

Also, I found that the -D on my part number appears to correspond to the board
revision, which is marked "Rev D". So the -C and -D parts probably have the
same specifications. And, on the inside there is a marking "92.0" which I
believe would be the set point for this specific crystal. So if I took the
crystal out, I would know where to design the set point for a custom unit
(currently beyond my skills, but who knows...).

  From there, I removed the bottom casing. That caused additional damage, some
lifted traces and even one very small part (tiny, SMD, who knows?).

But, I then soldered wires directly to the board, making patches for the
lifted traces.

I plugged it in.

I turned it on.

Success!

I gave it 12v which should supply 2A, but it dropped the voltage down to just
over 9V. Even so, I got a nice sine wave out at around 4.999790Mhz according
to my (uncalibrated) scope and around 800mV (into 50 ohm, DC). That was with
nothing attached to the adjustment pin. After some time, the frequency
stabilized at 5.14Mhz and the voltage came back up to 10v. When I attached
the adjustment pin to ground, there was no change. When I attache

Re: [time-nuts] Glass Envelope Quartz Crystals

[EB4APL]

Here is a picture of one of those British made glass envelope crystals 
with miniature 7 pin bases.  It is marked 62.500 KC/S and came from an 
old Marconi broadcast B/W TV sync generator.

https://www.dropbox.com/s/3jtadg2c9rlc42n/Glass%20crystal.jpg?dl=0

Ignacio, EB4APL


On 03/02/2016 a las 22:41, Ian Stirling wrote:

On 02/02/2016 03:24 PM, Don Latham wrote:
You have it right, iovane. At the least, they should be protected 
from light,
thermal radiation, and emf.   Won'drous things will happen if the 
crystal and
its structure are subjected to radiation through the glass. I'd 
suggest a foam gator

wrap in a tin can as a minimum. Put the oscillator cat in there too.


  I have a 100 kHz glass "Crystal Unit" made by G.E.C., type JCF/193
with a serial number and sealed in a valve/tube with seven pins.
I removed it from my Eddystone EA12 that I bought from Tom Roberts,
G3YTO, SK 1985. It has a black shield with a spring inside at the top
so that it grips the base. The valve that produced 100 kHz markers for
dial calibration failed and I don't use the EA12 these days.
It will be interesting to see how stable it is and what the effect
of light and heat on it is when I start experimenting.

Ian, G4ICV, AB2GR
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Re: [time-nuts] moon bounce for synchronization

[EB4APL]

We were not measuring frequency but clock offset.  The frequency offset 
was estimated from the daily clock measurements.

If I remember correctly we got .1 uS accuracy.
We had several Rubidium, Cesium and later a H-maser frequency standards 
and we kept continuous recordings (strip charts) of the phase differences.
The transmitter precompensation kept care of combined Doppler (Moon 
motion and Earth rotation, which is the main component).  We operated at 
X band, the transmitting antenna had 85 ft or maybe less, I don't know 
exactly and the transmitter probably had 20 Kw.
By contrast the receiving antenna was small, I found at a picture 
(http://www.douglasvanbossuyt.com/2009/07/19/goldstone-dsn-complex-tour/) of 
one that looks the same, at least the dish and pedestal are almost 
identical.
I forgot to say that this system was abandoned in favor of VLBI which 
gave more accuracy and a lot more useful info.  Both systems had the 
drawback that the monitoring was not continuous and needed a lot of 
resources at both ends.  By contrast Loran-C and GPS used existing 
infrastructure that was continuously available. BTW, I don't know how 
Loran-C stations were synchronized, this came granted by the Navy.
We also used once a traveling clock, it was an HP cesium, the one with a 
Patek-Philipe clock on the front. The crew who operated it told us funny 
stories about the clock traveling on commercial jet seats and afraid 
passengers asking  about this bomb looking device and being told that it 
was some kind of "atomic" thing.


Regards,
Ignacio



On 31/01/2016 a las 2:21, jimlux wrote:

On 1/30/16 4:27 PM, Hal Murray wrote:


eb4...@gmail.com said:
Back to the Control Room you contact the transmitting station (I 
think  it

was DSS12) by voice to insure that they have the station manned and
transmitting, and began to operate the "thing". The transmission were
specific for each receiving station, because all the complex 
processing  was
done at the transmission end: the transmitting equipment accounted  
for the
instantaneous round trip distance between the transmitter and the 
receiver
via the moon and continuously adjusted the modulating code "early" 
in order
to to be received on time.  The equipment also  introduced a one 
microsecond
shift each second. The receiver had a  correlator whose output went 
to an HP
strip chart recorder which draw  the correlator output in one 
channel and a

PPS with a minute mark in the  second.


What sort of frequency accuracy were you after?

Did somebody have to correct for the Doppler due to the rotation of 
the Earth?


I'm pretty sure they did. Ignacio can say for sure.

We precompensate on transmit to get the signal to arrive at the 
spacecraft at its "best lock frequency". Or, actually slightly off, 
then we ramp through the BLF so the receiver can acquire the carrier. 
The receiver bandwidth might be as narrow as a few 10s of Hz, so you 
don't want to be too far off or ramp too fast.


On S-band (2-2.3GHz), the earth rotation Doppler is about 2-3kHz. 
(0.5km/sec), depending on latitude and where the Moon is in the sky.


If you're doing the Moon, you put its motion via a SPK file into the 
algorithm.  In 1970, that would have been a bit more tedious. 
With the moon, it depends on what part of the moon you're aiming at, too.


Last year (March 3rd), I was doing an experiment bouncing a DSN signal 
from Goldstone off the moon and receiving it at JPL. As I recall, the 
"spot" on the moon was about 800km in diameter. For what it's worth, 
you don't need a particularly good receiver when your transmitter is 
20 kilowatts into a 34m antenna (DSS 24).


Since our transmit and receive site were pretty close together, the 
Doppler of earth motion wasn't much, but there was Lunar Doppler, on 
top of that, there's libration.



Chuck Counselman did a bunch of work with VLBI type techniques using 
various ground stations around the world to determine where things 
(like the lunar rover) were on the surface of the moon.

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Re: [time-nuts] moon bounce for synchronization

[EB4APL]

I was a lot of times at the other side of the link, the receiving end, 
those days (and I also have no hair).
The procedure was cumbersome: you have to climb to the roof to manually 
point a small parabolic antenna to the moon using handwheels and a rifle 
scope. The antenna had an hourangle electrical drive which moved it at 
sidereal rate through a differential gear and a variable speed motor so 
you can select an offset to the rate that matched the moon motion at the 
time.
Back to the Control Room you contact the transmitting station (I think 
it was DSS12) by voice to insure that they have the station manned and 
transmitting, and began to operate the "thing". The transmission were 
specific for each receiving station, because all the complex processing 
was done at the transmission end: the transmitting equipment accounted 
for the instantaneous round trip distance between the transmitter and 
the receiver via the moon and continuously adjusted the modulating code 
"early" in order to to be received on time.  The equipment also 
introduced a one microsecond shift each second. The receiver had a 
correlator whose output went to an HP strip chart recorder which draw 
the correlator output in one channel and a PPS with a minute mark in the 
second.
If everything went OK we recorded several ramps from the correlator 
output, and here comes where the fun started: we had to adjust the noisy 
ramp to a straight line and extrapolate it to the zero crossing. 
Counting the seconds from the minute mark + 30 up to the zero crossing 
we got the local clock offset.
Fortunately we relied on Loran C as our main clock offset determination 
method until the arrival of GPS.


Good old times.

Ignacio, EB4APL and former DSN engineer.



El 30/01/2016 a las 20:19, jimlux wrote:

On 1/30/16 10:43 AM, Jeremy Nichols wrote:

Ooh! Ooh! Not only a 5245 with a 5265 voltmeter plug-in but a 5360
Computing Pig! Great picture, thanks for posting it.

Jeremy
N6WFO


I like how none of the push buttons in the panel below the counters 
have labels, either on the faceplate or on the button themselves.


I'll see if I can track down more info. That handsome devil of an 
engineer in the picture probably still works at the lab (albeit with 
gray or no hair).  Heck, the rack with the instruments is probably 
still out at Goldstone and being used.  It's old enough that it 
doesn't have the new inventory barcodes on it, though.


I just checked, and there are no pieces of property with the 5360 in 
the model number.  So that piece of gear may have been excessed.


There are, however, 3 of the 5245 counters around, and judging from 
the location codes, I think they're still out at the DSN sites or 
similar. No 5265s in the database, but they may not have been 
separately inventoried.


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Re: [time-nuts] Generating a solid PPS from 10Mhz source

[EB4APL]

Hi,

We are drifting from the original problem (dividing 10 MHz to 1 PPS) to 
general questions such as hardware vs software implementation, 
obsolescence of parts, program data retention and big program sizes for 
trivial tasks, all of them also interesting.


Well, returning to the main problem I just checked the original PPSDIV 
program source from TVB in order to remind me the size of the code:
360 lines of assembler text code including everything even blank lines.  
This accounts for 62 lines of text header with a detailed explanation of 
how the program works which even include the schematic drawn in 
character graphics and 302 lines of code including comments.  Pruning 
this code of comment and blank lines it leaves 182 lines of executable 
code.
This is the original PPSDIV code made for a PIC with more I/O pins that 
divides the 10 MHz input to 9 simultaneous outputs from 100 KHz to .001 
Hz, all of them synchronous.
The smaller versions made for 8 pin chips has about  97 lines of 
assembler code including everything.  This accounts for 46 lines of text 
header and 51 lines of code including comments.  Pruning this code of 
comment and blank lines it leaves 31 lines of executable code (well, 
and  a little more since I have a subroutine missing).
For personal use you can stock a couple of PICs if you are  afraid of 
their availability in case of a future failure.


Regards,
Ignacio




On 17/01/2016 a las 1:40, jimlux wrote:

On 1/16/16 10:07 AM, Poul-Henning Kamp wrote:


In message 
<20160116080037.13903406...@ip-64-139-1-69.sjc.megapath.net>, Hal 
Murray writes:



kb...@n1k.org said:
The astonishing part of this “new world” is that a very complex 
chip that is
made in high volume is cheaper than a handful of less popular (but 
far less

complex) chips.


It would be interesting to see the die sizes.


Die size is not really an issue until they become big enough to 
impact overall yield.


And apropos:  I just used a LPC810, to do 5MHz to 1Hz for my HP5065A 
clock.  It almost
feels surreal to use a 32bit ARM CPU, even in a DIP8, for something 
so mundane...




And how many thousand lines of code (including libraries, etc. that 
may have been pulled in)?


I had just this discussion yesterday at work with someone.   These 
days, silicon (even going into space) is much cheaper than people. 
Sure, you could optimize a hand crafted little routine in assembler. 
Or, you could just load up RTEMS, compile your program, link in 
newlib, etc., and have it working in a day.  If you've got 2 MByte of 
memory, nobody cares whether you use 1kbyte or 50kbyte.

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Re: [time-nuts] Einstein Special on PBS

[EB4APL]

Hi John,

Thank you very much for this explanation, I found it very "explicative".
What I am not able to grasp is the sense of the phrase " That second 
part was what really baked peoples' noodles".  I think that is some 
colloquial but not being English my native language I can't figure out 
its meaning.


Thank you,
Ignacio


El 27/11/2015 a las 21:54, John Miles wrote:

So, here's how I finally grokked this stuff.  c, the speed of light in a vacuum, is often 
spoken of as a "speed limit" that nothing can ever exceed.  That's a bad way to 
put it, and people who have expressed it that way in popular science writing for 100 
years should feel bad.

Instead, the way to visualize relativity is to realize that c is the *only* 
speed at which anything can travel.  You are always moving at 300,000,000 
meters per second, whether you want to or not.  But you're doing it through all 
four dimensions including time.  If you choose to remain stationary in (x,y,z), 
then all of your velocity is in the t direction.  If you move through space at 
100,000,000 meters per second in space, then your velocity in the t direction 
is 283,000,000 meters per second (because sqrt(100E6^2 + 283E6^2) = 300E6.)

It doesn't make sense to speak of moving a certain number of "meters" through time, so 
your location in time itself is what has to change.  You won't perceive any drift in your personal 
timebase when you move in space, any more than you will perceive a change in your location relative 
to yourself.  ("No matter where you go, there you are.")  But an independent observer 
will see a person who's moving at 100,000,000 meters per second in x,y,z and 283,000,000 meters per 
second in t.   They see you moving in space, in the form of a location change, and they also see 
you moving in time, in the form of a disagreement between their perception of elapsed time and your 
own.

Likewise, if you spend all of your velocity allowance in (x,y,z), your t 
component is necessarily zero.  Among other inconvenient effects that occur at 
dt/dt=0, you won't get any closer to your destination, even though your own 
watch is still ticking normally.  Particles moving near c experience this 
effect from their point of view, even while we watch them smash into their 
targets at unimaginable speeds.

This is special relativity in action.  The insight behind general relativity is 
twofold:  1) movement caused by the acceleration of gravity is 
indistinguishable from movement caused by anything else; and 2) you don't even 
have to move, just feel the acceleration.  That second part was what really 
baked peoples' noodles.  It is what's responsible for the disagreement between 
the two 5071As.

-- john, KE5FX
Miles Design LLC




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Re: [time-nuts] More HP5065 experiments

[EB4APL]

Hi Poul-Henning,

According to your linked info I understand that you don't have 
schematics and more info about the 105 OCXO.
The HP 105 and HP 5065A don't include any information, treating it as a 
module that is not field reparable, but the HP 5061A Cesium Frequency 
Standard manual, while stating  the same, does include this info both in 
theory of operation and schematics.

If you don't have this manual at hand I can send you these info from mine.

Regards,
Ignacio EB4APL


El 27/09/2015 a las 9:46, Poul-Henning Kamp escribió:

Discovery of the day:  The voltage supplied to the Rb87 lamp changes
the frequency on the order of 1.5e-11 per volt.

I have no idea why...

 http://phk.freebsd.dk/hacks/HP5065A/index.html



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Re: [time-nuts] FE-5680A pin 6?

[EB4APL]

Hi Nick,

FE-5680A is a whole family of Rb oscillators that have in common the 
case and name but the functionality, connectors and inner stuff varies a 
lot.  Some are programmable on a wide frequency margin, others has a 
fixed frequency output, mostly 10 MHz.  The connector arrangement also 
varies but you probably are referring to one with the P/N 217400-30352-1.
These units have a 1 PPS output on pin 6, the signal is normally at 0 
volts with a 1 uS wide 1PPS at about 5 volts.  This low duty cycle 
signal is difficult to see on an analog scope but you can see the 
trigger light blinking at each pulse.
The 1PPS signal is buffered by U503, a 74ACT240SC-ND chip. A word of 
caution here: since the driver circuitry is shared with the Lock output, 
an excessive (ie. a LED) load on the lock pin cause the 1PPS to 
disappear.  Please recheck the output voltage on pin 6, -5 volts doesn't 
make any sense for me, even with a driver chip failure (I have busted 
mine some time ago by connecting the +15 V power supply to the 5 volts 
input, a consequence of the disperse information about these units that 
circulate on Internet. Apparently on some units pin 6 is the +5 volt 
input so you can also ruin the driver following this wiring list.
If you are interested I have the board schematics that was reverse 
engineered by a member of this list who unfortunately I cannot give 
credit because I don't remember who is.  I can send it it directly to 
you if you want it.


Regards,
Ignacio EB4APL


El 11/09/2015 a las 3:06, Nick Sayer via time-nuts wrote:

I’ve acquired an eBay 5680. I’ve hooked it up to +15 and +5 and am getting 10 
MHz out and the test pin is low. The unit is warm and within any reasonable 
expectations, it appears to be working properly.

What I wonder about is pin 6 on the connector. Google results seem to indicate 
that that’s supposed to be a PPS output, but what I get on it is a fixed -5v or 
so. Anybody know what this signal is supposed to be?

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[time-nuts] FE-5680A commands

[EB4APL]

Hello,

I was wondering if anybody has the full command set for this Rb 
oscillator.  I know that FE-5680A means very different things and some 
commands are unit type dependent, but I think that there should be 
commands to monitor some health data, something similar to the LPRO-101 
and FRS-C which have analog outputs of the lamp and oscillator voltages.
Also since this unit has a 1PPS output, maybe a means of steering it is 
built in.
I have the FE-5680A Calibrator program by Bob Campbell VK4XV, but it 
only uses the offset commands, maybe others have developed other 
programs or at least have the command info.


Regards,
Ignacio EB4APL
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Re: [time-nuts] NTGS50AA 1 PPS mod

[EB4APL]

I uploaded the partial schematic and some other info to:
https://www.dropbox.com/s/k23e3x00ypnlx67/NTGS50AA%20info.zip?dl=0
You don't need to have a dropbox account to download it, just follow the 
link.


Regards,
Ignacio




El 17/06/2015 a las 3:20, EB4APL wrote:

Hi,

I has been making some tests with the 1 PPS output and here are the 
results:


Lady Heather cable delay commands works with both polarities, i.e. it 
can advance or retard both 1/2 and 1 PPS signals, I used as reference 
and external 1 PPS signal from a Rb oscillator.
The first impression is that the 1 PPS  edge leads the 1/2 PPS about 
550 ns and this difference is consistent after some cable delay 
commands and antenna disconnections, it is maintained during holdover.
Then I tried several power cycling and warm resets and this make an 
annoying thing to appear: during the acquisition and phase locking the 
difference jumped between 540 and 140 ns in 100 ns steps.  This is due 
to the 1/2 PPS synchronization with the SYS_CLOCK signal, so when the 
internal 1/2 PPS moved back and forth until the system phase lock is 
obtained, the output jumps between successive cycles of the 
SYS_CLOCK.  The annoying thing is that its final state is not always 
the same, the final difference can be any of the mentioned steps, from 
120ns to 550 ns and there is not guarantee which one is obtained while 
in my board the 540 ns difference is the most common.  I don't know 
yet  it the 1 PPS is closer to the epoch second or it is the 1/2 
PPS, I have to hook up a GPS timing module and an antenna splitter and 
see what happens. Anyway since Nortel specifies a tolerance of +/- 1 
us of the 1/2 PPS with respect to GPS even second, any of the seen 
values are within specs but it is not very convenient for Time Nuts.


Regards,
Ignacio

El 14/06/2015 a las 20:35, EB4APL wrote:
Even if I get a cell site I would not use it for a private network, 
here all cell phones are GSM not CDMA.
The only use for the 9.8304 MHz is as a master for deriving serial 
comm clocks (i.e. 9600 is  9.8304 / 1024) but I don't plan to became 
a Serial Comm Time Nut yet. ;-)


Ignacio


El 14/06/2015 a las 1:48, Bob Camp escribió:

Hi

Of course tomorrow you will stumble into a “great deal” on a 
complete cell site that needs a 9.8304 MHz clock :)




One thing to watch:

The pps you now have may or may not be deterministic in its relation 
to the every other second output. It also may or
may not be in a fixed relation to GPS. I would bet money that it 
*is* in a fixed relation and that it’s actually better than
the other signal. Just because I believe it to be true does not make 
it true. It needs to be checked against something else.


Bob



On Jun 13, 2015, at 1:56 PM, EB4APL eb4...@gmail.com wrote:

Hi,

I just finish the mod.  It was easy, I cut the trace between TP14 
and U405-6 and soldered a wire between TP14 and TP33. Now I have a 
pretty 1 PPS on J5, the old 9.8304 MHz output. The signal has 0-5 V 
levels, normally high with a 10 us pulse going down.  In my unit 
this pulse leads the even second pulse by 539 ns.  I will check if 
the Lady Heather command for compensating the cable length can be 
used to move this if somebody needs a more accurate epoch second. 
I have to use the 1PPS from my FE5680A as a reference but now it is 
disconnected.
I have made a picture of the mod and I'll include it with my 
partial schematic (I made some advances there) and the list of the 
TP signals that I'm preparing for upload.
I have checked that now I have also 4 additional 1 PPS outputs in 
the 110 pin connector J2.  They are in the pins previously used by 
the SYS_CLK signal.  They are differential LVDS as most of the 
signals on this interface.


Regards,
Ignacio


El 13/06/2015 a las 1:14, Ed Armstrong escribió:
Ignacio, I would very much appreciate a copy of whatever 
schematics you have, even if it is not guaranteed to be 100% accurate


I agree with you that the 9.9804 Mhz is basically useless, while 
the even second pulse is merely almost useless. However, as you 
have apparently looked the board over more carefully than me, you 
probably already understand why I did it the way I did. The 
location of the two output circuits were very easy to find, the 
path from the connector to them is quite distinctive. I just 
needed to find out where the signal got into the output circuit 
from, and when I flipped the board over, the trace bringing in the 
even second pulse was extremely obvious. There was no obvious 
trace for the 9.9804, and I didn't feel like probing all over the 
place and looking up a lot of chip numbers to try to figure out 
where it came from, as I have a very unsteady hand which makes 
poking around in these closely spaced components an invitation to 
disaster. So I just went with the obvious.


I found it interesting that the output circuit inverts the signal 
a few times. I actually would have preferred to invert it, so that 
the polarity was correct

Re: [time-nuts] NTGS50AA 1 PPS mod

[EB4APL]

Hi,

I has been making some tests with the 1 PPS output and here are the results:

Lady Heather cable delay commands works with both polarities, i.e. it 
can advance or retard both 1/2 and 1 PPS signals, I used as reference 
and external 1 PPS signal from a Rb oscillator.
The first impression is that the 1 PPS  edge leads the 1/2 PPS about 550 
ns and this difference is consistent after some cable delay commands and 
antenna disconnections, it is maintained during holdover.
Then I tried several power cycling and warm resets and this make an 
annoying thing to appear: during the acquisition and phase locking the 
difference jumped between 540 and 140 ns in 100 ns steps.  This is due 
to the 1/2 PPS synchronization with the SYS_CLOCK signal, so when the 
internal 1/2 PPS moved back and forth until the system phase lock is 
obtained, the output jumps between successive cycles of the SYS_CLOCK.  
The annoying thing is that its final state is not always the same, the 
final difference can be any of the mentioned steps, from 120ns to 550 ns 
and there is not guarantee which one is obtained while in my board the 
540 ns difference is the most common.  I don't know yet  it the 1 PPS is 
closer to the epoch second or it is the 1/2 PPS, I have to hook up a 
GPS timing module and an antenna splitter and see what happens. Anyway 
since Nortel specifies a tolerance of +/- 1 us of the 1/2 PPS with 
respect to GPS even second, any of the seen values are within specs but 
it is not very convenient for Time Nuts.


Regards,
Ignacio

El 14/06/2015 a las 20:35, EB4APL wrote:
Even if I get a cell site I would not use it for a private network, 
here all cell phones are GSM not CDMA.
The only use for the 9.8304 MHz is as a master for deriving serial 
comm clocks (i.e. 9600 is  9.8304 / 1024) but I don't plan to became a 
Serial Comm Time Nut yet. ;-)


Ignacio


El 14/06/2015 a las 1:48, Bob Camp escribió:

Hi

Of course tomorrow you will stumble into a “great deal” on a complete 
cell site that needs a 9.8304 MHz clock :)




One thing to watch:

The pps you now have may or may not be deterministic in its relation 
to the every other second output. It also may or
may not be in a fixed relation to GPS. I would bet money that it *is* 
in a fixed relation and that it’s actually better than
the other signal. Just because I believe it to be true does not make 
it true. It needs to be checked against something else.


Bob



On Jun 13, 2015, at 1:56 PM, EB4APL eb4...@gmail.com wrote:

Hi,

I just finish the mod.  It was easy, I cut the trace between TP14 
and U405-6 and soldered a wire between TP14 and TP33. Now I have a 
pretty 1 PPS on J5, the old 9.8304 MHz output. The signal has 0-5 V 
levels, normally high with a 10 us pulse going down.  In my unit 
this pulse leads the even second pulse by 539 ns.  I will check if 
the Lady Heather command for compensating the cable length can be 
used to move this if somebody needs a more accurate epoch second. 
I have to use the 1PPS from my FE5680A as a reference but now it is 
disconnected.
I have made a picture of the mod and I'll include it with my partial 
schematic (I made some advances there) and the list of the TP 
signals that I'm preparing for upload.
I have checked that now I have also 4 additional 1 PPS outputs in 
the 110 pin connector J2.  They are in the pins previously used by 
the SYS_CLK signal.  They are differential LVDS as most of the 
signals on this interface.


Regards,
Ignacio


El 13/06/2015 a las 1:14, Ed Armstrong escribió:
Ignacio, I would very much appreciate a copy of whatever schematics 
you have, even if it is not guaranteed to be 100% accurate


I agree with you that the 9.9804 Mhz is basically useless, while 
the even second pulse is merely almost useless. However, as you 
have apparently looked the board over more carefully than me, you 
probably already understand why I did it the way I did. The 
location of the two output circuits were very easy to find, the 
path from the connector to them is quite distinctive. I just needed 
to find out where the signal got into the output circuit from, and 
when I flipped the board over, the trace bringing in the even 
second pulse was extremely obvious. There was no obvious trace for 
the 9.9804, and I didn't feel like probing all over the place and 
looking up a lot of chip numbers to try to figure out where it came 
from, as I have a very unsteady hand which makes poking around in 
these closely spaced components an invitation to disaster. So I 
just went with the obvious.


I found it interesting that the output circuit inverts the signal a 
few times. I actually would have preferred to invert it, so that 
the polarity was correct for a raspberry pie or a serial port under 
Windows, but it appeared some of the traces to do so were hidden in 
the layers of the board, and again the more I fool around the 
better my chance of shorting something out and becoming very unhappy.


I will be anxious to hear how your

Re: [time-nuts] NTGS50AA 1 PPS mod

[EB4APL]

Even if I get a cell site I would not use it for a private network, 
here all cell phones are GSM not CDMA.
The only use for the 9.8304 MHz is as a master for deriving serial comm 
clocks (i.e. 9600 is  9.8304 / 1024) but I don't plan to became a 
Serial Comm Time Nut yet. ;-)


Ignacio


El 14/06/2015 a las 1:48, Bob Camp escribió:

Hi

Of course tomorrow you will stumble into a “great deal” on a complete cell site 
that needs a 9.8304 MHz clock :)



One thing to watch:

The pps you now have may or may not be deterministic in its relation to the 
every other second output. It also may or
may not be in a fixed relation to GPS. I would bet money that it *is* in a 
fixed relation and that it’s actually better than
the other signal. Just because I believe it to be true does not make it true. 
It needs to be checked against something else.

Bob



On Jun 13, 2015, at 1:56 PM, EB4APL eb4...@gmail.com wrote:

Hi,

I just finish the mod.  It was easy, I cut the trace between TP14 and U405-6 and soldered 
a wire between TP14 and TP33.  Now I have a pretty 1 PPS on J5, the old 9.8304 MHz 
output.  The signal has 0-5 V levels, normally high with a 10 us pulse going down.  In my 
unit this pulse leads the even second pulse by 539 ns.  I will check if the Lady Heather 
command for compensating the cable length can be used to move this if somebody needs a 
more accurate epoch second. I have to use the 1PPS from my FE5680A as a 
reference but now it is disconnected.
I have made a picture of the mod and I'll include it with my partial schematic 
(I made some advances there) and the list of the TP signals that I'm preparing 
for upload.
I have checked that now I have also 4 additional 1 PPS outputs in the 110 pin 
connector J2.  They are in the pins previously used by the SYS_CLK signal.  
They are differential LVDS as most of the signals on this interface.

Regards,
Ignacio


El 13/06/2015 a las 1:14, Ed Armstrong escribió:

Ignacio, I would very much appreciate a copy of whatever schematics you have, 
even if it is not guaranteed to be 100% accurate

I agree with you that the 9.9804 Mhz is basically useless, while the even 
second pulse is merely almost useless. However, as you have apparently looked 
the board over more carefully than me, you probably already understand why I 
did it the way I did. The location of the two output circuits were very easy to 
find, the path from the connector to them is quite distinctive. I just needed 
to find out where the signal got into the output circuit from, and when I 
flipped the board over, the trace bringing in the even second pulse was 
extremely obvious. There was no obvious trace for the 9.9804, and I didn't feel 
like probing all over the place and looking up a lot of chip numbers to try to 
figure out where it came from, as I have a very unsteady hand which makes 
poking around in these closely spaced components an invitation to disaster. So 
I just went with the obvious.

I found it interesting that the output circuit inverts the signal a few times. 
I actually would have preferred to invert it, so that the polarity was correct 
for a raspberry pie or a serial port under Windows, but it appeared some of the 
traces to do so were hidden in the layers of the board, and again the more I 
fool around the better my chance of shorting something out and becoming very 
unhappy.

I will be anxious to hear how your version of the modification works out, 
please do keep us posted.

I believe the antenna cable feed delay is going to work in the wrong direction 
here, I also seem to recall reading somewhere that the adjustment range may be 
limited. I did pretty much correct the offset by manually setting my position 
about 75M higher than what the device figured it to be, but I am concerned that 
would only be accurate for a satellite directly overhead, and may cause other 
inaccuracies by throwing off the geometry, especially for satellites close to 
the horizon. Based on what I am currently seeing from the Pi, I think the smart 
solution is to just ignore the offset altogether.


Ed

On 6/10/2015 11:30 AM, EB4APL wrote:

Hi Ed,

I am the one who discovered the 1PPS pulse while troubleshooting a NTG550AA.  
Instead of reuse the 1/2 PPS output and missing this signal, my plan is to 
recycle the 9.8304 MHz output circuitry and connector, the circuits are almost 
identical.  So I will cut the trace that goes from TP14 to U405 pin 6 and also 
use a wire wrapping wire to joint TP14 to TP33 so the 1PPS will be at J5.  I 
think that I will do the modification this weekend.
I don't imagine any future use of the X8 Chip signal but having the even second 
output could be useful, at least to see the difference with the 1 PPS.
I had not measured the time difference yet, but I made a partial schematic of 
the board for my troubleshooting and there I see that the 1/2 PPS signal is 
synchronized with the 19.6608 signal that is the source for the 8X Chip ( 
9.8304 MHz), this is done in U405B

Re: [time-nuts] NTG550AA 1 PPS mod

[EB4APL]

Hi Ed,

While your board is not exactly the same as mine I think that the 
schematics are almost identical but the TPs and probably the chip names 
has changed.  I think that the main difference is that your unit can be 
powered with -48 V or +24 V and obviously the parts layout has changed.
I have made a partial schematic and it is a work in progress but it has 
been quite useful for me so far.  Since it was started when 
troubleshooting my board, I focused in certain areas and I still 
continue from time to time.  The troubleshooting effort, while some 
initial success, was not able to get good results and now I have a dead 
board that I can trace for expanding the schematic without much care .
I use Eagle to draw the schematic and I'm in the process of adding some 
chips to Eagle since they are not included in the standard library,  
when I finish I will add a new section which covers the signals that 
goes to and from the 110 pin connector J2.  I think it will be ready in 
a couple of days.
I plan to upload an Eagle .sch file and an image to Dropbox, I will 
inform you when it is ready.  The Eagle file could be useful for 
continuing the reverse engineering effort.
I'm working also in pictures of the board's top and bottom with the 
resistors and capacitors labeled according to the schematic, I 
registered the top with a mirror image of the bottom and this is a good 
way to find the correspondence of the vias but it is advancing at a 
slower pace, it takes a lot of time.  Also I have made a table with the 
signals of all the the test points, I will also include this.

I will keep you informed of the progress.
regarding the delay, I checked that Lady Heather accepts both positive 
and negative delays, in fact cable delays are considered negative.  I 
didn't checked that the board retards the pulses with positive values, 
I'll do it after the 1PPS mod but I think that this will work.  I 
believe that the elevation trick is not a good idea, it will ruin the 
GPS receiver calculations, as you say it will work for 1 satellite view 
and only when it is exactly overhead.


Best regards,
Ignacio


El 13/06/2015 a las 1:14, Ed Armstrong wrote:
Ignacio, I would very much appreciate a copy of whatever schematics 
you have, even if it is not guaranteed to be 100% accurate


I agree with you that the 9.9804 Mhz is basically useless, while the 
even second pulse is merely almost useless. However, as you have 
apparently looked the board over more carefully than me, you probably 
already understand why I did it the way I did. The location of the two 
output circuits were very easy to find, the path from the connector to 
them is quite distinctive. I just needed to find out where the signal 
got into the output circuit from, and when I flipped the board over, 
the trace bringing in the even second pulse was extremely obvious. 
There was no obvious trace for the 9.9804, and I didn't feel like 
probing all over the place and looking up a lot of chip numbers to try 
to figure out where it came from, as I have a very unsteady hand which 
makes poking around in these closely spaced components an invitation 
to disaster. So I just went with the obvious.


I found it interesting that the output circuit inverts the signal a 
few times. I actually would have preferred to invert it, so that the 
polarity was correct for a raspberry pie or a serial port under 
Windows, but it appeared some of the traces to do so were hidden in 
the layers of the board, and again the more I fool around the better 
my chance of shorting something out and becoming very unhappy.


I will be anxious to hear how your version of the modification works 
out, please do keep us posted.


I believe the antenna cable feed delay is going to work in the wrong 
direction here, I also seem to recall reading somewhere that the 
adjustment range may be limited. I did pretty much correct the offset 
by manually setting my position about 75M higher than what the device 
figured it to be, but I am concerned that would only be accurate for a 
satellite directly overhead, and may cause other inaccuracies by 
throwing off the geometry, especially for satellites close to the 
horizon. Based on what I am currently seeing from the Pi, I think the 
smart solution is to just ignore the offset altogether.



Ed

On 6/10/2015 11:30 AM, EB4APL wrote:

Hi Ed,

I am the one who discovered the 1PPS pulse while troubleshooting a 
NTG550AA.  Instead of reuse the 1/2 PPS output and missing this 
signal, my plan is to recycle the 9.8304 MHz output circuitry and 
connector, the circuits are almost identical.  So I will cut the 
trace that goes from TP14 to U405 pin 6 and also use a wire wrapping 
wire to joint TP14 to TP33 so the 1PPS will be at J5.  I think that I 
will do the modification this weekend.
I don't imagine any future use of the X8 Chip signal but having the 
even second output could be useful, at least to see the difference 
with the 1 PPS.
I had not measured the time

Re: [time-nuts] NTGS50AA 1 PPS mod

[EB4APL]

Hi,

I just finish the mod.  It was easy, I cut the trace between TP14 and 
U405-6 and soldered a wire between TP14 and TP33.  Now I have a pretty 1 
PPS on J5, the old 9.8304 MHz output.  The signal has 0-5 V levels, 
normally high with a 10 us pulse going down.  In my unit this pulse 
leads the even second pulse by 539 ns.  I will check if the Lady Heather 
command for compensating the cable length can be used to move this if 
somebody needs a more accurate epoch second. I have to use the 1PPS 
from my FE5680A as a reference but now it is disconnected.
I have made a picture of the mod and I'll include it with my partial 
schematic (I made some advances there) and the list of the TP signals 
that I'm preparing for upload.
I have checked that now I have also 4 additional 1 PPS outputs in the 
110 pin connector J2.  They are in the pins previously used by the 
SYS_CLK signal.  They are differential LVDS as most of the signals on 
this interface.


Regards,
Ignacio


El 13/06/2015 a las 1:14, Ed Armstrong escribió:
Ignacio, I would very much appreciate a copy of whatever schematics 
you have, even if it is not guaranteed to be 100% accurate


I agree with you that the 9.9804 Mhz is basically useless, while the 
even second pulse is merely almost useless. However, as you have 
apparently looked the board over more carefully than me, you probably 
already understand why I did it the way I did. The location of the two 
output circuits were very easy to find, the path from the connector to 
them is quite distinctive. I just needed to find out where the signal 
got into the output circuit from, and when I flipped the board over, 
the trace bringing in the even second pulse was extremely obvious. 
There was no obvious trace for the 9.9804, and I didn't feel like 
probing all over the place and looking up a lot of chip numbers to try 
to figure out where it came from, as I have a very unsteady hand which 
makes poking around in these closely spaced components an invitation 
to disaster. So I just went with the obvious.


I found it interesting that the output circuit inverts the signal a 
few times. I actually would have preferred to invert it, so that the 
polarity was correct for a raspberry pie or a serial port under 
Windows, but it appeared some of the traces to do so were hidden in 
the layers of the board, and again the more I fool around the better 
my chance of shorting something out and becoming very unhappy.


I will be anxious to hear how your version of the modification works 
out, please do keep us posted.


I believe the antenna cable feed delay is going to work in the wrong 
direction here, I also seem to recall reading somewhere that the 
adjustment range may be limited. I did pretty much correct the offset 
by manually setting my position about 75M higher than what the device 
figured it to be, but I am concerned that would only be accurate for a 
satellite directly overhead, and may cause other inaccuracies by 
throwing off the geometry, especially for satellites close to the 
horizon. Based on what I am currently seeing from the Pi, I think the 
smart solution is to just ignore the offset altogether.



Ed

On 6/10/2015 11:30 AM, EB4APL wrote:

Hi Ed,

I am the one who discovered the 1PPS pulse while troubleshooting a 
NTG550AA.  Instead of reuse the 1/2 PPS output and missing this 
signal, my plan is to recycle the 9.8304 MHz output circuitry and 
connector, the circuits are almost identical.  So I will cut the 
trace that goes from TP14 to U405 pin 6 and also use a wire wrapping 
wire to joint TP14 to TP33 so the 1PPS will be at J5.  I think that I 
will do the modification this weekend.
I don't imagine any future use of the X8 Chip signal but having the 
even second output could be useful, at least to see the difference 
with the 1 PPS.
I had not measured the time difference yet, but I made a partial 
schematic of the board for my troubleshooting and there I see that 
the 1/2 PPS signal is synchronized with the 19.6608 signal that is 
the source for the 8X Chip ( 9.8304 MHz), this is done in U405B . The 
period of this signal is about 50 ns and this is the origin of the 
1/2 PPS width.  The 19.6608 MHz oscillator is phase locked somewhere 
to the 10 MHz oscillator thus it is as stable as this one.
I think that using the other half of U405, which actually is used to 
divide by 2 the 19.6608 MHz signal, could render the 1 PPS 
synchronized with the 1/2 PPS and also with the same width. Probably 
the easier way to correct this is to use the command which sets the 
antenna cable delay and compensate for the difference.
I don't have a full schematic, even I am not sure that the partial 
one is 100% correct but I can send it to anyone who wants it.


Regards,
Ignacio




El 10/06/2015 a las 6:30, Ed Armstrong wrote:
Hi, this is my first post ever to a mailing list, so if I'm doing 
anything wrong please be gentle with your corrections :-)


A short time ago I purchased a Nortel/Trimble NTGS50AA

Re: [time-nuts] PPS for NTP Server - How Close Is Good Enough?

[EB4APL]

Hi Ed,

I have started another thread under the name NTG550AA 1 PPS mod for 
finding the subject easier and I include here my thoughts about this 
modification.


I am the one who discovered the 1PPS pulse while troubleshooting a 
NTG550AA.  For me I don't imagine any future use of the X8 Chip signal 
but having the even second output could be useful, at least to see the 
difference with the 1 PPS. Instead of removing the 1/2 PPS output and 
missing this signal, my plan is to recycle the 9.8304 MHz output 
circuitry and connector, the circuits are almost identical.  So I will 
cut the trace that goes from TP14 to U405 pin 6 and also use a wire to 
joint TP14 to TP33 so the 1PPS will be at J5.  I think that I will do 
the modification this weekend and will post the results and pictures.


I have not measured the time difference yet, but I made a partial 
schematic of the board for my troubleshooting and there I see that the 
1/2 PPS signal is synchronized with the 19.6608 signal that is the 
source for the 8X Chip ( 9.8304 MHz), this is done in U405B . The period 
of this signal is about 50 ns and this is the origin of the 1/2 PPS 
width.  The 19.6608 MHz oscillator is phase locked somewhere to the 10 
MHz oscillator thus it is as stable as this one.


I think that using the other half of U405, which actually is used to 
divide by 2 the 19.6608 MHz signal, could render the 1 PPS synchronized 
with the 1/2 PPS and also with the same width but probably  this is 
overkill and an easier way to adjust this is to use the command which 
sets the antenna cable delay and compensate for the difference.


Checking the specs documentation of a very close cousin of this board, 
the GSBW50AA, I found the requirement for the even second pulse: +/-1 
μs traceable to and synchronous with GPS Time Even_Second with at least 
one satellite in view.  In fact this is something not easy to measure 
unless you have a calibrated 1 PPS source.
Another spec states  The falling edge of Even_Second shall occur 0-5 ns 
after the falling edge of SYS_CLK. (the 9.8304 MHz signal that is used 
as the clock reference in the CDMA system).
This specs are the reason why the even second pulse is synchronized to 
the SYS_CLK as I said before.


So my opinion is that the difference that you measured is not relevant 
because we can not be sure about the even second accuracy and if we need 
to be sure of  the absolute time we will need to compare the 1 PPS 
output against a calibrated source, maybe another GPSDO that has been 
compared with a known standard and compensated for the antenna cable 
delay.  Of course for a NTP server you have more than enough.


As I said in the other post I have a partial schematic of the board, ask 
me if you want a copy.

Best regards,
Ignacio


El 10/06/2015 a las 6:30, Ed Armstrong wrote:
Hi, this is my first post ever to a mailing list, so if I'm doing 
anything wrong please be gentle with your corrections :-)


A short time ago I purchased a Nortel/Trimble NTGS50AA GPSTM, I'm sure 
many on this list are familiar with it. At the time of purchase, my 
only interest was the 10 MHz output, for use with my HP5328b frequency 
counter and perhaps in the future also my signal generator. No 
question here, it just works great as is. However, it certainly seems 
best to leave these devices powered up all the time.


OK, now were getting close to my question. The unit pulls about 10-11 
watts, which is really not very much. But it kinda bugs me to have it 
sit there using electric and basically doing nothing when I'm not 
using it. So, I bought a Raspberry Pi 2 with the intent of using it as 
an NTP server. I can't really say I'm enjoying my intro to Linux a 
whole lot, but I'll get there. It still needs some work, but it does 
function with the PPS output from an Adafruit ultimate GPS, which I 
bought for testing this and possibly building my own GPSDO in the future.


The NTGS50AA is a very capable device, but unfortunately it does not 
have a PPS output. Instead it has an even second output, which goes 
low for approximately 50 ns. The falling edge of this pulse marks the 
beginning of the second. During my search for a solution to this, I 
came across a post from this mailing list which I believe was 
discussing repair of one of these units. Someone in that post 
mentioned that there was a PPS signal at test point 33 which went low 
for about 10 µs. Thank you, that saves me a lot of probing.


The first thing I did was verify that this pulse did exist, then I 
decided to examine it a little closer. I kind of suspected that it may 
have been a rather raw pulse as received from the satellites. I found 
out that is not correct, once the unit successfully phase locks, this 
PPS signal is very accurately tied to the 10 MHz output, even when the 
unit goes into holdover mode. I was very happy about this :-) Next 
step was to see how accurately it was synced to the even second pulse. 
The bad news is that it does not occur 

[time-nuts] NTG550AA 1 PPS mod

[EB4APL]

Hi Ed,

I am the one who discovered the 1PPS pulse while troubleshooting a 
NTG550AA.  Instead of reuse the 1/2 PPS output and missing this signal, 
my plan is to recycle the 9.8304 MHz output circuitry and connector, the 
circuits are almost identical.  So I will cut the trace that goes from 
TP14 to U405 pin 6 and also use a wire wrapping wire to joint TP14 to 
TP33 so the 1PPS will be at J5.  I think that I will do the modification 
this weekend.
I don't imagine any future use of the X8 Chip signal but having the even 
second output could be useful, at least to see the difference with the 1 
PPS.
I had not measured the time difference yet, but I made a partial 
schematic of the board for my troubleshooting and there I see that the 
1/2 PPS signal is synchronized with the 19.6608 signal that is the 
source for the 8X Chip ( 9.8304 MHz), this is done in U405B . The period 
of this signal is about 50 ns and this is the origin of the 1/2 PPS 
width.  The 19.6608 MHz oscillator is phase locked somewhere to the 10 
MHz oscillator thus it is as stable as this one.
I think that using the other half of U405, which actually is used to 
divide by 2 the 19.6608 MHz signal, could render the 1 PPS synchronized 
with the 1/2 PPS and also with the same width. Probably the easier way 
to correct this is to use the command which sets the antenna cable delay 
and compensate for the difference.
I don't have a full schematic, even I am not sure that the partial one 
is 100% correct but I can send it to anyone who wants it.


Regards,
Ignacio




El 10/06/2015 a las 6:30, Ed Armstrong wrote:
Hi, this is my first post ever to a mailing list, so if I'm doing 
anything wrong please be gentle with your corrections :-)


A short time ago I purchased a Nortel/Trimble NTGS50AA GPSTM, I'm sure 
many on this list are familiar with it. At the time of purchase, my 
only interest was the 10 MHz output, for use with my HP5328b frequency 
counter and perhaps in the future also my signal generator. No 
question here, it just works great as is. However, it certainly seems 
best to leave these devices powered up all the time.


OK, now were getting close to my question. The unit pulls about 10-11 
watts, which is really not very much. But it kinda bugs me to have it 
sit there using electric and basically doing nothing when I'm not 
using it. So, I bought a Raspberry Pi 2 with the intent of using it as 
an NTP server. I can't really say I'm enjoying my intro to Linux a 
whole lot, but I'll get there. It still needs some work, but it does 
function with the PPS output from an Adafruit ultimate GPS, which I 
bought for testing this and possibly building my own GPSDO in the future.


The NTGS50AA is a very capable device, but unfortunately it does not 
have a PPS output. Instead it has an even second output, which goes 
low for approximately 50 ns. The falling edge of this pulse marks the 
beginning of the second. During my search for a solution to this, I 
came across a post from this mailing list which I believe was 
discussing repair of one of these units. Someone in that post 
mentioned that there was a PPS signal at test point 33 which went low 
for about 10 µs. Thank you, that saves me a lot of probing.


The first thing I did was verify that this pulse did exist, then I 
decided to examine it a little closer. I kind of suspected that it may 
have been a rather raw pulse as received from the satellites. I found 
out that is not correct, once the unit successfully phase locks, this 
PPS signal is very accurately tied to the 10 MHz output, even when the 
unit goes into holdover mode. I was very happy about this :-) Next 
step was to see how accurately it was synced to the even second pulse. 
The bad news is that it does not occur at exactly the same time as the 
even second. The good news is that the offset is very consistent, 253 
ns before the even second pulse, +/- 1 ns.


My next step was to find out where the even second pulse entered the 
output circuitry. I then broke the trace taking the even second into 
the output circuitry, and ran a piece of 30gauge wire wrapping wire 
from the via at test point 33 to the via at the input to the output 
circuitry. The wire fit so perfectly it felt like the vias were made 
for just this purpose :-) Now I've got a very nice PPS signal 
available both at the front jack and at the backplane connector in the 
rear of the unit.


OK, here is the actual question. Do you think it is OK to consider a 
pulse which arise 250 ns early to be close enough? And no, I am not 
forgetting about that 3 ns, there is about 3 ns of delay added by the 
output circuitry.


Hope you didn't mind the long-winded post, and I thank you in advance 
for any advice you offer.



Ed



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Re: [time-nuts] pp2s? No, 1pps from a Nortel GPSTM!

[EB4APL]

Hi,

I have another Thunderbolt cousin, a NTGS50AA.  For a long time I 
desired to have 1PPS from it and even I asked this list for a cue, the 
responses were negative, some thought that there were no 1PPS outside 
the big chips.
My unit developed a problem and troubleshooting it I found the wanted 1 
PPS at TP-33 coming from U2-76.  Given that this GPSDO has two outputs 
whose usefulness is dubious, 1/2 PPS and 9.8304 MHz (we don't have a 
CDMA tower, do we?), my plan is to use one of these outputs for the 1PPS 
signal.  Both outputs have drivers that are identical so probably I will 
cut the 9.83404 signal just before the driver and solder a piece of wire 
wrapping wire from TP-33 to the driver input.  In that way I will have 
1/2 PPS and 1 PPS on the output connectors.
I have checked that the 1PPS is totally synchronous with the 1/2 PPS, I 
don't have means of properly check the jitter between both signals but a 
scope shows no jitter at all.
The above mentioned problem became worse and finally I had to replace 
the whole thing.  Fortunately a member of this list kindly offered to 
sell me one of this spare units and now my reference is working fine.  
As soon I have a time gap I'll do the modification and publish the pictures.


Regards,
Ignacio


El 26/05/2015 a las 14:09, Tom Van Baak wrote:

Hi Nate,

Nice page. Thanks for sharing your work.

The Nortel units are a reasonable and slightly cheaper alternative to a TBolt, 
if you don't mind the much larger size, mass, and non-standard connector issues.
The performance depends somewhat on which vendor's oscillator was used. I 
tested a bunch here:
http://www.leapsecond.com/pages/nortel/
For NTP none of these plots matter (most GPSDO are a thousand to a million 
times more stable than NTP or a PC can handle).

/tvb

- Original Message -
From: Nathaniel Bezanson mys...@telcodata.us
To: time-nuts@febo.com
Sent: Monday, May 25, 2015 7:08 PM
Subject: [time-nuts] pp2s? No, 1pps from a Nortel GPSTM!



As anyone with a Nortel GPSTM knows, it's a close cousin to the Thunderbolt but not 
exactly identical. Notably, coming from a CDMA environment, the unit has an even 
second output, aka PP2S, aka 0.5pps, aka 0.5Hz, etc. (Hoping to make this 
searchable...) There are software commands to configure this on the Thunderbolt too, but 
the GPSTM appears to have this function hard-coded into the PAL, and it can't be set back 
to PPS in software.
However, there exists a PPS signal on the PCB, at TP13 between the Trimble chip 
and the PAL, discovered by some folks at the hackerspace here, during some 
noodling-around with an oscilloscope this afternoon. It's all documented here:
https://www.i3detroit.org/wiki/Nortel_GPSTM
This is for a NTBW50AA-11 module (single long board), other parts may have the 
signal in different places but I bet it's in there.
Enjoy!-Nate B-

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Re: [time-nuts] 00105-6013 schematic wanted

[EB4APL]

Hi Luciano,

The full  schematics are in the HP5061 manual, including theory of 
operation.  I can extract  the pages and send them to you.  I also 
checked in the 5065 manual but it only includes the block diagram with 
warnings against field repair / adjust or your warranty will be void :)  .


Regards,
Ignacio EB4APL


El 05/02/2015 a las 15:10, tim...@timeok.it escribió:



Hi all,

I am looking for the internal schematic of the 00105-6013 OCXO mounted in the 
old series of the HP5065A.
I have two of them not working and I would like to fix it.

thanks,

Luciano
www.timeok.it
Message sent via Atmail Open - http://atmail.org/
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Re: [time-nuts] HP-58503A

[EB4APL]

Hi,

The past week I had to replace more than 30 capacitors in various of my 
home electronics, some were bulged and others not so.
There were 7 in a computer motherboard, 10 in other, 8 in a TV set power 
supply, 2 in an external USB disk power supply and the rest in other 
things, I know the grand total because I kept it together to test a 
cheap EMS meter against a LCR bridge.
In my experience, all bulged capacitors are very ill, high ESR and very 
low capacitance, causing a lot of symptoms to appear (many of them 
intermittent).  And when a capacitor bulges normally some or all of its 
neighbors are bad also, even without any external sign. I check them 
with a bridge and this is confirmed most of the times, so I suggest to 
replace the bulged capacitor and when you are there check or replace the 
others, they will bulge or burst in short time, high ripple currents and 
heat makes electrolytics the less reliable electronic components today.


Best regards,
Ignacio EB4APL


On 02/01/2015 a las 14:34, Dr. David Kirkby (Kirkby Microwave Ltd) wrote:

On 1 January 2015 at 17:03, Andy Bardagjy andybarda...@gmail.com wrote:

Sounds like the GPS receiver is hosed. I think there are two different 
receivers used in the 58503a, unfortunately I'm away from my lab, otherwise I 
could check mine. It is a standard part, and may be available on the surplus 
market.

Before replacing, I'd check the usual suspects, power supply health (look for 
failed electrolytics) and re-seat the gps board to board connector.

Happy to measure things on my 58503a.

The fact it originally failed with errors indicting the GPS receiver
was not ok (nt Power- OK, OCXO- OK, EFC-OK GPS RCV-err. I, but later
he can't communicate with the 58503A over RS-232, to me indicates the
problem is not likely to be the just (if at all) the GPS receiver.

As you say, power supply is a possible problem.

I have a 58503A here that has a problem. Sometimes when power is first
applied, the Alarm light stays on, and the log show power supply
voltage errors. Yesterday I must have switched the thing on/off about
30 times before I managed to get the Alarm light to stay on. At the
time I had a handheld DVM connected to the +15 V rail with the peak
hold mode enabled. At least according to the handheld DVM, the +15 V
rail was normal, so either the transient is too short for my handheld
DVM to see, or the 85050A is reporting data voltage data incorrectly.
Both are fairly like I suspect.

I noticed a *very* slight bulge at the top of on a 100 uF, 400 V
capacitor on the switch mode power supply.  For various reasons, I am
not going to change that cap now, but obviously a failed cap could
cause this sort of problem.

Dave



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Re: [time-nuts] 1900kHz radiolcation testing on east coast US?

[EB4APL]

Taking in account that is is heard quite strong in most US and even in 
Toronto and that it sweeps in a fairly controlled way it is an 
intentional radiator.  It could be an ionospheric sounder or a sea waves 
measuring device of a new kind. I think that an interference so powerful 
must be discarded.
I don't receive it in Spain but I'm very close to several powerful MW 
broadcast transmitters and they can mask the signal due to saturation.


Ignacio EB4APL

On 08/12/2014 a las 2:41, Chuck Harris wrote:

Hi Tim,

Look for a switching power supply that is fairly new, and is
of the sort that doesn't need to be messed with to cover the full
120V to 240V range.

That sort of switcher is also known as a power factor correcting
switcher.  It has a PWM switched pre-regulator that takes the
unfiltered ripple straight from a full wave bridge rectifier, and
PWM's it so that it can charge the filter capacitor, without the
power line seeing anything but a resistive load.  It also controls
the inrush current.

PWM pre filters, because they quickly shift the pwm signal at a
120Hz rate, are capable of producing lots of broadband 120Hz
modulated garbage if their shields, or filters are compromised.

-Chuck Harris

Tim Shoppa wrote:

Would any time-nuts know of radiolocation-type testing going on, on east
coast of US, maybe around Maine? There is a very strong wideband 
signal on
1900-1920kHz, with a 120Hz substructure and a 4Hz rep-rate, likely 
megawatt

power range.

Sound sample (recorded with 2400Hz receiver bandwidth, although the 
whole

signal is far far wider bandwidth) at
http://www.trailing-edge.com/1910-intruder.wav

Pics of the waveform at 
http://www.trailing-edge.com/1910-intruder-1.png and

zoomed in at http://www.trailing-edge.com/1910-intruder-2.png

Tim N3QE
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[time-nuts] Test, delete

[EB4APL]

This is only for testing  my new email address. Don't answer.
Sorry for the BW.
Ignacio
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Re: [time-nuts] LTE-Lite

[EB4APL]

Hi,

Just a word of caution here:
Do not trust Google Earth data for any precision work. The mentioned six 
feet are probably due to the geographical data, not to the precission 
of  your GPS unit.  If you look for image seams you can verify the kind 
of errors involved.
Google Earth is not a professional data source, if you want to use it 
por precise work they offer the option to load your own maps and images 
for your use , but this is not a free service.  The free service and 
data is good for showing your favorite pub to your friends.


Regards.
Ignacio EB4APL

On 30/11/2014 a las 19:23, Jim Sanford wrote:

SO, I just connected my third LTE-Lite unit.
By the time the software drivers were installed, and I selected 
U-center to the new COMM port, it had a fix.  Even with the survey LED 
still blinking.


I looked at the GoogleEarth view, and the fix is within six feet of 
where the antenna really is.  IMPRESSIVE.


BTW, the 10 MHz unit I ran for a couple of days showed a fix on 
GoogleEarth within less than a foot of the antenna location.

Most impressive.

Jim

On 11/28/2014 4:23 PM, Jim Sanford wrote:

All:

After running my 20 MHz LTE-Lite for a week or so, I shut it down and 
connected one of the 10 MHz units.


The LEDs appear to be responding (survey still in progress) as per 
the quick start guide.


Windows installed a new comm port and driver.  (COMM6, with FTDI 
driver)  The COMM5 port which was the 20 MHz unit is gone.


U-center has selected COMM6 and is autobaud at 38000, but is showing 
my nothing except blank screens and a red NO FIX.  Have I missed 
something?  Or will it not report anything until a lock is achieved??


Thanks,
Jim
wb4...@amsat.org




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Re: [time-nuts] LTE-Lite

[EB4APL]

On 30/11/2014 a las 22:49, Hal Murray wrote:

eb4...@cembreros.jazztel.es said:

Do not trust Google Earth data for any precision work. The mentioned six
feet are probably due to the geographical data, not to the precission  of
your GPS unit.  If you look for image seams you can verify the kind  of
errors involved.

How good are USGS topo maps for this sort of thing?  Most streets are shown
as a pair of parallel lines, but the separation of the lines doesn't match
the actual width of most streets.  Does the center of that pair on the paper
correspond to the center of the road?  Can I use the intersection of a pair
of streets as a reference point?  ...

How about equivalent maps for other countries?

How well do typical benchmarks agree with GPS?

Are the surveyors maps used for deeds useful in this context?
In fact I'm not familiar with USGS topo maps, but here in Spain for the 
small scales(Scale 1:25000 and lower) the streets and roads are not wide 
enough to be accurately represented, so a symbol is used instead.  The 
symbol style is selected to mean the type of road and yes, the center of 
the parallel lines corresponds to the center of the street.  Another 
thing is the overall precision, here it is established that the 
precision of the paper maps should be equal to the unaided eye 
resolution, about 1/4 mm, so you multiply .25 mm times the scale 
denominator and you get the precision. Our main national topographic map 
is at 1:25000 scale and its precision is about 6.25 meters.  For digital 
maps the precision is what the map provider says, since a digital map 
can be enlarged at will. Usually the precision is consistent with the 
intended representation scale in the same terms as the paper maps.


Since Google's geographical data is usually obtained from official 
sources, the line maps are quite good, but the satellite images usually 
are not very well rectified and stitched, unless they are obtained from 
similar sources which put a lot of effort on its accuracy and matching 
with the maps.  This varies a lot depending the region.


The surveyor maps usually agree very well with GPS, in fact they are 
based in GPS measured reference points these days.


This comes from my limited experience, the results can be very different 
depending the zone and the date.


Best regards,
Ignacio EB4APL

  

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Re: [time-nuts] My NTGS50AA failed

[EB4APL]

Hi,

In my case, if the problem is the op-amp or some passive around, it can 
be easily replaced.  If not the only solution is to find a parts unit to 
transplant the programmed Xilinx chip.  Now I'm quite busy trying to get 
the schematic of the op-amp zone.


Regards,
Ignacio



El 14/11/2014 a las 13:32, Bob Camp escribió:

Hi

I have a Bolt that has a similar stuck EFC. In my case it’s not the OCXO 
either. There is some sort of failure on the inputs to the summing op amp that 
drives the output to the high end of the DAC’s range.

Bob


On Nov 13, 2014, at 9:06 PM, EB4APL eb4...@cembreros.jazztel.es wrote:

Hello Nigel,

Finally I got enough courage and removed the OCXO, you know what kind of task 
it is..  Fortunately I didn't spoiled the PCB so I'll install 2 smb connectors 
in the provided places, I don't want to return there if I need to change the 
oscillator.
Well, the oscillator is ok, this is in some way bad news because the oscillator 
is easily replaceable, and the EFC voltage remains stuck on 5.02 V.  Now I'll 
test the quad op-amp and the related parts.  If they are ok the problem is in 
the Xilinx chip, something that cannot be replaced unless I get  parts donor, 
even that way is very problematic since it is a  80 pin chip.  I'll continue 
posting my findings.

Best regards,
Ignacio


El 13/11/2014 a las 12:03, GandalfG8--- via time-nuts escribió:

Hi Ignacio
  I'm sure removing the oscillator would make your faultfinding much more
straightforward.
  When I removed mine I started out quite convinced I wouldn't be able to do
it, even with the solder mostly removed from around the pins they were
obviously  quite a tight fit and all I had available at that time was a plunger
type  solder sucker and desoldering braid, as the bits on my old Pace
desoldering kit  were well past their best.
The answer basically was lots of braid, lots of patience, and resisting
like crazy any temptation to pull against a hole that wasn't fully released,
but  I certainly wouldn't want to do it that way again in a hurry.
The desoldering gun I use now would make it easier but the holes are really
  a bit small for those oscillator pins.
  The good news though is that the connectors are there as a back up and
fitting them definitely makes it more versatile.
I had considered repeating the performance on another NTGS50AA  and/or
NTBW50AA, I really think I should but so far haven't found the  courage:-)
  I think previous checks for 1PPS outputs might have been limited to the
external connectors but it would make sense if it was available somewhere on
the  PCB, I'll try to get one powered up later and check your findings, if I
can find  a bit of space that us amongst the usual chaos!
  Regards
  Nigel
GM8PZR
In a message dated 13/11/2014 01:11:30 GMT Standard Time,
eb4...@cembreros.jazztel.es writes:

Hi  Nigel,

Thank you for the suggestions, I was trying to avoid the OCXO  removal but
I think that now it must be done.
I was also playing with the  idea of populating the connectors so an OCXO
exchange could be easily made,  this makes possible to try various
oscillators.
Meanwhile I has been  probing and measuring a lot of points and by chance I
found a very interesting  thing:  Probing TP33 (which is close to the
Trimble chip (U2) and  directly connected to pin 76) there is a 1PPS, 10 us wide
signal.  I've  checked it and appears to be synchronous with the 1/2 PPS
output so maybe it  can be routed to an output, probably I'll replace the 1/2
PPS with it, using  the existing drive circuit and connector since it is very
  straightforward.
My only concern is if this signal only is there during the  anomalous
condition that I have now, I have to retest it after fixing it.
I  had asked several times if anybody had located a 1PPS signal on these
units,  but the responses were negative and I had not probed systematically
the board  before.  Also I'm taking notes of the signals found and I'll try to
make  a partial schematic at least with the EFC circuitry.  When I fix it
I'll  clean the notes and figures and I'll upload it to some place.


Best  regards,
Ignacio

El 12/11/2014 a las 11:47, GandalfG8--- via  time-nuts escribió:

Hi Ignacio

  
I have removed a faulty oscillator from one of these, not one  of my more


relaxed moments and quite amazed when the board emerged totally  undamaged,

but proof at least that it can be done:-)

  
With the oscillator removed there's access to two sets of connector  pads


that will either accept SMA or SMB connectors and after  conducting tests
on

the original oscillator via flying leads just  soldered to the board I

decided not to fit a replacement to the board after  all but to fit a
couple of

SMB connectors to make the setup more versatile, and  to avoid the

possibility of having to remove another oscillator in the  future:-)

Another advantage of these pads is that if the board does get damaged

removing the oscillator they can still be used as an alternative

Re: [time-nuts] My NTGS50AA failed

[EB4APL]

 of the NTGS50AA should be 6 volts, not 5 as

you're seeing, and another indication it might be worth removing the

oscillator  to see how the board behaves stand alone.

I've not seen what seemed to be the repeated attempts at lock that you

mentioned previously, but then I wasn't even aware for a long time that the
  


control voltage could drive below 3 volts as well as above it:-)

  


This is my note from previous observation of my faulty  unit

  


-

When first powered it brings up all LEDs and then switches to a green LED

for a few seconds and then amber. It starts a self survey and acquisition

process with all appearing ok, and the DAC voltage reported as 3.02

volts.

Sometime later, I've seen as short as 6 minutes but as long as 12 to  15

depending on how long the oscillator has been turned off and allowed to
cool,

once enough satellites are being tracked, the DAC voltage starts to

increase,  presumably seeking to drive the oscillator frequency to 10MHz,
but the

frequency  doesn't reach 10MHz and the DAC voltage ramps up to 6.04
volts

over a period  of approx 30 seconds where it remains.

As the DAC voltage crosses approx 5.6  volts the Red fault LED is

switched on, as opposed to green that would  normally be expected to
indicate all

was well, and Lady Heather's OSC: report  switches from Good to Bad and

highlights red. Similarly Normal OSC age changes  to OSC age alarm and
also

highlights red.

---

  


I've attached a Lady H plot that shows this, hopefully it will get through

OK.

  


The above DAC voltages were as reported by Lady Heather but I've checked

these and, when the board is working as it should be anyway,  they're very

close.

  


In my case the problem described above was an oscillator that had  aged

beyond the upper 6 volt limit, needing approx 6.54 volts to reach  10MHz,
and

once removed from the board I was able to add a simple op  amp level
shifter

to bring it back into range just to prove all else was ok,  which it was,

but obviously Lady H now indicated the EFC into the level  shifter rather
than

at the oscillator itself.

  


Whilst your problem sounds like it might not be quite such an obvious  fix,

removing the oscillator would open the loop and make  testing both the

oscillator and the board much easier, so much as it's  a pain I do feel
that's

probably your best next step.

  


Regards

  


Nigel

GM8PZR

  

  

  

  

  

  


In a message dated 12/11/2014 02:06:54 GMT Standard Time,

_eb4apl@cembreros.jazztel.es_ (mailto:eb4...@cembreros.jazztel.es)  writes:



Hi,



Removing the oscillator for testing and replacing it  with other if it

was the culprit was my first option.  I have a spare  Trimble oscillator

that probably came from other NTGS50AA since it still  have the foam band

attached, but this oscillator is really aged, it needs  7.91 V to bring

it on spot and the maximum control voltage of the NTGS50AA  is 5 V.

I was trying to avoid removing the oscillator but probably it must  be

done to clarify things.



Thank you,

Ignacio  EB4APL



.

El 12/11/2014 a las 2:40, Mark Sims escribió:


I  have seen this caused by the oscillator not responding to the EFC


signal.  Fixed it by swapping in a MV-89 oscillator.


The  oscillators used in these units don't output an oven temperature


monitor  signal.


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Re: [time-nuts] My NTGS50AA failed

[EB4APL]

Charles,

Thank you, I found this very enlightening.  Now I have to find the 9.7 
KHz pulses, no luck so far.


Best regards,
Ignacio


El 12/11/2014 a las 7:34, Charles Steinmetz escribió:

Ignacio wrote:

I'm not very sure that the DAC is working, I suppose that the unit 
doesn't measure the DAC output, it reports the DAC commands.  My 
voltage figures is what LH reports (so the NTGS50AA reports, probably 
what it is trying to do), but the frequency control pin of the 
oscillator is stuck at 5.02 V regardless of the supposed (intended) 
DAC output, it does not move at all.


One more thing that could be helpful -- on Nov. 2, 2013 Stewart Cobb 
posted a description of the DAC operation for a Trimble Thunderbolt 
(Thunderbolt tuning DAC theory of operation).  On Jan. 5, 2014 
someone (no name) posted further information on the same thread re: 
the Trimble/Nortel 45k.  You can find both posts in the list archives 
(follow the link at the bottom of this post, then click time-nuts 
Archives on the list home page).


Best regards,

Charles



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Re: [time-nuts] My NTGS50AA failed

[EB4APL]

  fix,

removing the oscillator would open the loop and make  testing both the
oscillator and the board much easier, so much as it's  a pain I do feel that's
probably your best next step.
  
Regards
  
Nigel

GM8PZR
  
  
  
  
  
  
In a message dated 12/11/2014 02:06:54 GMT Standard Time,

eb4...@cembreros.jazztel.es writes:

Hi,

Removing the oscillator for testing and replacing it  with other if it
was the culprit was my first option.  I have a spare  Trimble oscillator
that probably came from other NTGS50AA since it still  have the foam band
attached, but this oscillator is really aged, it needs  7.91 V to bring
it on spot and the maximum control voltage of the NTGS50AA  is 5 V.
I was trying to avoid removing the oscillator but probably it must  be
done to clarify things.

Thank you,
Ignacio  EB4APL

.
El 12/11/2014 a las 2:40, Mark Sims escribió:

I  have seen this caused by the oscillator not responding to the EFC

signal.  Fixed it by swapping in a MV-89 oscillator.

The  oscillators used in these units don't output an oven temperature

monitor  signal.

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[time-nuts] My NTGS50AA failed

[EB4APL]

Hello,

After 2 yeses of continuous operation my NTGS50AA turned its red led on 
and stopped working. A check with LH shows OSC: BAD and OSC age 
alarm assuming that the oscillator had aged too much.
I didn't believe this because when working, the DAC control voltage was 
around 2.9 V, in fact near the middle of its range (0-5 V). Measuring 
the 10 MHz output it is high, about 4.46 Hz which agrees with the LH 
figures.
I measured the oscillator EFC pin and it is struck at 5.02 V, not 
following the DAC voltages as reported by LH. I think that either the 
DAC is bad or an amplifier after it.  Since I don't have any schematic 
and the oscillator covers the top layer the troubleshooting is difficult.
Has anybody experienced this failure before?.  Does anybody has an 
schematic, even a partial one?


Since the unit now is operating open loop I observed the locking 
strategy of this GPSDO.  First it waits about 12 minutes for warming (I 
don't know if it internally monitors the oven current or uses a fixed 
time).  During this period it sets the DAC output to the initial value 
as stored in the EEPROM (3.0 V).
When it thinks that it is warmed enough, the DAC is ramped in the 
right direction to intercept exactly 10 MHz (towards 0 in my case). If 
it reaches 0 then declares the alarm and the DAC voltage is set to half 
the initial value (1.5 V). Five minutes later it switch the DAC to 2,25 
V and 17 seconds later it returns to 1.5 V and remains there for 4 min 
and a half.  Then it goes up again to 2.5 V and after 10 seconds it goes 
down to 1.88 V and after some 14 minutes it goes down again to 1.5 V, it 
remains there for about 15 minutes and then it goes down to 1.14 V, 
remains there for 80 seconds and goes back to 2.5 V.
It looks like it checks from time to time if it is able to control the 
oscillator or simply it does weird things once it thinks that the 
oscillator cannot be disciplined.


I will appreciate very much any information.that can help my 
troubleshooting.  These units has more than doubled its price since I 
bought mine and I think that they are vanishing.  The Guatemala's cell 
towers scrap has been exhausted.


Regards,
Ignacio EB4APL







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Re: [time-nuts] My NTGS50AA failed

[EB4APL]

Hi,
I meant 2 years, it is quite late here.
I'm not very sure that the DAC is working, I suppose that the unit 
doesn't measure the DAC output, it reports the DAC commands.  My voltage 
figures is what LH reports (so the NTGS50AA reports, probably what it is 
trying to do), but the frequency control pin of the oscillator is stuck 
at 5.02 V regardless of the supposed (intended) DAC output, it does not 
move at all.
I have checked the internal power supply voltages and they are ok. 
Hopefully a capacitor could be shorted to the +5V line but it looks too 
much luck for me.


Thank you for your suggestions,
Ignacio EB4APL


On 12/11/2014 a las 2:23, Bob Camp wrote:

Hi

Ok, the gizmo you have is pretty similar to a Thunderbolt in terms of what they 
did for circuits. It’s by no means identical and I have not traced either one 
out far enough to have a schematic.

At least from the TBolt - your DAC is working. The voltage is moving around and 
it’s getting low enough to bring the oscillator into lock. That suggests that 
the problem is not the DAC it’s self. I’d bet that what ever magic they do to 
figure out the oscillator frequency has gone nuts.  A very common approach is 
to use the GPS PPS like a gate on a frequency counter. I think that this part 
gets a bit more fancy than that. Either way, that sounds like where the problem 
lies.

Just in case - always check the regulated power supply voltages on the board 
and touch test the bypass caps. It’s a silly thing, but it doesn’t take long to 
do. I know I have gone for a few hours / days / weeks on something like this, 
only to finally bump into the shorted bypass cap or dead regulator and go 
“h…..”.

Bob



On Nov 11, 2014, at 8:07 PM, EB4APL eb4...@cembreros.jazztel.es wrote:

Hello,

After 2 yeses of continuous operation my NTGS50AA turned its red led on and stopped working. A 
check with LH shows OSC: BAD and OSC age alarm assuming that the oscillator 
had aged too much.
I didn't believe this because when working, the DAC control voltage was around 
2.9 V, in fact near the middle of its range (0-5 V). Measuring the 10 MHz 
output it is high, about 4.46 Hz which agrees with the LH figures.
I measured the oscillator EFC pin and it is struck at 5.02 V, not following the 
DAC voltages as reported by LH. I think that either the DAC is bad or an 
amplifier after it.  Since I don't have any schematic and the oscillator covers 
the top layer the troubleshooting is difficult.
Has anybody experienced this failure before?.  Does anybody has an schematic, 
even a partial one?

Since the unit now is operating open loop I observed the locking strategy of 
this GPSDO.  First it waits about 12 minutes for warming (I don't know if it 
internally monitors the oven current or uses a fixed time).  During this period 
it sets the DAC output to the initial value as stored in the EEPROM (3.0 V).
When it thinks that it is warmed enough, the DAC is ramped in the right 
direction to intercept exactly 10 MHz (towards 0 in my case). If it reaches 0 then 
declares the alarm and the DAC voltage is set to half the initial value (1.5 V). Five 
minutes later it switch the DAC to 2,25 V and 17 seconds later it returns to 1.5 V and 
remains there for 4 min and a half.  Then it goes up again to 2.5 V and after 10 seconds 
it goes down to 1.88 V and after some 14 minutes it goes down again to 1.5 V, it remains 
there for about 15 minutes and then it goes down to 1.14 V, remains there for 80 seconds 
and goes back to 2.5 V.
It looks like it checks from time to time if it is able to control the 
oscillator or simply it does weird things once it thinks that the oscillator 
cannot be disciplined.

I will appreciate very much any information.that can help my troubleshooting.  
These units has more than doubled its price since I bought mine and I think 
that they are vanishing.  The Guatemala's cell towers scrap has been exhausted.

Regards,
Ignacio EB4APL







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Re: [time-nuts] My NTGS50AA failed

[EB4APL]

Hi,

Removing the oscillator for testing and replacing it with other if it 
was the culprit was my first option.  I have a spare Trimble oscillator 
that probably came from other NTGS50AA since it still have the foam band 
attached, but this oscillator is really aged, it needs 7.91 V to bring 
it on spot and the maximum control voltage of the NTGS50AA is 5 V.
I was trying to avoid removing the oscillator but probably it must be 
done to clarify things.


Thank you,
Ignacio EB4APL

.
El 12/11/2014 a las 2:40, Mark Sims escribió:

I have seen this caused by the oscillator not responding to the EFC signal.  
Fixed it by swapping in a MV-89 oscillator.
The oscillators used in these units don't output an oven temperature monitor 
signal.
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Re: [time-nuts] My NTGS50AA failed

[EB4APL]

Hi,
I found in the top side a quad op amp, a LT 1014, surrounded by your 
forest of resistors.  The output of one of these op amps goes directly 
to the control voltage input.  I'm in the right track.
It is very late here, 03:15 AM so I must go to the bed.  Working so late 
is a call for disasters ...


Best regards,
Ignacio EB4APL


El 12/11/2014 a las 2:54, Bob Camp escribió:

Hi

A .. I misunderstood what you were saying. As I now understand, the inputs 
to the DAC move around in the software, but the actual voltage out of the DAC 
is always stuck at 5V.

The DAC (if it’s like a TBolt) is the sum of a set of signals into an op amp. 
There is a forest of metal film resistors and several amps in the setup. About 
the furthest I’ve gotten it to trace the signals past the first layer op amp 
and find that one of them is *way* off making the op amp rail. I’m sure that 
there is somebody who has taken that process further. It looks like a setup to 
sum several PWM outputs, but I could easily be wrong.

Bob


On Nov 11, 2014, at 8:47 PM, EB4APL eb4...@cembreros.jazztel.es wrote:

Hi,
I meant 2 years, it is quite late here.
I'm not very sure that the DAC is working, I suppose that the unit doesn't 
measure the DAC output, it reports the DAC commands.  My voltage figures is 
what LH reports (so the NTGS50AA reports, probably what it is trying to do), 
but the frequency control pin of the oscillator is stuck at 5.02 V regardless 
of the supposed (intended) DAC output, it does not move at all.
I have checked the internal power supply voltages and they are ok. Hopefully a 
capacitor could be shorted to the +5V line but it looks too much luck for me.

Thank you for your suggestions,
Ignacio EB4APL


On 12/11/2014 a las 2:23, Bob Camp wrote:

Hi

Ok, the gizmo you have is pretty similar to a Thunderbolt in terms of what they 
did for circuits. It’s by no means identical and I have not traced either one 
out far enough to have a schematic.

At least from the TBolt - your DAC is working. The voltage is moving around and 
it’s getting low enough to bring the oscillator into lock. That suggests that 
the problem is not the DAC it’s self. I’d bet that what ever magic they do to 
figure out the oscillator frequency has gone nuts.  A very common approach is 
to use the GPS PPS like a gate on a frequency counter. I think that this part 
gets a bit more fancy than that. Either way, that sounds like where the problem 
lies.

Just in case - always check the regulated power supply voltages on the board 
and touch test the bypass caps. It’s a silly thing, but it doesn’t take long to 
do. I know I have gone for a few hours / days / weeks on something like this, 
only to finally bump into the shorted bypass cap or dead regulator and go 
“h…..”.

Bob



On Nov 11, 2014, at 8:07 PM, EB4APL eb4...@cembreros.jazztel.es wrote:

Hello,

After 2 yeses of continuous operation my NTGS50AA turned its red led on and stopped working. A 
check with LH shows OSC: BAD and OSC age alarm assuming that the oscillator 
had aged too much.
I didn't believe this because when working, the DAC control voltage was around 
2.9 V, in fact near the middle of its range (0-5 V). Measuring the 10 MHz 
output it is high, about 4.46 Hz which agrees with the LH figures.
I measured the oscillator EFC pin and it is struck at 5.02 V, not following the 
DAC voltages as reported by LH. I think that either the DAC is bad or an 
amplifier after it.  Since I don't have any schematic and the oscillator covers 
the top layer the troubleshooting is difficult.
Has anybody experienced this failure before?.  Does anybody has an schematic, 
even a partial one?

Since the unit now is operating open loop I observed the locking strategy of 
this GPSDO.  First it waits about 12 minutes for warming (I don't know if it 
internally monitors the oven current or uses a fixed time).  During this period 
it sets the DAC output to the initial value as stored in the EEPROM (3.0 V).
When it thinks that it is warmed enough, the DAC is ramped in the right 
direction to intercept exactly 10 MHz (towards 0 in my case). If it reaches 0 then 
declares the alarm and the DAC voltage is set to half the initial value (1.5 V). Five 
minutes later it switch the DAC to 2,25 V and 17 seconds later it returns to 1.5 V and 
remains there for 4 min and a half.  Then it goes up again to 2.5 V and after 10 seconds 
it goes down to 1.88 V and after some 14 minutes it goes down again to 1.5 V, it remains 
there for about 15 minutes and then it goes down to 1.14 V, remains there for 80 seconds 
and goes back to 2.5 V.
It looks like it checks from time to time if it is able to control the 
oscillator or simply it does weird things once it thinks that the oscillator 
cannot be disciplined.

I will appreciate very much any information.that can help my troubleshooting.  
These units has more than doubled its price since I bought mine and I think 
that they are vanishing.  The Guatemala's cell towers scrap has

Re: [time-nuts] [Bulk] There seems to be something missing from this eBay item.

[EB4APL]

Most damages are compatible with a truck fall but he BNC connectors are 
intentionally destroyed using a screwdriver or the like.  For me it 
looks like it came from an organization with a policy  of destroying the 
equipment that is written off.  I've seen this kind of things in the 
disposal facility of an Air Force Base.


Regards,
Ignacio EB4APL



On 07/11/2014 a las 2:24, Jim Lux wrote:

On 11/6/14, 5:08 PM, Scott McGrath wrote:
The only problem with these standards is the tube availability since 
they have that neat little rom which allows the standard to recognize 
the tube.


  So using available non-5071 tubes  is a challenge unless someone 
solved the rom issue


But the first one is pretty beat did someone have a bad day in the 
standards lab???





fell off the shelf, or was piled in a bin with a lot of other stuff.


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Re: [time-nuts] Varian R-20 Rubidium Frequency Standard

[EB4APL]

Paul,

You are right, NASA's Deep Space Network (DSN) used a pair of Sulzers in 
their Frequency and Timing subsystem.  At some time before 1972 they 
were replaced by a HP 5061A, a HP 5065A, and a HP Xtal oscillator, 
probably a HP 105B, the Sulzers remained in the rack several years but 
unpowered.
A curious thing that I remember is that the Cesium was used for the 
clock and all the timing, but the Rubidium was used for frequency 
reference for a lot of equipment, mainly for multiplying up to 
microwaves for the transmitters and receivers. When I asked why, I was 
told that they were more phase clean for this application.
Later an Hydrogen Maser replaced the Cesium as the primary reference and 
the crystal references were removed.
The MSFN used in the Apollo program used a different Frequency and 
Timing Subsystem.


Regards,
Ignacio EB4APL


On 05/11/2014 a las 15:27, paul swed wrote:

To a earlier comment I believe the NASA racks used Sulzers. Reason my 2 X
are NASA and still work just fine. :-)
Regards
Paul
WB8TSL

On Tue, Nov 4, 2014 at 9:33 PM, Bob Camp kb...@n1k.org wrote:


Hi

Yup I’ve seen that seller before. I’ve wondered a lot what they are up to.
Everything they sell is roughly 10X above the going rate. Most of it has
“buy it now” as an option.

If you need the manual, offer the guy the $25 that it’s worth and see what
happens. He may accept. Stranger things have happened. I’d only start the
process on something I REALY needed. Life is to short to play silly games
with some of these people.

Usual disclaimer - never bought from the guy, don’t know anything about
him, he may be a prince, he may have ties to the Society of Rome …I have no
idea.

Bob


On Nov 4, 2014, at 9:27 PM, EB4APL eb4...@cembreros.jazztel.es wrote:

Hi Adrian,

I found one at ebay,  item #251687322849 but the crazy seller wants $249

for it.  All his manuals and books are tagged with so exorbitant prices
which is a shame because its commercial value is nil.

Regards,
Ignacio



On 04/11/2014 a las 16:34, Adrian wrote:

I got a nice old Varian R-20 rubidium frequency standard that would be
nice to get working.
To begin with, there is at least a problem with the voltage regulator
circuit.

Does anyone have a manual? I couldn't locate anything on the web.

Regards,
Adrian
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Re: [time-nuts] Varian R-20 Rubidium Frequency Standard

[EB4APL]

In the Apollo era, NASA's Manned Space Flight Network tracking stations 
had a standard frequency rack called PFSS? which included a Varian R-20 
among a couple of crystal oscillators (HP or Sulzer, I don't remember 
quite well) and perhaps an HP 5065A with a switching matrix, 
distribution amplifiers and ancillary equipment..  These were the only 
R-20s that I have ever seen.


Regards,
Ignacio


On 04/11/2014 a las 16:58, paul swed wrote:

Wow varian made RBs. Learned something today and sorry no manual.
Regards
Paul
WB8TSL

On Tue, Nov 4, 2014 at 10:34 AM, Adrian rfn...@arcor.de wrote:


I got a nice old Varian R-20 rubidium frequency standard that would be
nice to get working.
To begin with, there is at least a problem with the voltage regulator
circuit.

Does anyone have a manual? I couldn't locate anything on the web.

Regards,
Adrian
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Re: [time-nuts] Varian R-20 Rubidium Frequency Standard

[EB4APL]

Hi Adrian,

I found one at ebay,  item #251687322849 but the crazy seller wants $249 
for it.  All his manuals and books are tagged with so exorbitant prices 
which is a shame because its commercial value is nil.


Regards,
Ignacio



On 04/11/2014 a las 16:34, Adrian wrote:

I got a nice old Varian R-20 rubidium frequency standard that would be
nice to get working.
To begin with, there is at least a problem with the voltage regulator
circuit.

Does anyone have a manual? I couldn't locate anything on the web.

Regards,
Adrian
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Re: [time-nuts] Racal-Dana tactile switches

[EB4APL]

Hi,

I did the same kind of replacement in my garden irrigation timer. It had 
membrane switches and I replaced them by ones very similar to yours, but 
because the switches were of the flat sandwich type it needed quite 
mechanical work.  Aesthetically the result was perfect, and the tactile 
feel quite superior.  I plan to do the same thing in my 1998 when it 
needs that.


Good luck,
Ignacio EB4APL


On 05/04/2014 22:53, Jim wrote:

Ulrich Bangert df6jb@... writes:


Gentlemen,

I know I am not the only one in this group to have difficulties with

weak

tactile switches on Racal-Dana's 1991/2/6 range of counters. The other day

I

talked to the chief technician at Rosenkranz-Elektronik which is one of

the

biggest surplus suppliers in Germany.

He knew the problem very well and his claim was that an exact replacement
for the original Toko switches is no more produced anywhere in the world.
Which may be an explanation why none of us managed to find an exact
replacement.
snip


I finally had to dive into my Racal Dana 1992 counter, after it had
developed several bad switches. I found that through-hole 6x6mm tactile
switches with four leads will fit in the counter pcb holes diagonally. That
is, if you trim off the leads from two opposite corners, the other two leads
are very close to the required distance to go into the existing pcb holes. I
just ordered some of these switches from ebay with a long plunger that looks
to be perhaps 2mm round. I'm going to drill holes into the back of the
existing keycaps to be a press-fit to the plunger on the new switches. I
think it will all hold together. If this works, it is a cosmetically and
functionally perfect solution. I'll report back after I've tried it.

The switches I picked are 6x6x10.5mm Tactile Pushbutton Switches,
ebay item 161008571229,

Jim



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Re: [time-nuts] Nav Receiver Sawtooth Correction?

[EB4APL]

Bob,

The sawtooth is generated by the granularity of the GPS receiver clock 
not being synchronous with the recovered PPS.  The receiver program can 
calculate the correction to be applied to the next PPS and outputs it in 
a message, bu only in timing receivers, this is not a useful thing in 
navigation receivers and I think that it cannot be calculated using the 
satellites' position, it is a receiver defect.
Why don't you buy a timing receiver?  An used Motorola Encore M12+ 
timing receiver can be bought by $35 or less (ebay items 290656401551 or
301131583613.  The seller is a known Time Nuts supplier).  An UT+ or GT+ 
even for quite less.


Regards,
Ignacio EB4APL




On 21/03/2014 20:28, Bob Stewart wrote:

I've gotten my PLL mostly working, but, since I'm using a nav receiver, it looks like I 
may want to see if I can do a poor-man's sawtooth correction based on GPS position 
changes.  Has anyone done this or have a reference for a project that has?  It would seem 
to me that only the East-West movements would be a factor, but I dunno.  As a beginning, 
I was just going to plot lat and lon deltas from gpsd data to see what 
correlates to the phase error jumps I'm seeing, unless this path has already been tread.  
I don't expect the accuracy that would be afforded by a real timing receiver.

Bob - AE6RV
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Re: [time-nuts] Time transfer, internationally before GPS

[EB4APL]

Since the original question was about alternatives to the traveling 
clock method before the advent of GPS, I remember two that were used by 
NASA to check the synchronization of their Deep Space Network facilities 
around the world.


- Moon bounce: A PN code was modulated on a microwave signal that was 
sent from the Mohave desert (there were a suitable transmitter - antenna 
there) to the Moon and its reflection was picked up in the facility to 
be synchronized.. To simplify the receiving equipment the code was 
continually compensated for the varying round trip distance between 
stations and it was correlated with a ramped model in the receiving 
end.  The output was drawn on a strip chart recorder and some 
interpretation was needed to estimate the clock difference.  The 
accuracy was said to be about 1 us but the system was not  very popular 
within the transmitter and the receiver crews.
-VLBI:  Among other observables, VLBI can be used to get very good 
estimations of the clock difference between stations.


A traveling clock was also used, there were lots of stories of afraid 
pasengers traveling close to the Atomic Clock  and for making the 
thing more frightening it was a HP Cesium with the Patek Philipe analog 
clock in the front conspicuously ticking.  They were assured that it was 
not an Atomic Bomb !!!.


Regards,
Ignacio EB4APL

On 04/03/2014 4:23, Bob Camp wrote:

Hi

One of the early relativity confirmation experiments was done with very similar 
clocks before that film clip was made. There were a number of corrections made 
as part of the trip. One of them was to re-confirm the traveling Cs once it got 
back to it’s starting point. You only could “use” the trip if the Cs came back 
home still on time.

There were a *lot* of satellite time transfer experiments in the 60’s and 70’s. 
They worked well enough to reduce the frequency of clock trips, but not well 
enough to eliminate them. The GPS common view stuff was the first approach that 
(with proper calibration) got them to a better level of time transfer than a 
clock trip.

Bob

On Mar 3, 2014, at 9:50 PM, Max Robinson m...@maxsmusicplace.com wrote:


The piece didn't say anything about correcting for acceleration.

Regards.

Max.  K 4 O DS.

Email: m...@maxsmusicplace.com

Transistor site http://www.funwithtransistors.net
Vacuum tube site: http://www.funwithtubes.net
Woodworking site 
http://www.angelfire.com/electronic/funwithtubes/Woodworking/wwindex.html
Music site: http://www.maxsmusicplace.com

To subscribe to the fun with transistors group send an email to.
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- Original Message - From: Jimmy Burrell jimmydb...@gmail.com
To: Discussion of precise time and frequency measurement time-nuts@febo.com
Sent: Monday, March 03, 2014 7:17 PM
Subject: [time-nuts] Time transfer, internationally before GPS



My apologies to the list if this has been posted before but I found it 
fascinating. I'm guessing this was early 60's.

I wonder if this practice continued until the advent of GPS? I be interested to 
know if there was an interim technology and what it was.

http://youtu.be/SXV4c5eVkE4


Jim...
N5SPE
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Re: [time-nuts] How I got my FE-5680A to lock in Sydney, Australia

[EB4APL]

Jim,

According to my log, my first unit sweeps from  9.999766 to 10.56 
and locks in less than 3 min.
My second unit sweeps from  9.9997414 to10.493 and also locks in 
less than 3 min.
Probably your unit needs to go a little bit higher.  The time spent at 
the limits probably is not relevant, I also noticed it and that they 
lock when reaching 10.0 MHz in the same ramp, I don't remember if going 
up or down.
But now that you are able to measure, what are the figures with the unit 
turned up and down?


Regards,
Ignacio EB4APL

On 09/02/2014 2:57, Jamieson (Jim) Rowe wrote:

Hi Magnus,

Thanks again for those further suggestions. I do have a GPSDO, and I 
had been able to use it with a counter to check that the FE-5680A was 
swinging either side of 10MHz. But I didn't make sure that it was 
swinging evenly each side of 10MHz . According to my notes it was 
swinging between  9.999770 and 10.36MHz -- i.e., about 230Hz low 
and about 36Hz high. But it was spending more of the time below 10MHz 
than above -- does this suggest to you that I should tweak C217 until 
it swings by about the same amount either way?


Cheers,

Jim


-Original Message- From: Magnus Danielson
Sent: Sunday, February 09, 2014 3:36 AM
To: time-nuts@febo.com
Subject: Re: [time-nuts] How I got my FE-5680A to lock in Sydney, 
Australia


Hi Jim,

On 07/02/14 05:19, Jamieson (Jim) Rowe wrote:

Hi Magnus,

Thanks for those suggestions also. So if I understand you right, I'd be
better off trying to tweak the oscillator tuning -- using the trimcap?
Or did you mean via the RS-232C 'offset adjustment' command?


I covered this in another message I just sent, but for completeness:

You want the C217 trim-cap adjusted such that the lock-in sweep will
sweep over 10 MHz, because that's where the synthesized magic locks up
and you get 10 MHz out.

If you use the offset adjustment, you could possibly get it to lock up,
but not producing the 10 MHz you expect.

Once you got the trick, it's actually quite fun to trim and get the warm
fuzzy feeling of fixing it as it locks up.

Cheers,
Magnus
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Re: [time-nuts] How I got my FE-5680A to lock in Sydney, Australia

[EB4APL]

Hi,

I second the idea about a mechanical issue.  When I opened my FRS-C I 
found that one of the connector pins had never been soldered, it only 
made mechanical contact with the PBC. Perhaps it showed an intermittent 
failure and was retired with low hours.


Ignacio EB4APL




On 07/02/2014 3:54, Ed Palmer wrote:

Hi Jim,

On 2/6/2014 3:32 PM, Jamieson (Jim) Rowe wrote:

Hi again folks,

You may (or may not) recall that a month or so ago, I asked for any 
information that might be available regarding how to fix a ‘used’ 
FE-5680A rubidium module from China (via ebay) which was tested by 
the supplier in China as working OK, but would not seem to lock up to 
rubidium here in Sydney. There wasn’t a great deal of info available, 
it seems, so I kept on checking ideas myself – mostly with no luck. 
The module would never lock, but kept cycling back and forth between 
about 9.999770MHz and 10.36MHz – ‘searching’ for a lock, but 
never finding it.


Anyway, a couple of days ago I was reading more about the operation 
of rubidium vapour oscillators, and noticed that the ‘filter cell’ is 
very sensitive to magnetic fields – hence the mu-metal shielding 
case, and also for the ‘C-tuning’ coil. And I wondered if the main 
reason why the FE-5680A  had apparently worked in China, but wouldn’t 
lock up in Sydney (Australia) might be caused by the fact that 
Quangzhou (China) is in the northern hemisphere while I’m ‘down 
under’ in the southern hemisphere – where the earth’s field is 
presumably somewhat different, in terms of both strength and direction.


So I decided to test this in a crude way, by inverting the FE-5680A 
and seeing what happened. And – lo and behold – it locked up within 
2.5 minutes, and stayed locked until I turned off the power and let 
it go cold again. The next morning I applied power again, and within 
3 minutes it locked up again with no problems. And it’s been locked 
up now for over 48 hours...


My first thought was to make a typical 'down-under' joke and suggest 
you run the 5680A upside down, but you beat me to it! :)


So it seems that the different magnetic field here may have been the 
problem – either that, or it may have received a ‘jolt’ in transit, 
which prevented in from locking unless it was inverted.


But how do I tell which of these explanations is right, without 
‘opening her up’ again and looking for some kind of subtle physical 
fault?


Another idea: perhaps the mu-metal shield case had acquired a small 
dose of magnetisation in transit (via a physical shock, or from a 
strong field metal detector). I guess in this case that I would have 
to remove the two halves of the case, and bake them in a furnace to 
demagnetise them again.


My very limited knowledge regarding mu-metal is that it is so 
magnetically 'soft' that it can't be magnetized.  If it was somehow 
magnetized, inverting the unit wouldn't make any difference, would it?


Or should I just run the FE-5680A upside down permanently – the 
simple but ‘crude’ answer?


I don't believe for a second (pun intended) that the earth's magnetic 
field has any effect on the locking of your 5680A.  It's just not 
strong enough.  The same applies to the C-field which can only nudge 
the frequency one way or another by a small amount.


Since flipping the unit DID make a difference, my money would be on a 
trivial, boring mechanical issue inside the unit.  Could be a bad 
solder joint, broken wire, floating piece of debris, or something like 
that.  Worst case might be a broken glue joint somewhere in the 
physics package.  That could be ugly.  I would definitely open it up 
and see if anything falls out.


I’m not sure if this FE-5680A has the ‘C-tuning’ gizmo fitted, or 
wired up. Am I right in thinking that another approach might be to 
try varying the tuning via the RS-232C serial port? Does this work 
via the C-tuning coil anyway, or by tweaking the DDS?


The RS-232 commands affect the DDS - assuming your unit does have 
one.  It will have no effect on the locking, only on the output 
frequency.


A few years ago I bought a dead Datum SLCR Rb standard.  It's a cousin 
to the LPRO.  I thought I'd learn some things by trying to fix it.  
The problem was intermittent.  I tore it apart and found that one of 
the legs of the crystal had never been soldered! Never overlook the 
obvious.


I hope a much more experienced time nut can provide a few answers, 
please.


Maybe the blind leading the blind is a closer description.

Ed


Jim Rowe


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Re: [time-nuts] Nortel GPSDO osc age alarm

[EB4APL]

Volker,

I have also a Trimble Nortel NTG550AA and fortunately it works very well 
from the beginning.  I have a downloaded manual and some other info that 
I can send you if interested.
And one word of caution: if you observe the cable that goes from the 
main board to the small interface board, you will see that one of the 
connectors is reversed so be careful if you make a custom one for your 
cabinet, do it in the same fashion.  Using a normal cable produces 
bizarre results that can actually drive you nuts, don't ask how I know.
The coax connector, J5 is a 9.8304 MHz output, an odd frequency used by 
the cell tower equipment, J4 carries 1/2 PPS (even seconds), the next 
one (J1) is the for the antenna and J4 is the 10 MHz output. You already 
know that but I want to note that the 9.8304 frequency has mislead some 
users to think that it was the 10 MHz output, not your case.


The seller (Bob Mokia , fluke.l) is well known to the Time Nuts, he has 
a technical background and normally known quite well what he sells and 
is very positive about solving the problems that may arise, his only 
problem is that his English is worse than mine .  I think that he 
regularly monitors this list.


I have observed a strange thing on this offering, at the end of the page 
he says:


power on it ...

after 30 minutes/it will locked/10mhz come on the SMB connector

1pps on the back d sub connector 

I never heard of a 1PPS signal on these units, only 1/2 PPS on the J4 
coax and I had asked on this list if anybody had found how to extract 1 
PPS from the unit.   I have to put a scope on the DSR pin because it is 
the only connected to the main board other than TxD and RxD.  Could you 
verify this on your unit when you change the OCXO and get it running?


Best regards,
Ignacio EB4APL


On 24/01/2014 16:23, Volker Esper wrote:

...thanks, Bob, it seems to be the oscillator, that is at it's limit, it
cannot tune to 10 MHz at full EFC voltage, see new thread (started by Mark).

Volker

Am 24.01.2014 01:09, schrieb Bob Camp:

Hi

That’s a cell phone base station board. It’s got a bunch of outputs, some of 
which are related to the cell network it was built for rather than 10MHz. I’d 
bet your 9.8 MHz output is one of those. They are DDS based so there likely is 
some range of possible outputs.

The age alarm is not unusual on a newly powered up board. It’s moving faster 
than it should. It may settle down.

The DAC at limit is not a real good sign ….

Bob

On Jan 23, 2014, at 6:43 PM, Volker Esper ail...@t-online.de wrote:


Hi!

I bought a Trimble/Nortel GPSDO

http://www.ebay.de/itm/300933951405?ssPageName=STRK:MEWNX:IT_trksid=p3984.m1497.l2648

and Lady Heather's now tells me that everything is alright - except
- DAC 6.04V
- OSC BAD
- osc age alarm

The rectangle 10MHz output signal (J5) shows a signal at about 9.8MHz
(a deviation of about 200kHz), wobbling 4Hz up and down. Oddly enough,
the direct oscillator output (J4) shows a sine wave at a stable
10.004MHz (a deviation of 0.4Hz).

It seems to me it's not the oscillator that is bad but the servo loop -
what can I do?

Thank you

Volker
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Re: [time-nuts] Lady Heather and the NTGS50AA

[EB4APL]

Hi Nigel,

Yes, I had tried Tboltmon v 2.60 but probably because it was very late 
and a senior moment  I didn't notice the GPSTM tab which precisely have 
the lights function that I was talking about, thank you for the hint.
The capability of turning the lights is not important, it is just 
aesthetics.  I have enclosed my board in a recycled HiFi cabinet, 
mounted the separate panel board at the front and  these monitoring LEDs 
are visible at the front panel.  Then I labeled them and now I have a 
permanent Comm fault ON and a Normal light OFF.  This is normal 
because the NTGS50AA is not communicating anymore with its intended cell 
tower equipment but it is annoying and I have to explain it to any 
friend who sees it and says Ignacio, you have an alarm!.
For all practical purposes I use  Lady Heather, it is plenty of useful 
functions and the author kindly added support for these boards when they 
appeared in eBay but unfortunately this version not handle the lights 
that are used only in there.


Regards,
Ignacio EB4APL



On 19/01/2014 10:26, gandal...@aol.com wrote:

Hi Ignacio
  
Your mention of the lights control had me confused for a minute, probably

not that difficult these days:-), because I do remember seeing that so was
wondering if the GPSTM tool had worked for me at one time after all.
  
However, a search through the various trimble programs reminded me  that

the Thunderbolt monitor, Tboltmon 2v60, has a GPSTM tab that does just this
and I've checked the LED control and that works ok here, although I'm not
sure  why I would ever need it.
  
I can't say whether or not the GPSTM tool has other options this lacks but

it might be worth a try anyway.
  
If you haven't already got it you should be able to find Tboltmon online

but I'm happy to send you a copy if you wish.
  
I've also found that the NTGS50AA is as vulnerable as other Trimble kit

when it comes to swapping about the various Trimble control programs, this one
  at the moment has decided to default to internal port B and so far refuses
  to permanently store any instructions to switch back again!!
Here we go again, anyone seen my hammer?
  
To return to the subject line though, Lady H still dives in  without

hesitation and just gets on with the job, she really is one  very capable 
Lady:-)
  
Regards
  
Nigel

GM8PZR
  
  
  
In a message dated 19/01/2014 01:12:45 GMT Standard Time,

eb4...@cembreros.jazztel.es writes:

Hi  Nigel,

The GPSTM tool (The program identifies itself as GPS Monitor v  1.5, to
contribute to the entropy) also gives the same errors when  connected to
my NTGS50AA, caused by bad programming that becomes crazy  when listening
to a device that sends data at 9600 Bd, but in the rare  occasions when
it syncs it works quite well and it has specific  Trimble-Nortel
functions for the NTGS50AA and its cousins, like the  ability to handling
the front panel lights.
Using the other GPS  monitor, the GPS Studio or even the Thunderbolt
monitor is easy as they  seems to recognize the baud rate but they lack
the special features noted  above.
I too prefer Lady Heather, it  is another kind (better) of  animal with a
lot of other useful  things.

Regards,
Ignacio


On 18/01/2014 17:19,  gandal...@aol.com wrote:

Hi Ignacio
   
I'm  not familiar with the GPSTM tool, trying to run it here gen.erates

  exception errors, but from what I see when it's trying to boot it's much

  the

same format as Trimble's various other  offerings.
   
If you run Trimble GPS Monitor though,  version 1.6 was the latest but

1.05

is fine too, and that  doesn't connect there's likely to be a box  showing
IDLE in the  bottom right hand corner of the displayed screen for  that.
If  you right click that you should get a drop down menu with the top item
  COM Port...
Left clicking that should bring up a small panel   for selecting Com  port
and settings with a tick button for  Auto-detect settings.
If you select that tick button and hit OK it  should run through all that
standard options for baud rate and  protocol etc and should hopefully find
whatever it's set to at the  moment.
   
I've just tried this with an NTGS50AA  that's been running with Lady

Heather

   and it very quickly  connected using TSIP at 9600-8-None-1.
   
Once  running in GPS monitor it's fairly straightforward to change

settings

  to what you prefer, at least it is for appropriate Trimble GPS modules

but

I haven't tried using it to make changes with the  NTGS50AA.
   
I have observed though that Lady  Heather can make other  unexpected

changes

at times.
I've  been playing with some Trimble Resolution T and Resolution SMT

modules

   recently, along with various different versions of  Trimble GPS

software as

   well as Lady Heather, and was  losing settings, apparently at random,
until I realised that Lady H  was changing the format for output data

such  as

position and  altitude etc to alternative formats that GPS Monitor and

Trimble

  Studio, for example

[time-nuts] Lady Heather and the NTGS50AA

[EB4APL]

I have a NTGS50AA working with the Lady Heather last version which 
incorporate support for this board (Thanks Mask Sims).
When I bought the board I used the Trimble utility GPS Monitor (GPSTM 
Commissioning Tool V1.5) to set it up and in the way knowing that it was 
previously  working in Guatemala.  This program uses COM1 or 2 with a 
fixed configuration of 19200, 7,Odd and 1stop bit. After using LH it 
seems that it changed the parameters to 9600.0.N,1 probably using an 
undocumented command and the board stores this configuration even if 
unpowered.  But now I can't use  the Trimble program because it refuses 
to connect, even it crashes when trying to connect at 19200 baud.  
Strangely it worked a couple of times when I was trying to command the 
leds in the panel but I don't know how it managed to change the baud rate.
Does anybody know how to change the configuration of the board serial 
port, maybe an undocumented command? I have the manual but I don't find 
anything neither in the LH documentation.


Regards,
Ignacio

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Re: [time-nuts] Lady Heather and the NTGS50AA

[EB4APL]

Oops, I meant Mark Sims, sorry.

Ignacio EB4APL


On18/01/2014 15:27, EB4APL wrote:
I have a NTGS50AA working with the Lady Heather last version which 
incorporate support for this board (Thanks Mask Sims).
When I bought the board I used the Trimble utility GPS Monitor (GPSTM 
Commissioning Tool V1.5) to set it up and in the way knowing that it 
was previously  working in Guatemala.  This program uses COM1 or 2 
with a fixed configuration of 19200, 7,Odd and 1stop bit. After using 
LH it seems that it changed the parameters to 9600.0.N,1 probably 
using an undocumented command and the board stores this configuration 
even if unpowered.  But now I can't use  the Trimble program because 
it refuses to connect, even it crashes when trying to connect at 19200 
baud. Strangely it worked a couple of times when I was trying to 
command the leds in the panel but I don't know how it managed to 
change the baud rate.
Does anybody know how to change the configuration of the board serial 
port, maybe an undocumented command? I have the manual but I don't 
find anything neither in the LH documentation.


Regards,
Ignacio

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Re: [time-nuts] Lady Heather and the NTGS50AA

[EB4APL]

I will try it, but always it happened after connecting the serial cable 
to the GPSDO that had been on for a long time.


Regards,
Ignacio




On 18/01/2014 17:07, Stanley wrote:

Ignacio,

The Strangely it worked a couple of times maybe it has auto baud 
routine that is active shortly after reset or power on.


Stanley

- Original Message - From: EB4APL eb4...@cembreros.jazztel.es
To: Discussion of precise time and frequency measurement 
time-nuts@febo.com

Sent: Saturday, January 18, 2014 8:27 AM
Subject: [time-nuts] Lady Heather and the NTGS50AA


I have a NTGS50AA working with the Lady Heather last version which 
incorporate support for this board (Thanks Mask Sims).
When I bought the board I used the Trimble utility GPS Monitor (GPSTM 
Commissioning Tool V1.5) to set it up and in the way knowing that it 
was previously  working in Guatemala.  This program uses COM1 or 2 
with a fixed configuration of 19200, 7,Odd and 1stop bit. After using 
LH it seems that it changed the parameters to 9600.0.N,1 probably 
using an undocumented command and the board stores this configuration 
even if unpowered.  But now I can't use  the Trimble program because 
it refuses to connect, even it crashes when trying to connect at 
19200 baud. Strangely it worked a couple of times when I was trying 
to command the leds in the panel but I don't know how it managed to 
change the baud rate.
Does anybody know how to change the configuration of the board serial 
port, maybe an undocumented command? I have the manual but I don't 
find anything neither in the LH documentation.


Regards,
Ignacio

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Re: [time-nuts] Lady Heather and the NTGS50AA

[EB4APL]

Hi Nigel,

The GPSTM tool (The program identifies itself as GPS Monitor v 1.5, to 
contribute to the entropy) also gives the same errors when connected to 
my NTGS50AA, caused by bad programming that becomes crazy when listening 
to a device that sends data at 9600 Bd, but in the rare occasions when 
it syncs it works quite well and it has specific Trimble-Nortel 
functions for the NTGS50AA and its cousins, like the ability to handling 
the front panel lights.
Using the other GPS monitor, the GPS Studio or even the Thunderbolt 
monitor is easy as they seems to recognize the baud rate but they lack 
the special features noted above.
I too prefer Lady Heather, it  is another kind (better) of animal with a 
lot of other useful things.


Regards,
Ignacio


On 18/01/2014 17:19, gandal...@aol.com wrote:

Hi Ignacio
  
I'm not familiar with the GPSTM tool, trying to run it here gen.erates

exception errors, but from what I see when it's trying to boot it's much the
same format as Trimble's various other offerings.
  
If you run Trimble GPS Monitor though, version 1.6 was the latest but  1.05

is fine too, and that doesn't connect there's likely to be a box  showing
IDLE in the bottom right hand corner of the displayed screen for  that.
If you right click that you should get a drop down menu with the top item
COM Port...
Left clicking that should bring up a small panel  for selecting Com  port
and settings with a tick button for Auto-detect settings.
If you select that tick button and hit OK it should run through all that
standard options for baud rate and protocol etc and should hopefully find
whatever it's set to at the moment.
  
I've just tried this with an NTGS50AA that's been running with Lady Heather

  and it very quickly connected using TSIP at 9600-8-None-1.
  
Once running in GPS monitor it's fairly straightforward to change settings

to what you prefer, at least it is for appropriate Trimble GPS modules but
I haven't tried using it to make changes with the NTGS50AA.
  
I have observed though that Lady Heather can make other  unexpected changes

at times.
I've been playing with some Trimble Resolution T and Resolution SMT modules
  recently, along with various different versions of Trimble GPS software as
  well as Lady Heather, and was losing settings, apparently at random,
until I realised that Lady H was changing the format for output data such  as
position and altitude etc to alternative formats that GPS Monitor and  Trimble
Studio, for example wouldn't or couldn't display.
  
It's easy enough to put them back, and once done they seem to survive

different versions of Trimble software as well as power cycling etc etc,  but
when run with Lady H they reset again.
Once aware of this I've just accomodated it and haven't bothered to
investigate further, so it's quite possibly something in a config file that  
could
be changed, but to be fair to Lady H, Trimbles own software isn't best
behaved at times either.
  
When running the NTGS50AA with GPS monitor just now I noticed the position

data is greyed out, even though it still displays fine with Lady H, but I'm
a  bit more cautious about tempting to configure these with Trimble's
software and  much prefer running them with Lady H anyway.
  
Regards
  
Nigel

GM8PZR
  
  
  
  
In a message dated 18/01/2014 14:57:03 GMT Standard Time,

eb4...@cembreros.jazztel.es writes:

I have a  NTGS50AA working with the Lady Heather last version which
incorporate  support for this board (Thanks Mask Sims).
When I bought the board I used  the Trimble utility GPS Monitor (GPSTM
Commissioning Tool V1.5) to set it  up and in the way knowing that it was
previously  working in  Guatemala.  This program uses COM1 or 2 with a
fixed configuration of  19200, 7,Odd and 1stop bit. After using LH it
seems that it changed the  parameters to 9600.0.N,1 probably using an
undocumented command and the  board stores this configuration even if
unpowered.  But now I can't  use  the Trimble program because it refuses
to connect, even it  crashes when trying to connect at 19200 baud.
Strangely it worked a  couple of times when I was trying to command the
leds in the panel but I  don't know how it managed to change the baud rate.
Does anybody know how to  change the configuration of the board serial
port, maybe an undocumented  command? I have the manual but I don't find
anything neither in the LH  documentation.

Regards,
Ignacio

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Re: [time-nuts] Schematic for the 'analog' section of an FE-5680A?

[EB4APL]

Jim,

I also found my notes for other unit.  It sweeps from 9.9997414 to 
10.493 and also locks in 3 minutes.


Regards,
Ignacio EB4APL



On 15/12/2013 2:26, EB4APL wrote:

Jim,

My unit, according to my notes, sweeps between 9.999766 MHz and 
10.56 MHz and locks in 3 minutes from cold start.  Maybe you have 
to move the frequency a bit towards the low side.


Regards,
Ignacio EB4APL


On 15/12/2013 0:27, ewkehren wrote:
One thing you also should do is set the tuning, even if it sweeps 
through 10 MHz if outside the lock range it will not lock. I have 
seen it.

Bert




Sent from Samsung tabletJamieson (Jim) Rowe 
jimr...@optusnet.com.au wrote:Hi Bert,


Thank you too for your tips and suggestions. I thought there might be 
'some'

analog circuitry in the 5680A, because the photodetector output from the
'far end' of the Rb resonance cavity probably needs some amplification,
before its 'strong enough' to be fed into an A-to-D converter. In any 
case

the schematic I found in the time-nuts archive doesn't seem to include
anything in the 'physics package' -- the Rb lamp oscillator, the 
microwave
oscillator feeding the resonance cavity, the photodetector and its 
output
amplifier or whatever. So it looks as if I'm going to have to search 
around

in that area myself...

Anyway Bert, thanks again and all the best for the festive season.

Jim Rowe
Sydney, Australia

-Original Message-
From: ewkeh...@aol.com
Sent: Saturday, December 14, 2013 12:49 AM
To: time-nuts@febo.com
Subject: Re: [time-nuts] Schematic for the 'analog' section of an 
FE-5680A?


Jim
unlike older Rb's there is very little analog in the unit. It is 
sweeping
trough its lock range so maybe you may find something around the  
lamp. The

lamp should not be the problem because the 5680 has not been around  and
been operating for extensive time before pulled.
How ever I like to caution time nuts and be careful who they buy from, I
did have a bad experience with one vendor and I did post it previously.
False claim of new and when returned after return authorization refused
refund
since I refused to give a 5 star rating. I forwarded the emails to 
ebay and

they did nothing. So any time nut that buys from ggg* fitting deserves
what he is getting. We have other sources out there that time nuts have
good
experiences with and with the price increasing by a factor of 4 one 
should

be careful. Personally I do not think they are worse the price
Bert Kehren Miami


In a message dated 12/12/2013 4:30:57 P.M. Eastern Standard Time,
jimr...@optusnet.com.au writes:

Hi,

I’m  an elderly time-nut newby, and I’ve already struck trouble with a
used FE-5680  Rb-vapour reference
I bought via eBay. It runs (from +16V and +5V), and the  current drain
starts at 1.75A and then drops over
5 minutes or so down to  about 650mA. But it won’t lock, even if I 
leave it

powered up for a few hours  (with a fan
to keep it from getting too hot).

The output frequency  just keeps switching up and down between about
850Hz and 1080Hz, with  a bit of ‘lingering’
near each end. And of course the ‘lock’ output at pin  3 stays 
stubbornly

at about 4.35V.

To my newby brain, this sounds like  the problem is either in the Rb 
lamp

(too dark, perhaps), or
else in the  photodetector and buffer, etc, forming the ‘dip detector’
part of the feedback  loop.

Could one of you much-more-experienced time-nutters tell me if my
diagnosis sounds right?

Also, I’ve found a schematic for the digital  sections of the 
FE-5680A in

your archives, kindly drawn up
by one of your  very experienced members, but has anyone done a similar
schematic for the  ‘analog’
sections?  I suspect I’m going to have to work out for  myself where to
test for a fault in these
sections. There’s also a  bit of a mystery (in my mind, at least) 
regarding

that little 2-pin SIL  header
just near the Rb lamp, on the top of the PCB. Anyone know what that’s 
for?


All the best in anticipation, folks.

Jim  Rowe


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Re: [time-nuts] Schematic for the 'analog' section of an FE-5680A?

[EB4APL]

Jim,

My unit, according to my notes, sweeps between 9.999766 MHz and 
10.56 MHz and locks in 3 minutes from cold start.  Maybe you have to 
move the frequency a bit towards the low side.


Regards,
Ignacio EB4APL


On 15/12/2013 0:27, ewkehren wrote:

One thing you also should do is set the tuning, even if it sweeps through 10 
MHz if outside the lock range it will not lock. I have seen it.
Bert




Sent from Samsung tabletJamieson (Jim) Rowe jimr...@optusnet.com.au 
wrote:Hi Bert,

Thank you too for your tips and suggestions. I thought there might be 'some'
analog circuitry in the 5680A, because the photodetector output from the
'far end' of the Rb resonance cavity probably needs some amplification,
before its 'strong enough' to be fed into an A-to-D converter. In any case
the schematic I found in the time-nuts archive doesn't seem to include
anything in the 'physics package' -- the Rb lamp oscillator, the microwave
oscillator feeding the resonance cavity, the photodetector and its output
amplifier or whatever. So it looks as if I'm going to have to search around
in that area myself...

Anyway Bert, thanks again and all the best for the festive season.

Jim Rowe
Sydney, Australia

-Original Message-
From: ewkeh...@aol.com
Sent: Saturday, December 14, 2013 12:49 AM
To: time-nuts@febo.com
Subject: Re: [time-nuts] Schematic for the 'analog' section of an FE-5680A?

Jim
unlike older Rb's there is very little analog in the unit. It  is sweeping
trough its lock range so maybe you may find something around the  lamp. The
lamp should not be the problem because the 5680 has not been around  and
been operating for extensive time before pulled.
How ever I like to caution time nuts and be careful who they  buy from, I
did have a bad experience with one vendor and I did post it  previously.
False claim of new and when returned after return authorization  refused
refund
since I refused to give a 5 star rating. I forwarded the emails  to ebay and
they did nothing. So any time nut that buys from ggg* fitting  deserves
what he is getting. We have other sources out there that time nuts have
good
experiences with and with the price increasing by a factor of 4 one should
be careful. Personally I do not think they are worse the price
Bert Kehren Miami


In a message dated 12/12/2013 4:30:57 P.M. Eastern Standard Time,
jimr...@optusnet.com.au writes:

Hi,

I’m  an elderly time-nut newby, and I’ve already struck trouble with a
used FE-5680  Rb-vapour reference
I bought via eBay. It runs (from +16V and +5V), and the  current drain
starts at 1.75A and then drops over
5 minutes or so down to  about 650mA. But it won’t lock, even if I leave it
powered up for a few hours  (with a fan
to keep it from getting too hot).

The output frequency  just keeps switching up and down between about
850Hz and 1080Hz, with  a bit of ‘lingering’
near each end. And of course the ‘lock’ output at pin  3 stays stubbornly
at about 4.35V.

To my newby brain, this sounds like  the problem is either in the Rb lamp
(too dark, perhaps), or
else in the  photodetector and buffer, etc, forming the ‘dip detector’
part of the feedback  loop.

Could one of you much-more-experienced time-nutters tell me if my
diagnosis sounds right?

Also, I’ve found a schematic for the digital  sections of the FE-5680A in
your archives, kindly drawn up
by one of your  very experienced members, but has anyone done a similar
schematic for the  ‘analog’
sections?  I suspect I’m going to have to work out for  myself  where to
test for a fault in these
sections. There’s also a  bit of a mystery (in my mind, at least) regarding
that little 2-pin SIL  header
just near the Rb lamp, on the top of the PCB. Anyone know what  that’s for?

All the best in anticipation, folks.

Jim  Rowe
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Re: [time-nuts] nortel trible NTBW50AA boards SCPI command access

[EB4APL]

Mark,

I'm interested also, my board is a NTGS50AA  but I think they are be 
compatible.


Regards,
Ignacio EB4APL



On 13/09/2013 17:06, Don Latham wrote:

Yes, please, Mark and thanks for the offer. I have one of these but
haven't got to it yet.

Don d'Huson

Mark C. Stephens

I have a couple of these boards and I have modified one to access the
SCPI command port available on the 'Z-Pack' rear connector.
The addition is simple but effective giving the TSIP front panel serial
port plus the cellular serial port.
Note that you will now have 2 separate connectors for the different
control modes.

One obvious use for the SCPI port could be for NTPD.
The NTBW50AA is lacking 1PPS but has a very accurate 2 Hz pulse ideal
for NTPD.

Unfortunately the :syst:stat? command is lacking in the firmware.

If anyone in interested in the details I'll prepare a doc and share?


--marki


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Re: [time-nuts] New NTBW50AA

[EB4APL]

Dave,

I have a cousin of your GPSDO, a NTGS50AA whose main differences are 
that in this unit the DB-9 connector and the LEDs are in a separate 
board connected by a flat cable, and that this unit is meant for -48 
volts systems only.


The yellow light indicates that it is not in communication with the 
mainframe for about 30 seconds so it is labeled comm error.  There are 
two ways to turn it green:
-  Emulate a small subset of the mainframe protocol with a 
microcontroller and communicate with the board through the 110 pin 
connector in the back.  Nothing useful and quite complicated.
- Ask Mark Sims to include in LH a function to periodically send a 
command to turn the lamp green.  I verified with the Trimble-Nortel 
installation tool (GPS_Monitor) that if you tick the box for commanding 
the LED to green, it stays green until the program quits, so it is 
periodically resetting the comm timeout counter.  With this function the 
LED would be green as long LH is in communication with the box and would 
turn yellow if the program quits or the communication is lost, like when 
the box is installed in a cell tower.



Just an idea,
Ignacio EB4APL


On 10/09/2013 4:31, quartz55 wrote:

OK, did a bit more reading.  I already understand the difference between 
accuracy and stability however.

I thought ADEV was some sort of measurement of accuracy, but I understand now it 
is a measure of stability over time.  I'm supposing now that I can assume that the 
best frequency accuracy I can imagine is what is specked in the book for the unit, 
.8x10^-10.  That should be good enough for me.  Although most seem to say the 
GPSDO units are good for .1Hz at 10GHz which I think would be 10^-13 no?

Yeah, I've read through the h...cpp and a lot of it is greek to me, I'm no 
programmer, but I can pull a bunch of stuff out of it.  But it doesn't explain 
the acronyms or the meanings of them.

I've lowered the el mask to 20 and I get plenty of sats now.  When it was at 
43, lots of times it was down to 2, now it's generally up to 6.  I'll see how 
it does, especially if it rains, and yes the trees really cover the antenna.  I 
am getting 30-40 or more dBc however which is what I had when it was more in 
the clear.  I can move it to the west about 30' on the chimney where my UHF/VHF 
beams are and it's a lot more open straight up and especially to the south.  
The position where it is now is just real convenient and it's only maybe 25' 
from the unit.  Plus I didn't have to get up on that part of the roof that's 7 
in 12.

Yes, I notice the gis for our county seems to have a slightly different 
co-ordinate system, they don't line up with google or the GPS which seem to 
agree as far as I can zoom in on our location.  I'd say the GPS and google are 
within a foot or 2.

I guess I can just turn off the temp chart if it's not going to report right 
and stop looking/worrying about it.  As long as the green lock light is on.  I 
wonder if I could trick the Nortel unit into thinking it's seeing the CM 
though, so the top green light would come on instead of the yellow one.  But 
that doesn't matter.

Thanks for all your help, I'll hang around for a while.

Dave
N3DT



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Re: [time-nuts] New NTBW50AA

[EB4APL]

Hi,

I have a a small correction to my message, I was talking from memory.
After checking with the real thing I found that 2 commands are needed:  
One for turning the yellow LED (Comm fault) off and other for turning 
the Green one (Normal) on.


Ignacio EB4APL


On 10/09/2013 13:47, EB4APL wrote:

Dave,

I have a cousin of your GPSDO, a NTGS50AA whose main differences are 
that in this unit the DB-9 connector and the LEDs are in a separate 
board connected by a flat cable, and that this unit is meant for -48 
volts systems only.


The yellow light indicates that it is not in communication with the 
mainframe for about 30 seconds so it is labeled comm error. There are 
two ways to turn it green:
-  Emulate a small subset of the mainframe protocol with a 
microcontroller and communicate with the board through the 110 pin 
connector in the back.  Nothing useful and quite complicated.
- Ask Mark Sims to include in LH a function to periodically send a 
command to turn the lamp green.  I verified with the Trimble-Nortel 
installation tool (GPS_Monitor) that if you tick the box for 
commanding the LED to green, it stays green until the program quits, 
so it is periodically resetting the comm timeout counter.  With this 
function the LED would be green as long LH is in communication with 
the box and would turn yellow if the program quits or the 
communication is lost, like when the box is installed in a cell tower.



Just an idea,
Ignacio EB4APL


On 10/09/2013 4:31, quartz55 wrote:
OK, did a bit more reading.  I already understand the difference 
between accuracy and stability however.


I thought ADEV was some sort of measurement of accuracy, but I 
understand now it is a measure of stability over time.  I'm supposing 
now that I can assume that the best frequency accuracy I can imagine 
is what is specked in the book for the unit, .8x10^-10.  That should 
be good enough for me.  Although most seem to say the GPSDO units are 
good for .1Hz at 10GHz which I think would be 10^-13 no?


Yeah, I've read through the h...cpp and a lot of it is greek to me, 
I'm no programmer, but I can pull a bunch of stuff out of it.  But it 
doesn't explain the acronyms or the meanings of them.


I've lowered the el mask to 20 and I get plenty of sats now. When it 
was at 43, lots of times it was down to 2, now it's generally up to 
6.  I'll see how it does, especially if it rains, and yes the trees 
really cover the antenna.  I am getting 30-40 or more dBc however 
which is what I had when it was more in the clear.  I can move it to 
the west about 30' on the chimney where my UHF/VHF beams are and it's 
a lot more open straight up and especially to the south.  The 
position where it is now is just real convenient and it's only maybe 
25' from the unit.  Plus I didn't have to get up on that part of the 
roof that's 7 in 12.


Yes, I notice the gis for our county seems to have a slightly 
different co-ordinate system, they don't line up with google or the 
GPS which seem to agree as far as I can zoom in on our location.  I'd 
say the GPS and google are within a foot or 2.


I guess I can just turn off the temp chart if it's not going to 
report right and stop looking/worrying about it.  As long as the 
green lock light is on.  I wonder if I could trick the Nortel unit 
into thinking it's seeing the CM though, so the top green light would 
come on instead of the yellow one.  But that doesn't matter.


Thanks for all your help, I'll hang around for a while.

Dave
N3DT



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Re: [time-nuts] Rb video

[EB4APL]

I bought one of these DA's from the same seller and according to the 
user's guide the BW is 300 MHz, fully loaded.  I didn't measured it but 
it works very well at 10 MHz.


Regards,
Ignacio EB4APL


On 08/08/2013 3:39, Mark C. Stephens wrote:

Seems they are rated to 5MHz according to the manufacturer..
They ebay item number is 161081736069.

--marki

-Original Message-
From: time-nuts-boun...@febo.com [mailto:time-nuts-boun...@febo.com] On Behalf 
Of Eric Garner
Sent: Thursday, 8 August 2013 5:57 AM
To: Steve G8EBM; Discussion of precise time and frequency measurement
Subject: Re: [time-nuts] Rb video

what's the performance of the distribution amplifier like?


On Wed, Aug 7, 2013 at 9:12 AM, Steve G8EBM st...@g8ebm.com wrote:


Great video.  The distribution units are still available on eBay.  I
bought two today.

Regards

Steve G8EBM

-Original Message- From: David J Taylor
Sent: Tuesday, August 06, 2013 11:30 AM
To: Time Nuts
Subject: Re: [time-nuts] Rb video

Found this on Hack-a-day

http://www.youtube.com/watch?**v=chrzrod3tQYhttp://www.youtube.com/wa
tch?v=chrzrod3tQY

Cheers

Raj, VU2ZAP
Bangalore, India.
==**=

Thanks for the pointer - I enjoyed that, particularly the PIC programming!

73,
David GM8ARV
--
SatSignal Software - Quality software written to your requirements
Web: http://www.satsignal.eu
Email: david-tay...@blueyonder.co.uk
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_
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Re: [time-nuts] Nortel Trimble thunderbolt

[EB4APL]

Is this Trimble Thunderbolt the Nortel-Trimble NTGS50AA board?  I had 
a problem with the com port of my unit upon removing it from the cabinet 
for some improvements.  After driving me nuts the problem was caused by 
the internal com cable which had a factory reversed connector that was 
unnoticed before.  I had put the full story recently on this list.


Regards,
Ignacio EB4APL


On 06/07/2013 18:56, Jim Sanford wrote:

All:

This is still not going well.

I have tried 3 different computers, 2 running Win7 and one running 
XP.  the XP machine successfully controls an Icom radio on the same 
port, so I know the port is good.  I have tried a new serial cable. I 
have tried with and without a null modem.


No matter what I do, Lady Heather reports no serial communications on 
comm/x.


/Thanks  73,
Jim
wb4...@amsat.org
/
/
On 7/6/2013 10:44 AM, Ed Palmer wrote:
Certainly if you need a full implementation with various control 
leads you might have to dig out the breakout box and figure it out. 
But the volts / no volts idea is still useful for connecting pairs 
like RTS/CTS or DSR/DTR.  But I'm surprised how many devices don't 
use the control leads.  Most of the devices I work with don't even 
use software flow control.


Ed

On 7/5/2013 10:06 PM, Chris Albertson wrote:
On Fri, Jul 5, 2013 at 7:03 PM, Ed Palmer ed_pal...@sasktel.net 
wrote:



I always cursed when I tried to figure out how to wire an RS232 cable
until I realized that transmit had a voltage on it while receive 
was close
to zero volts.  So now I just remember that volts on one end 
connects to no
volts on the other end.  Works every time and I don't have to think 
about

straight or cross-over.


That only works if there are only three wiresand no handshaking.  
What if

there is DTE/DCE and so on?

But I think in this case it is just a three wire connection but 
still there

is room for errors like for example is one of them a TTL level and the
other RS-232.  Some times you can mix the two, sometimes not.





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Re: [time-nuts] Connector For Trimble/Nortel GPSTM (NTGS50AA) ?

[EB4APL]

Hi,

I also connected it directly, the weird 110 pin connector probably costs 
more than I paid for the NTGS50AA.  If in the future I want to use any 
signal present in the connector it can be done using small individual 
pins.  Now the question, has somebody successfully used the internal 
serial port (the one that goes to CM, the cell tower equipment)? It 
could be a weird mean of turning the yellow Comm fault led off and the 
green In service one if conveniently used with a PIC or equivalent 
microcontroler. According to the available documentation they speak SCPI 
(the same as used in the GPIB, I think) over an EIA-485 physical layer, 
but no mention is made of the commands used, the only thing that is 
clear is that indicates no communications with the CM in the last 60 
seconds.  Just sending anything that triggers a response could be enough.


Regards,
Ignacio EB4APL


On 03/06/2013 18:42, Bob Camp wrote:

Hi

That's what I have done. Cheaper and (hopefully) more reliable than a
connector.

Bob

-Original Message-
From: time-nuts-boun...@febo.com [mailto:time-nuts-boun...@febo.com] On
Behalf Of Frederick Bray
Sent: Monday, June 03, 2013 10:57 AM
To: Discussion of precise time and frequency measurement
Subject: Re: [time-nuts] Connector For Trimble/Nortel GPSTM (NTGS50AA) ?

So, I gather that most folks are just connecting power to the
appropriate 2 pins on the 110 position connector.  I wasn't sure whether
people were wiring directly to the DC converter.

Thanks.

Fred


On 6/3/2013 3:53 AM, Erno Peres wrote:

there is only a 48Volt connection and some unknown data com I did not

use any mating connector just the power in... everything is available on the
front plate.



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Re: [time-nuts] FE-5680A control programs

[EB4APL]

Hello,

Thank you to all who responded.
I was playing with the idea that apart from the offset setting, 
retrieving and storing it in the EEPROM, probably there were 
undocumented commands for other functions like knowing the status and 
health of the unit, like on other Rubidiums or the analog outputs in the 
FRS series.  Some programs that I had downloaded and stored waiting 
until I had time to put the FE-5680A into use were in fact for the 
programmable variety, like Ruby4.exe.
I was looking for something as the program fe5680_info_win32.exe from 
Newell N5TNL mentioned in this list on Jan 25 2012, that dumps a lot of 
info from the unit but with the commands and responses translated to 
plain language.  In fact I´m not sure if this program applies to my 
FE-5680A or it is intended for the programmable output ones.
For setting the calibration offset I use Fe5680Calibrator.exe which is 
on this line but it do not send other commands.
And I don't have any source others than the Fabio Eboli's Python scripts 
already mentioned.


Best regards,
Ignacio EB4APL


On 24/05/2013 21:02, Chuck Forsberg WA7KGX N2469R wrote:
I added a command to display or change the frequency offset to my 
ZCOMM program.


To use it:

port 1
fe [new offset]

On 05/24/2013 05:06 AM, Ziggy9 wrote:
A few months ago Fabio Eboli posted some Python functions that might 
be useful. I haven't used or tested them myself, but they might be of 
interest. Still up on pastebin at


http://pastebin.com/download.php?i=VpZVuw0t

I don't know if Fabio has done any further work on this but perhaps 
he'll chime in here.


Paul

On May 24, 2013, at 0:22, Chris Albertson albertson.ch...@gmail.com 
wrote:



You have been collecting programs?  I did not know there were any to
collect.  Do you have a list?   I don't have much use for a .exe 
file but

is your are source codes available that would be great.


On Thu, May 23, 2013 at 4:44 PM, EB4APL 
eb4...@cembreros.jazztel.es wrote:



Hello,

Since I bought my FE-5680A (10 MHz, 1 PPS variety), I have been 
collecting
control programs for it and keeping then in reserve.  Now that I'm 
going to
box it with a distribution amp I tried some of them, first of all 
to adjust

the frequency against the GPS.  I used Bob Campbel's VK4XV
Fe5680Calibrator.exe with good results.  I have other programs which
interrogates the device and shows the hex dumps, but I would like 
to know
if there is a windows program that allows to send other that the 
offset

related commands to the device and get the responses not in hex but
translated to plain language. In fact I don't know if there are
housekeeping commands for reading thinks like the lock status or 
the lamp

voltage like the analog outputs of the  FRS-C and others.

Thanks in advance,
Ignacio EB4APL
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[time-nuts] FE-5680A control programs

[EB4APL]

Hello,

Since I bought my FE-5680A (10 MHz, 1 PPS variety), I have been 
collecting control programs for it and keeping then in reserve.  Now 
that I'm going to box it with a distribution amp I tried some of them, 
first of all to adjust the frequency against the GPS.  I used Bob 
Campbel's VK4XV  Fe5680Calibrator.exe with good results.  I have other 
programs which interrogates the device and shows the hex dumps, but I 
would like to know if there is a windows program that allows to send 
other that the offset related commands to the device and get the 
responses not in hex but translated to plain language. In fact I don't 
know if there are housekeeping commands for reading thinks like the lock 
status or the lamp voltage like the analog outputs of the  FRS-C and others.


Thanks in advance,
Ignacio EB4APL
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Re: [time-nuts] Precise positions for GPSDOs

[EB4APL]

I fully agree with Chris, do not trust Google Earth for any serious 
technical use, I found errors in 100-200 m range.  You only need to 
check where two images are stitched.
Google Earth images are not produced by Google, they get them from other 
companies or government bodies involved in making geographical 
information, I can't speak about it in a whole but I actually know cases 
in what Google tried to get the info for free. The metric quality (or 
QUALITY) is not controlled by Google as far as I know. Think of Google 
Earth as a means of providing geographical information for the layman, 
for finding places, advertising  and so but you don't know how accurate 
it is, even the date of the images can be erroneous, you can verify this 
yourself.
I had professionally advised many customers to not rely on this info for 
any serious use, giving them actual examples.  It is a very good and 
amazing product but its goal is not to make any precise measurement, and 
the GPS antenna position determination is in fact a surveying task.


Regards,
Ignacio EB4APL



On 02/05/2013 17:19, Chris Albertson wrote:

Google maps is NOT that good, it can be off by a lot, tens of meters.

I had to have my property line surveyed some years ago to get a city
building permit. So now I have two brass markers at know position.
The survey crew used traditional transits from a brass benchmark.
Google Earth thinks these brass markers are a few meters from here the
survey crew said. (Yes I know about WGS84, we are all working in that
system)

I think the problem is that the lland is not flat here.   If I lived
in Kanas the Google system might work.   But I don't think Google
warps the images to account for hills and even slopes.  I don't know
the source of Google's error.  The 1 Sigma on the self survey is about
.5 meters more or less.

I think the best why to measure is to let the self survey run for a
full 24  hours so you get two full orbital periods of each satellite.
And also to  make sure you have 360 degree view of the sky.I think
a view in only one direction might be biased.

But yu can check Google.  Find a few brass government benchmarks near
your house and have Google locate them and if you got a match go with
Google

On Thu, May 2, 2013 at 2:29 AM, Stewart Cobb stewart.c...@gmail.com wrote:

A GPSDO typically makes the assumption that the position of its antenna is
fixed and well-known. That removes position uncertainty from the navigation
equations, and allows all the information from the satellite measurements
to be used to improve the time estimate. Errors in this position create
errors in timing, with a magnitude scaled by the speed of light (one ns per
foot, three ns per meter).

Most GPSDOs do some sort of position averaging when they are first turned
on, to come up with a good-enough estimate of antenna position. For a true
time-nut, that might not be good enough.

GPS surveying equipment can easily determine the position of your antenna
to within a few centimeters (~20 ps). Unfortunately, such equipment is
expensive and difficult to borrow.

A high-end GPSDO designed today should have the ability to record phase
data into RINEX files, which could be sent to a service like OPUS to find
the antenna position.

http://www.ngs.noaa.gov/opus/

But few do, so far.

The next best idea is to locate your antenna on Google Maps. Type in the
self-surveyed position to the Google search box, either as decimal degrees
or as DMS, formatted like this but without the quote marks:

37.384542, -122.005526

37 23 4.35, -122 0 19.89

Click on the map and zoom in. Click on the Map box in the upper right and
uncheck the 45 degree view icon. Then right-click on the spot on the
picture where your antenna is actually located, and select What's here?
from the pop-up menu. A green arrow marker will appear, pointing to your
antenna. Left-click on the arrow, and read your latitude and longitude in
both formats. Enter one of them into your GPSDO, replacing the self-survey,
and enjoy increased accuracy.

A true time-nut will take one more step to improve accuracy. (Sorry, but
the rest of this is specific to North America. Similar details apply to
other parts of the world, but I only know the recipe for the place I live.)

Google Maps photos are registered (quite accurately) to the North American
Datum NAD83. Unfortunately, your GPSDO operates in a different datum
known variously as WGS84, ITRF, or IGS (these are all essentially the
same). The difference between these two datums can be a couple of meters,
easily visible on the map photos and worth 5 ns or more of time error.
Fortunately, you can convert NAD83 to ITRF2008 at this website:

http://www.geod.nrcan.gc.ca/apps/tmobs/tmobs_e.php

For ITRF epoch, just enter today's date. For ellipsoidal height, use
the value from your self-survey if you don't have a better one. You might
be able to get a better one from Google Earth, or by finding a nearby
benchmark from this site (US only

Re: [time-nuts] Italian Time Station on 10 MHz ?

[EB4APL]

Hi Iain
It is operating from mid 2012 at least, I started a thread about it on 
06/29/2012  when I noticed it and several members responded with their 
opinions.
It seems to be more a pirate station than an experimental station, I 
have serious doubts that they may have a license for it.
For starting their announced web page www.italcable.it redirects to 
www.associazioneitalcable.it (Italcable was a historic 
telecommunications company now merged into Telecom Italia).
The site has just a page without any explanation about the association 
and his goals and only announces their Open Source Sensors and the 
Time Signals stations on 10 MHz and 15 MHz both defined as amateur and 
experimental station. They also include an email address, a postal 
address and under License they say Authorized by the Ministry of 
Economic Development.  I suppose that is the license for operating the 
association, not the radio stations.
The 10 MHz station frequency is almost 4 Hz down since the beginning, 
the 15 MHz transmission, new for me, is much more on frequency, less 
than 1 Hz high.
The pips are at 1110 Hz above the carrier, I did not made any effort for 
reading the code, even it could be fake, neither how good is its time .
And their use of music for filling the idle time severely interferes 
with legitimate time signals in these frequencies.

Also, according to some local hams, the stated transmission site is faked.

Best regards,
Ignacio EB4APL


On 28/04/2013 14:43, Iain Young wrote:


Hi Folks,

A friend of mine sent me a You Tube recording of an unidentified Time
Station on 10MHz, possibly from Italy or Brazil. Further work seems to
suggest it is indeed an experimental time station from Italy.

Below is a (modified for context) version of the email I sent him:

--BEGIN INCLUDE MESSAGE---

At first look, I tend to agree with others that it's a new
experimental Italian Time Signal. It is also shown on this
You Tube link:


http://www.youtube.com/watch?v=VSQyKh694RU

Video claims to be: Experimental Time Signal from the italian private
socitey Italcable transmitting at 1KHz

Three observations from this recording:

a) The pips are about ~1k up from the main carrier on 10MHz.
Probably a little higher, maybe 1.1k

b) Right at the beginning, there is a burst of digital comms, that
to my ear sounded similar to 300 baud packet. Checking the Frequency
vs Amplitude display in the bottom left again, it appears that that
burst is up at ~2k+ from the 10MHz centre

Now...a PK232 running 300 baud uses the following frequencies:

2110 Mark, and 2310 space tones as a PK-232, with the center of the
tones being 2210 Hz, and going fullscreen on the video suggests that
the spikes during that burst are smack where we would see them for
300 baud packet when using a PK-232.

(With the resolution of the youtube video and the screen, thats as
accurate as I can get)

c) The burst does appear to repeat later in the recording, which
suggests it may be part of the time code, rather than some
Italian APRS station being a tad off frequency


I would suggest that the next step would be to put a 300 baud
PK232 MODEM on 10 MHz, and record anything that gets decoded.

If its ASCII (highly unlikely to be KISS Frames unless it is someone
way off frequency, and c) above would seem to suggest that's less
likely, then it may well be the time of day.

In that case, in order to use it, we need to work out the reference
point. There seems to be six pips 1 second apart, a gap of a two
seconds, followed by a final seventh pip.

While different to Radio 4's longer final pip, this is similar
to DCF where the final second of the minute is not modulated (MSF
does something similar with a 500mS carrier off at the beginning
of the minute.

My guess is the seventh pip identifies the start of the minute,
with the 6 pips beforehand being used for receivers to lock on,
and identify the 2 second gap, with the 300 baud packet being
used to carry the time information itself for the next minute.

Now, do you have the ability to listen on 10MHz with a PK232
tones sound MODEM ? :)

---END INCLUDE MESSAGE---

I am hoping to get a recording or two of it (I don't have HF
RF capability right now, but do have replay and 300 baud decode
capability), to see if it really is 300 baud packet, but have any
(Probably European) time-nuts hear this signal ?

Anyone have any details on the time code ? I'm going to hope it
might be possible to decode the time from the packet burst, but
if anyone has any prior knowledge, then a head start is never a
bad thing when trying to decode these things :)

(BTW, the station seems to play music most of the minute, which
quietens during the packet burst and pips)


All the Best

Iain


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Re: [time-nuts] Brooks Shera ASM release

[EB4APL]

Bert,

As one of Brooks customers I would like to express my thanks to him 
for his generous work (fortunately I did it when we contacted in early 
2009), and also now to thank you and the others who made possible to 
finally have his code, including the efforts to fix and test it.

And of course thank his widow for letting this to happen.
I was traveling abroad when you posted the code and intermediately 
downloaded and secured it while at the airport.  Back home now it is the 
time to say thank you all.


Best regards,
Ignacio EB4APL

On 15/04/2013 21:17, ewkeh...@aol.com wrote:

Alan
You may suggest something to time nuts, looking at the response I doubt it
and ask my self why did three of us spend three weeks to fully check it out
and  fix some of the code. Will reflect future projects.
Bert Kehren
  
  
In a message dated 4/12/2013 8:39:40 P.M. Eastern Daylight Time,

alan.me...@btinternet.com writes:

Bert is  there any way we can add our names to some expression of thanks to
his  widow Karen and her helpers for their work and maybe leave a
remembrance
of his worldwide friends for his family?

Thanks for your  efforts
Best wishes
Alan Melia  (G3NYK)
UK





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Re: [time-nuts] FE-5680 frequency jump

[EB4APL]

Thank you for the info, I used to attach a magnetic mount surface 
thermometer to my FRS-C to check its operating temperature after 
installing it in a box.  I think it is time to power it up and after 
some days check it against the GPS.


Regards,
Ignacio EB4APL


On 05/04/2013 20:59, Bob Quenelle wrote:

I found the cause of the 4 mHz  frequency jump.  I have an LPRO-101, an
FE-5680, power supplies and a Motorola M12T GPS board in a surplus case.
When I put the case away to work on another project I piled the hockey
puck antenna and lead in the case and it happened to land on the
FE-5680.  I noticed the antenna stuck firmly to the FE-5680 case when I
got the project back out.  I found I could get a 6 mHz (0.6 ppb) shift
comparing the frequency with residual magnetism from the magnet stuck on
the FE-5680 case to the frequency after demagnetizing the FE-5680 case.
Unintentional C field adjustment.  Dope slap, live and learn.
Bob


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Re: [time-nuts] Brooks Shera

[EB4APL]

I wanted to build a GPSDO using the Brooks Shera design since I read the 
QST article.  I asked him in Jan 2009 about his source code, because I 
wanted to change the PIC to a more modern one and add some 
functionality, and his response was that he already had changed it to a 
16F876A and added a lot of improvements to the released code such as PC 
control of many parameters using a COM port and in his opinion it was 
better for me to order a pre-programmed PIC from him than trying to 
reinvent the wheel.
I did it and also he was kind enough to provide me with all the 
hard-to-obtain parts.
My chip has this last version (402NE is mentioned in the doc, but this 
is from 2007 and there is a later version), but probably it has the 
fuses set to avoid extracting the code.  Maybe somebody has the hex or 
the source of this improved version, in the documentation it is 
mentioned that Bob Leichner (WO6W) collaborated with Brooks in this 
version so he can be a source of more info.


Brooks also made a PC program for controlling the GPSDO and plotting its 
performance (EFC, ADEV, etc.).  The program can be downloaded from:

https://sites.google.com/site/bshera02/software
and
https://sites.google.com/site/bshera02/software2
(you need both downloads).
I also have a description of the serial port commands accepted by the 
device.
I have all parts and the PCB stored because I got a Trimble GPSDO, but I 
think this is the right time to assemble it, at least as a tribute to 
Brooks.

If anybody wants the files, just ask.

Best regards,
Ignacio EB4APL


On 24/03/2013 19:31, Chris Albertson wrote:

On Sun, Mar 24, 2013 at 4:12 AM, Stephen Tompsett (G8LYB)
step...@tompsett.net wrote:

Here's a copy of the source package (that claims to be for version 1.28)
that he sent me when I enquired about it many years ago.


That's great.  It needs to be some how linked to an archive of his
article.  No better memorial to an engineer than to have is work
preserved in a public place.   I read the assembly source code.  I'm
not a PIC expert but I've been doing software for 25+ years I and see
that it is well written and easy to understand.   Some day I'll
transliterate this to run on a TI launchpad and will have to credit
the author.


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Re: [time-nuts] Tube/valve mounted xtals....

[EB4APL]

Here you have one of these crystals, it is a 62.500 Kc/s unit used in a 
Marconi TV studio sync generator in the sixties.

http://s1338.beta.photobucket.com/user/EB4APL/media
/CAM00431R_zps07fdcbf4.jpg.html

Ignacio, EB4APL


El 07/03/2013 15:45, Lee Reynolds escribió:

as young Nigel said, Marconi (for one) made use of these things. I
recall a Marconi HR-22 that had a number of these installed for spot
frequency channel reception.

Lee
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Re: [time-nuts] webcam app to watch for and time stamp changes

[EB4APL]

When LCD wristwatches became common in the seventies we, in the 
frequency and timing group of a space tracking facility, investigated 
the possibility of adjusting our new watches against our standard.
We found that a a small copper plate, about 1 X 2 cm, resting against 
the display and connected to a scope probe was able to pick up enough 32 
KHz energy to be displayed in the scope.  Then connected the vertical 
output to an HP 5245L counter referenced to our standard and set the 
gate time to 10 seconds and got the frequency.  We learned that the 
watch had to be worn in order to operate at the right temperature, the 
body acting as an oven, so you has to wear it backside in order to 
access the trimmer (yes, at that time those watches had and adjusting 
trimmer, maybe heritage from the mechanical ones, laser trimming arrived 
later).
Our group became very popular and busy adjusting every watch our 
colleagues bought to a few seconds per month.


Ignacio, EB4APL


On 03/03/2013 16:29, Magnus Danielson wrote:

On 03/03/2013 03:46 PM, Jim Lux wrote:

On 3/3/13 1:00 AM, Poul-Henning Kamp wrote:

Content-Type: text/plain; charset=ISO-8859-1

In message 657D7F7CC03849419A2A90752E6A60A6@pc52, Tom Van Baak
writes:


When playing with watches a while ago I tried to pick up any 32
kHz signal but failed. Those with 1 Hz stepper motors were easy,
but LED or LCD displays were too electro/magnetic/acoustic quiet
for me to ever detect anything.


Most LCD and LED clocks have a shielding metal-coating on the front
glass, exactly to eliminate all EMI/EMC issues.



Yes, but perhaps there's enough leakage to make this work. After all,
the EMI requirement (assuming it's running at 32 kHz) isn't particularly
stringent and because the fob is small, the radiated field at any
distance is going to very small. OTOH, I can put a probe or coil right
on or around the fob.

I'll let you all know what I detect when I try it tomorrow.


An electrostatic shield will not contain the H-field from the shifting
currents.

Cheers,
Magnus
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Re: [time-nuts] FE 5860A breakout board

[EB4APL]

Geoff,

I also bought one kit from Ian, I have the doc in PDF so I can send it 
to your email address.


Regards,
Ignacio, EB4APL


On 01/03/2013 20:05, Geoff Blake wrote:

Some two years back, Ian Muir (AKA Gonzo?) produced a breakout board
for the FE 5860A, one of which I have. Needless to say, I managed to
loose (tidy away!) the documentation.

Despite searching the archives and google, I cannot find a link to
this. perhaps somebody can help.

Thanks Geoff


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Re: [time-nuts] FE-5680A DDS Board/PIC Code

[EB4APL]

Hi,

Probably Elio will jump in and tell us more on this, but I must advice 
that the unit where he did his forensic examination was a FE-5680A of 
the 10 MHz fixed frequency output  variety (not accounting for the small 
adjustment margin)and also has a fixed 1 PPS.  This unit doesn't have 
the two blue buttons and is essentially different from the 
programmable units.  Its DDS is used in a very different way and the 
PIC program should be totally different.


Regards,
Ignacio, EB4APL


On 18/02/2013 23:54, gandal...@aol.com wrote:

In a message dated 18/02/2013 22:45:12 GMT Standard Time,
paulsw...@gmail.com writes:

Herbert
Thanks for the assembly listing. Someone else on  time-nuts had done quite
the job of reverse engineering the schematics and  other information. Seems
like the two of you could collaborate. Sorry do  not recall the name.
Welcome to  time-nuts.
Regards
Paul
WB8TSL


Was just thinking the same thing so checked through my archives.


That was Elio, _eliocor@gmail.com_ (mailto:elio...@gmail.com) ,  messages
posted here about a year ago.


The messages will be in the list archives anyway but below is the text of
two messages I saved.


Regards


Nigel
GM8PZR

--

From:  elio...@gmail.com
Reply-to: time-nuts@febo.com
To:  time-nuts@febo.com
Sent: 15/02/2012 01:31:32 GMT Standard Time
Subj:  [time-nuts] FE-5680A Schematics (v0.1)


at the following  address:

http://www.rhodiatoce.com/pics/time-nuts/FE-5680A/FE-5680A_schematics_v0.1.p
df



you  will find the 0.1 release of the FE-5680A schematics.

New additions:
-  pinout of the unpopulated (24 pin) connector (J9) behind the DB9
-  connections between CPU/MAX3232 and the *TWO* serial ports!!!
- component  values of the 10MHz filter + option on PCB to output a square
10MHz wave on  DB9
- connections between CPU and MAX1246 (A/D converter)
- connections  between XC9572 and MAX392 (quad analog switch)
- unknown pins marked as  '?'

As you can see, it seems FE-5680A fully supports 2 serial  ports:
one on DB9 and the other one on the unpopulated connector (J9) behind  DB9.

Any comments/suggestions are welcome.

.   ciao
_Elio.
_



From:  elio...@gmail.com
Reply-to: time-nuts@febo.com
To:  time-nuts@febo.com
Sent: 24/02/2012 01:03:56 GMT Standard Time
Subj:  [time-nuts] FE-5680A Schematics and scans


Thanks to Ignacio (EB4APL) and the generosity of Mike  Harrison, today I
received a PCB of a disassembled FE5680A.
I provided to  make some scans of the board at 2400DPI resolution: the
picture size is about  7700x11500 pixel (9MB)

Top face (with and without  ICs):
http://www.rhodiatoce.com/pics/time-nuts/FE-5680A/FE-5680A_Top001.jpg
http://www.rhodiatoce.com/pics/time-nuts/FE-5680A/FE-5680A_Top001_noIC.jpg

Bottom  face (with and without  ICs):
http://www.rhodiatoce.com/pics/time-nuts/FE-5680A/FE-5680A_Bottom001.jpg

http://www.rhodiatoce.com/pics/time-nuts/FE-5680A/FE-5680A_Bottom001_noIC.jp
g




Being  able to remove the ICs, I was able to correct some flaws in the
previous  schematics:

http://www.rhodiatoce.com/pics/time-nuts/FE-5680A/FE-5680A_schematics_v0.2.p
df




During  the next week I will continue to write down the logical part of the
circuit  and I hope will be able to dump the 8032 firmware

_  Elio.
_

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[time-nuts] NTGS50AA Power supply

[EB4APL]

Hello,

According to a Nortel specification document (Dual Voltage Global 
Positioning System Timing Module (GPSTM) OEM General Specification
Dataset Name: GSBW50AA), this GPSDO is dual voltage and can be powered 
either from -48 V or + 24 V systems.  Mine is working from a 48 V power 
supply but I´m afraid to test it at 24 V because the polarity should be 
reversed and if my assumption is not true I can damage the unit.
Do you know if these units are dual voltage or my documentation refers 
to other model?.  Has anybody operated it at 24 V?.

Another question, is there any internal 1PPS signal available?
Of course, my unit is of ebay - China origin.

Regards,
Ignacio EB4APL
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Re: [time-nuts] NTGS50AA Power supply

[EB4APL]

Nate,

I have it already connected to a 48 V supply according to the vendor 
instructions (fluke.l is a vendor with technical knowledge)and now I 
removed the PCB from the case that I furnished and found that my unit 
doesn´t have such bridge.  Instead it have a quite elaborate reversal 
power protection (a series diode, two fuses and a pair of back connected 
diodes which will blow the fuses if the power is reversed and the first 
diode fails shorted) so I think that there are dual supply models 
(according to my documentation) and single supply ones, as my unit 
appears to be.

Thank you for the suggestion to change the 1/2PPS to 1PPS by software,
I'll try it.

Regards,
Ignacio EB4APL


El 09/02/2013 17:54, Nathaniel Bezanson wrote:


Open it up, you'll find a bridge rectifier as the first component on the 
incoming power.
It's actually much easier to solder straight to the pins of that component, 
rather than trying to bodge something together that would poke into the 
backplane connector. :)
I know there's a TSIP command for *other* units to change their PPS into PP2S 
(even second), so try throwing 8E-4E at this unit and see if you can change it 
the other way. Haven't had a chance to try it on the local one.
-Nate-
EB4APL  wrote:

 Hello,

According to a Nortel specification document (Dual Voltage Global
Positioning System Timing Module (GPSTM) OEM General Specification
Dataset Name: GSBW50AA), this GPSDO is dual voltage and can be powered
either from -48 V or + 24 V systems.  Mine is working from a 48 V power
supply but I´m afraid to test it at 24 V because the polarity should be
reversed and if my assumption is not true I can damage the unit.
Do you know if these units are dual voltage or my documentation refers
to other model?.  Has anybody operated it at 24 V?.
Another question, is there any internal 1PPS signal available?
Of course, my unit is of ebay - China origin.

Regards,
Ignacio EB4APL
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Re: [time-nuts] NTGS50AA Power supply

[EB4APL]

Bob,

Thank you for your response. I already have it working with a 48 V 
floating supply, as per the vendor info (Bob Mokia, fluke.l), but I 
found in the referred documentation that maybe I could use a 24 V power 
supply if I need it.
I bought only the PCB, not the original enclosure (too heavy) so I don't 
have any power input label.  I removed the PCB from my box, traced the 
circuit somewhat and I realized that this is not a dual voltage unit, 
but a 48 V one.  The 24 V units has the input polarity reversed on the 
same connector pins.
Have you found in your units any means of getting 1 PPS instead the 
current 1/2 PPS?


Best regards,
Ignacio EB4APL


On 09/02/2013 17:50, Bob Camp wrote:

Hi

The most common way to design this gear is with an isolated supply. That 
eliminates a bunch of odd line fault issues. The easy way to check this is with 
an ohm meter. If it's isolated (and I'll bet it is) then polarity to ground 
isn't an issue. Polarity between the supply input pins is always going to 
matter….

The back of the units I have are labeled +27V or -53V…. I run mine on a 28 
volt supply.

Bob

On Feb 9, 2013, at 11:18 AM, EB4APL eb4...@cembreros.jazztel.es wrote:


Hello,

According to a Nortel specification document (Dual Voltage Global Positioning 
System Timing Module (GPSTM) OEM General Specification
Dataset Name: GSBW50AA), this GPSDO is dual voltage and can be powered either 
from -48 V or + 24 V systems.  Mine is working from a 48 V power supply but I´m 
afraid to test it at 24 V because the polarity should be reversed and if my 
assumption is not true I can damage the unit.
Do you know if these units are dual voltage or my documentation refers to other 
model?.  Has anybody operated it at 24 V?.
Another question, is there any internal 1PPS signal available?
Of course, my unit is of ebay - China origin.

Regards,
Ignacio EB4APL
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Re: [time-nuts] NTGS50AA Power supply

[EB4APL]

Maybe I didn't explained this quite well, I'm not good writing in English.
So I try again: In the negative input first there is a forward biased 
diode, then a pair of fuses in parallel, and then the two diodes in 
series connected to the positive in the back direction, so if the input 
is reversed and the first diode became shorted, the two series connected 
diodes makes the fuses blow,(one after another or at the same time, 
giving the current involved). The diodes are schottkys and maybe they 
need two in series due to reverse voltage limits, since the 48 volts 
unit must withstand 100 V transients without failure.


Regards,
Ignacio, EB4APL


On 10/02/2013 2:17, li...@lazygranch.com wrote:

Are the two diodes really back to back? I have use two in parallel to enhance 
the time the diodes will conducting. Due to current hogging, the diodes will  
effectively turn on one at a time.

-Original Message-
From: EB4APL eb4...@cembreros.jazztel.es
Sender: time-nuts-boun...@febo.com
Date: Sun, 10 Feb 2013 02:08:17
To: Discussion of precise time and frequency measurementtime-nuts@febo.com
Reply-To: Discussion of precise time and frequency measurement
time-nuts@febo.com
Subject: Re: [time-nuts] NTGS50AA Power supply

Nate,

I have it already connected to a 48 V supply according to the vendor
instructions (fluke.l is a vendor with technical knowledge)and now I
removed the PCB from the case that I furnished and found that my unit
doesn´t have such bridge.  Instead it have a quite elaborate reversal
power protection (a series diode, two fuses and a pair of back connected
diodes which will blow the fuses if the power is reversed and the first
diode fails shorted) so I think that there are dual supply models
(according to my documentation) and single supply ones, as my unit
appears to be.
Thank you for the suggestion to change the 1/2PPS to 1PPS by software,
I'll try it.

Regards,
Ignacio EB4APL


El 09/02/2013 17:54, Nathaniel Bezanson wrote:


Open it up, you'll find a bridge rectifier as the first component on the 
incoming power.
It's actually much easier to solder straight to the pins of that component, 
rather than trying to bodge something together that would poke into the 
backplane connector. :)
I know there's a TSIP command for *other* units to change their PPS into PP2S 
(even second), so try throwing 8E-4E at this unit and see if you can change it 
the other way. Haven't had a chance to try it on the local one.
-Nate-
EB4APL  wrote:

  Hello,

According to a Nortel specification document (Dual Voltage Global
Positioning System Timing Module (GPSTM) OEM General Specification
Dataset Name: GSBW50AA), this GPSDO is dual voltage and can be powered
either from -48 V or + 24 V systems.  Mine is working from a 48 V power
supply but I´m afraid to test it at 24 V because the polarity should be
reversed and if my assumption is not true I can damage the unit.
Do you know if these units are dual voltage or my documentation refers
to other model?.  Has anybody operated it at 24 V?.
Another question, is there any internal 1PPS signal available?
Of course, my unit is of ebay - China origin.

Regards,
Ignacio EB4APL
___


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[time-nuts] Frequency satndard on ebay UK

[EB4APL]

Hi,

Has anybody in UK noticed ebay item #140845930763 ?  It reminds me the 
old Sulzer units, but longer.


Ignacio, EB4APL


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Re: [time-nuts] Shera PIC Firmware file

[EB4APL]

Hi guys,

The hex file is quite outdated.  In 2009 I contacted Brook Shera in 
order to get the source code as I wanted to build this controller and 
wanted to change the PIC to use a Flash one and add some improvements.   
His response was that he already had changed the microcontroler for a 
more modern unit, a PIC 16F876A, and included a lot of improvements.  He 
also informed me that he was not releasing the hex or source code 
anymore but he could sell me programmed PICs with the last version and 
some other components like the AD1861  at least while his supply last.  
He also supplied me the critical 74HC4046's and even the 24 MHz xtal 
oscillator.
I also ordered a board from AA Engineering and now I have to find the 
time to build it.


So I recommend you contact with Mr Shera for the last versions of this 
software.  His email has changed since the mentioned QST article and in 
2009 was: ebs(AT)mailaps.org


Best regards,
Ignacio, EB4APL



On 28/08/2012 7:30, WB6BNQ wrote:

Hi Ron,

My apologies, I got to typing and forgot to append the URL line; which is:

http://www.rt66.com/~shera/index_fs.htm

Sorry about that !  If you haven't already it is worth reading the original QST
article which he has a link to at the bottom of the page.

BillWB6BNQ


Ron Ward wrote:


Hi Bill:
I don't see the address for Shera's web page!
Thanks,
Ron

-Original Message-
From: time-nuts-boun...@febo.com [mailto:time-nuts-boun...@febo.com] On
Behalf Of WB6BNQ
Sent: Monday, August 27, 2012 3:16 PM
To: Discussion of precise time and frequency measurement
Subject: Re: [time-nuts] Shera PIC Firmware file

Ron,

Here is Mr. Shera's actual web page on the topic.  At the bottom you will
find
the HEX file file for the firmware.

Don't ask as there is no published assembly listing of the firmware.  Mr.
Shera
does not feel like releasing it to the general public at this time.

Also, on that page is a link to the original article he wrote on the
project.  So
it is a good page to bookmark.

BillWB6BNQ

Ron Ward wrote:


Hi again all:

Does anyone know where I can get a copy of Shera's PIC firmware for his
GPS-Based Frequency Standard?



Also, what enhancements are available for the latest firmware?



Thanks again,

Ron



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Re: [time-nuts] Shera PIC Firmware file

[EB4APL]

Sorry, I meant Brooks Shera.

Regards,
Ignacio, EB4APL


On 28/08/2012 23:20, EB4APL wrote:

Hi guys,

The hex file is quite outdated.  In 2009 I contacted Brook Shera in 
order to get the source code as I wanted to build this controller and 
wanted to change the PIC to use a Flash one and add some 
improvements.   His response was that he already had changed the 
microcontroler for a more modern unit, a PIC 16F876A, and included a 
lot of improvements.  He also informed me that he was not releasing 
the hex or source code anymore but he could sell me programmed PICs 
with the last version and some other components like the AD1861  at 
least while his supply last.  He also supplied me the critical 
74HC4046's and even the 24 MHz xtal oscillator.
I also ordered a board from AA Engineering and now I have to find the 
time to build it.


So I recommend you contact with Mr Shera for the last versions of this 
software.  His email has changed since the mentioned QST article and 
in 2009 was: ebs(AT)mailaps.org


Best regards,
Ignacio, EB4APL




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Re: [time-nuts] Leap second going...

[EB4APL]

I also saw (and captured a video sequence) of the leap second in 
NTGS50AA via LH, what a difference from my first encounter with the leap 
second!.
I was working in the frequency timing subsystem of a  Deep Space 
Tracking Facility when NASA decided to introduce the leap seconds, I 
don't remember it exactly but maybe we were using GMT  because until 
then, we used to offset our Cs and Rb frequency at the beginning of each 
year (did you notice the thumbwheels inside these standards?). Our first 
leap second was in Dec 31 and being this night so special the operations 
crews were given permission to leave since no any tracking activity were 
planned.   I was in a party and received a call to go to the station to 
manually introduce the leap second on the system.  Our frequency and 
timing subsystem predated the leap seconds several years so I had to set 
our redundant clock 1 second late and make a changeover between second 
00 and 01 so the second 00 was 2 seconds long.  Good old times ...


Best regards,
Ignacio, EB4APL


On 01/07/2012 2:07, Dan Rae wrote:

Just to say it did work with LH:

dr


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[time-nuts] !0 MHz standard frequency intruder

[EB4APL]

Hello,

I'm receiving, maybe from less than a  month, a new station on 10 MHz 
which claims it is an experimental time signals station.
The weird thing is that they transmit music between the minute time 
marks, heavily interfering with the other standard stations which share 
this frequency.  Currently I receive there WWV, the Italian official 
standard frequency and time station IBF and its Brazilian counterpart 
PPR (BTW PPR broadcasts local time instead of UTC). They transmit 
continuously 24 hours a day.
Every 15 minutes a female voice says that this is an experimental time 
station, gives a web page and its locator.  While I agree that anybody 
could run an standard frequency and time station, given official license 
from their local authorities (and after international coordination, I 
suppose), I think this is a truly pirate station because among their 
weird programming , I also notice:


- Their carrier is currently - 4 Hz off.
- The second ticks are offset enough to be perceived by ear with respect 
to known standards.


The transmission is in USB with full carrier (I don't have the 
designation on hand).  The format is:

- The whole sequence begins at multiples of 15 minutes.
- At second 52 they transmit something like a 2 second burst in FSK (It 
can be a fake signal without any useful information).

- At second 54 begins 1 sec ticks.
- Tick at second 59 is omitted, then only the tick for sec 0 is transmitted.
- After the 0 sec tick a male voice announces the hour and minute. The 
voice has an intonation like a news or sports speaker.
- A female voice makes an announcement about being an experimental time 
station, gives a web page and its locator.

. The ticks are discontinued and replace by music.
- The first music in a 15 minute cycle is from Peer Gynt, it is replaced 
with other music the next minutes.
- The next minutes lack the female voice announcement until next cycle 
begins.


All speaking is done in Italian language.
If I copied the locator correctly, the transmitter location is near 
Pisa, Italy.


Did anybody noticed this transmission?  I receive it in Madrid, Spain.

Regards,
Ignacio, EB4APL

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[time-nuts] Trimble/Nortel NTGS50AA GPSDO not start

[EB4APL]

Hi,

I received one of those boards from the usual Chinese supplier.  I tried 
to power it up according to the specs but the DC/DC converter doesn't start.
Tracing the power path, I find that after protective diodes and fuses, 
the -48 V line is interrupted by a power MOSFET and the question is:  is 
it necessary to make any other connections, such as strapping the 
mounting holes to a chassis, in order to make it start? Or maybe is my 
unit faulty?


TIA for your help,
Ignacio EB4APL

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Re: [time-nuts] Trimble/Nortel NTGS50AA GPSDO not start

[EB4APL]

I'm sorry but disregard my last.  I don't know what was happening before 
but it is running.

Now to connect LH and start the fun

Regards,
Ignacio, EB4APL



On 12/06/2012 2:01, EB4APL wrote:

Hi,

I received one of those boards from the usual Chinese supplier.  I 
tried to power it up according to the specs but the DC/DC converter 
doesn't start.
Tracing the power path, I find that after protective diodes and fuses, 
the -48 V line is interrupted by a power MOSFET and the question is:  
is it necessary to make any other connections, such as strapping the 
mounting holes to a chassis, in order to make it start? Or maybe is my 
unit faulty?


TIA for your help,
Ignacio EB4APL


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Re: [time-nuts] Frequency calibrator for sale ?

[EB4APL]

In contrast, the same seller tries to get $1300.0 for this coil !!!
ebay Item # 200728874248

Ignacio



El 09/06/2012 5:21, Mark Spencer escribió:

Saw what looks like a military version of a vectron frequency standard on eBay. 
 Item number

251075220188

The under $100.00 buy it now price seems a refreshing change from what others 
are asking for similar items and they are open to offers.  They probably won't 
ship to Canada and I probably have enough stuff like this so i thought I would 
pass this on.

I have no affiliation with the seller and no specific knowledge of the item in 
question.



Sent from my iPad
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Re: [time-nuts] Thunderbolt GPS rollover

[EB4APL]

Maybe you can avoid COCOM limits:  Vaisala radiosondes (the most used 
type here in Europe, see www.vaisala.com) include  half GPS receiver 
on it and the other half is in the ground tracking program.  The 
balloons go up to about 30 Km and while the speed is very low this 
height is above the limit.  Maybe you can get a recovered sonde and use 
it either directly or modulating its telemetry on your radio.  The 
receiving program SondeMonitor is licensed to amateurs by a small fee 
and can be downloaded  free for evaluation.


Ignacio, EB4APL



On 07/06/2012 5:35, Robert Watzlavick.com wrote:

Onboard gps units tend to drop out at high altitude and/or high velocities due 
to COCOM limits. Some will re-acquire at apogee but it doesn't always work.  
I'm planning for onboard telemetry but a multilateration system is the backup.

I correspond with others on aRocket and unrestricted gps units still aren't 
available to the average person without a lot of paperwork and $$$.

-Bob

On Jun 6, 2012, at 22:13, Chris Albertsonalbertson.ch...@gmail.com  wrote:


Why not fly a tiny GPS inside the rocket?  Either modulated the beacon with
the GPS serial data or record it to a micro SD card.


On Wed, Jun 6, 2012 at 7:33 PM, Robert Watzlavickroc...@watzlavick.comwrote:


Sorry to resurrect an old thread but I also have a question about using
the Thunderbolt in the future.  I'm considering using 4 of them in a
multilateration setup to track an amateur rocket with an onboard beacon.

Chris Albertson
Redondo Beach, California
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Re: [time-nuts] NTGS50AA, better than Thunderbolt

[EB4APL]

Well, I don't understand well what is happening.  Unless I am totally 
wrong and bought a piece of crap, I still see  $25 as the standard 
international shipping.  I just bought one.


Ignacio, EB4APL



On 03/05/2012 22:33, Steve wrote:

Guess I waited too long to order. $60 for shipping - I'll pass.

Steve



On May 3, 2012, at 3:16 PM, Dan Raedan...@verizon.net  wrote:


On 5/3/2012 1:08 PM, Steve wrote:

Did the seller double the shipping cost today? I could have sworn it was $30 the
last time I looked at the listing.

Steve


Yes, he did.  Unfortunately I didn't check since I still had the page open from 
earlier, and didn't find out till I went to Paypal...

He certainly isn't getting positive feedback from me.

Dan

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Re: [time-nuts] Best location for a GPS antenna...?

[EB4APL]

Hi,

I have a personal reference:  In the Deep Space tracking facility where 
I used to work some 20 years ago it was very common to have 
minicomputers damaged by strikes in the antenna.  This antenna was 
located about 1000' from the control room and there were an elaborate 
grounding system both in the antenna (mainly intended to protect from 
lightning) and in the control room, but we got TTL chips damaged very 
often during thunderstorms.  The common believe was the high currents 
induced in the ground cabling caused  voltage spikes inside the computer 
cabinets enough to fry the chips.  I don't remember failures in the 
receivers, transmitters or other subsystems, but minicomputers were the 
usual targets, one or two chips each time.


Regards,
Ignacio, EB4APL


On 12/04/2012 23:21, Bob Camp wrote:

Hi

Do you have a reference for 100' distant strikes routinely destroying
receivers?

Bob

-Original Message-
From: time-nuts-boun...@febo.com [mailto:time-nuts-boun...@febo.com] On
Behalf Of Chris Albertson
Sent: Thursday, April 12, 2012 3:25 PM
To: Discussion of precise time and frequency measurement
Subject: Re: [time-nuts] Best location for a GPS antenna...?

On Thu, Apr 12, 2012 at 11:56 AM, Randy D. Hunt
randy_hunt...@yahoo.comwrote:


On 4/12/2012 1:10 AM, Heinzmann, Stefan (ALC NetworX GmbH) wrote:


What about mounting the antenna on the side of the metal pole, with the
top of the pole extending a foot or more above the antenna?



Typically when a receiver or other radio is destroyed it was NOT because of
a direct strike.  A strike within maybe 100 feet is enough.  There is a
_huge_ EMP field around the strike.  The field will induce large currents
in any nearby conductors.   Even if the strike is to bare Earth many feet
from the antenna the potential of the earth is raised by say 1,000 volts so
now anything connected between ground the power has 1KV across it.





Chris Albertson
Redondo Beach, California
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