Re: [time-nuts] Lady Heather numbers

[Bob Camp]

Hi

The temperature of your TBolt is moving 2.5 C. The OCXO frequency directly
follows this temperature. The OCXO is likely moving 3 ppb as the temperature
changes by 2.5C. That drives the PPS back and forth.

Put another way - most of what you see is related to the problem with the
OCXO and it's lack of a proper oven.

Bob

-Original Message-
From: time-nuts-boun...@febo.com [mailto:time-nuts-boun...@febo.com] On
Behalf Of Garren Davis
Sent: Wednesday, February 27, 2013 10:27 AM
To: Discussion of precise time and frequency measurement
Subject: Re: [time-nuts] Lady Heather numbers


Warren,

Thanks for the comments. I've included a 34 hour screen dump. Trying to
understand why
the PPS trace is doing what it is doing. Looks like it might have something
to do with
the temperature.

I'm going to try a different GPS antenna and mount it higher this weekend.
I'll do a 24 hour
survey and start another run. After that I'll try a different power supply.
Right now I'm
using a PC power supply. It's probably a bit noisy.

Garren


-Original Message-
From: time-nuts-boun...@febo.com [mailto:time-nuts-boun...@febo.com] On
Behalf Of WarrenS
Sent: Tuesday, February 26, 2013 10:53 AM
To: Discussion of precise time and frequency measurement
Subject: Re: [time-nuts] Lady Heather numbers

>Can anyone comment on the picture.
>I don't know if what I have would be considered good as far as accuracy
>and stability is concerned.

The screen dump is way too short to give much detail.
What can be said from what is there:
>From a Ham standpoint it is all working fine and is much better than 1e-9.

>From a time nut standpoint it is very poor.
It is using the default setting (for the most part) Phase error at -100ns is
~50 times high for the 100 sec TC setting used, (likely due to the high
drift rate of the Osc) Frequency error is wondering around 1e-10 is about 50
times higher than what is possible.
Effect on freq and phase noise with sat changes is >>10 times more that what
is possible with good setup.

Concerning your Dac comments, Yes makes sense, but your conclusing is wrong.
Can't say or sure, because the 24 Hr + screen shot is not shown, but in
general The Tbolt temperature reading has no direct effect on the Dac
control voltage unless the Tbolt is in hold over.
The Dac voltage changes because the oscillator's freq is trying to change,
not the other way around.
You can disable the Dac from changing with "dd".

ws


From: "Garren Davis"
Subject: [time-nuts] Lady Heather numbers

Hi,

I have been playing with my thunderbolt and Lady Heather over the weekend. I
hope it's ok
that I attached a screen dump of what I have. Can anyone comment on the
picture. It's been
running less than a day and I don't know if what I have would be considered
good as far as
accuracy and stability is concerned.
Thanks.
Garren

**
Garren Davis garren.davis at qlogic.com

>From looking at the graph over 24 hours it looks like the outer oven varies
>about +-.5C. This is
from the tbolt temperature sensor as the tbolt is in the outer oven. The
inner oven where the
oscillator is located holds at 66.4C. My concern is that it looks like the
tbolt algorithm controls
the DAC voltage depending on the temperature that the tbolt reads.
Temperature goes up, the DAC
voltage goes up. If the inner oven is holding steady then I don't want the
DAC voltage changing
if the temperature in the outer oven is changing. Is there any way to tell
the tbolt algorithm to
ignore the temperature in its DAC calculation?

Wow, I hope this makes sense the way I explained it.

Garren




8

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[time-nuts] Advise on HP-5335a features

[Paul Berger]

I am considering getting a counter with better resolution than my 5316A, 
and have been looking at 5335A, they seem to be quite capable and fit my 
budget, but I have some questions about options.


1. How useful is the option 020 DC voltmeter?  Does it offer good 
resolution?
2. Is the option 040 a desirable feature?  Will it improve the 
performance of the counter?  or would I be better off getting one with 
the OXCO feature?


I also looked at a 5370A that was in my price range however the seller 
would only ship by UPS and the cost of shipping was as much as the 5370A 
even before UPS skins me for bringing it across the border, all the 
other 5370s where out of reach.

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Re: [time-nuts] Lady Heather numbers

[Garren Davis]

I don't doubt that my oven could be the problem but I would think a lot of 
people have their tbolts sitting in a room or basement with a lot more 
temperature swing than 2.5C. I also monitor the inner oven temperature where 
the oscillator is located and it remains stable at 67C regardless of the 2.5C 
swing of the outer oven. This makes me wonder if the tbolt temperature is used 
in the algorithm that steers the osc frequency. I'll have to try some 
experiments to see if I can figure this out.

Thanks for the feedback Bob.

Garren


-Original Message-
From: time-nuts-boun...@febo.com [mailto:time-nuts-boun...@febo.com] On Behalf 
Of Bob Camp
Sent: Wednesday, February 27, 2013 9:49 AM
To: 'Discussion of precise time and frequency measurement'
Subject: Re: [time-nuts] Lady Heather numbers

Hi

The temperature of your TBolt is moving 2.5 C. The OCXO frequency directly 
follows this temperature. The OCXO is likely moving 3 ppb as the temperature 
changes by 2.5C. That drives the PPS back and forth.

Put another way - most of what you see is related to the problem with the OCXO 
and it's lack of a proper oven.

Bob

-Original Message-
From: time-nuts-boun...@febo.com [mailto:time-nuts-boun...@febo.com] On Behalf 
Of Garren Davis
Sent: Wednesday, February 27, 2013 10:27 AM
To: Discussion of precise time and frequency measurement
Subject: Re: [time-nuts] Lady Heather numbers


Warren,

Thanks for the comments. I've included a 34 hour screen dump. Trying to 
understand why the PPS trace is doing what it is doing. Looks like it might 
have something to do with the temperature.

I'm going to try a different GPS antenna and mount it higher this weekend.
I'll do a 24 hour
survey and start another run. After that I'll try a different power supply.
Right now I'm
using a PC power supply. It's probably a bit noisy.

Garren


-Original Message-
From: time-nuts-boun...@febo.com [mailto:time-nuts-boun...@febo.com] On Behalf 
Of WarrenS
Sent: Tuesday, February 26, 2013 10:53 AM
To: Discussion of precise time and frequency measurement
Subject: Re: [time-nuts] Lady Heather numbers

>Can anyone comment on the picture.
>I don't know if what I have would be considered good as far as accuracy
>and stability is concerned.

The screen dump is way too short to give much detail.
What can be said from what is there:
>From a Ham standpoint it is all working fine and is much better than 1e-9.

>From a time nut standpoint it is very poor.
It is using the default setting (for the most part) Phase error at -100ns is
~50 times high for the 100 sec TC setting used, (likely due to the high drift 
rate of the Osc) Frequency error is wondering around 1e-10 is about 50 times 
higher than what is possible.
Effect on freq and phase noise with sat changes is >>10 times more that what is 
possible with good setup.

Concerning your Dac comments, Yes makes sense, but your conclusing is wrong.
Can't say or sure, because the 24 Hr + screen shot is not shown, but in general 
The Tbolt temperature reading has no direct effect on the Dac control voltage 
unless the Tbolt is in hold over.
The Dac voltage changes because the oscillator's freq is trying to change, not 
the other way around.
You can disable the Dac from changing with "dd".

ws


From: "Garren Davis"
Subject: [time-nuts] Lady Heather numbers

Hi,

I have been playing with my thunderbolt and Lady Heather over the weekend. I 
hope it's ok that I attached a screen dump of what I have. Can anyone comment 
on the picture. It's been running less than a day and I don't know if what I 
have would be considered good as far as accuracy and stability is concerned.
Thanks.
Garren

**
Garren Davis garren.davis at qlogic.com

>From looking at the graph over 24 hours it looks like the outer oven
>varies about +-.5C. This is
from the tbolt temperature sensor as the tbolt is in the outer oven. The inner 
oven where the oscillator is located holds at 66.4C. My concern is that it 
looks like the tbolt algorithm controls the DAC voltage depending on the 
temperature that the tbolt reads.
Temperature goes up, the DAC
voltage goes up. If the inner oven is holding steady then I don't want the DAC 
voltage changing if the temperature in the outer oven is changing. Is there any 
way to tell the tbolt algorithm to ignore the temperature in its DAC 
calculation?

Wow, I hope this makes sense the way I explained it.

Garren




8

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Re: [time-nuts] Lady Heather numbers

[WarrenS]

Garren

The 34 hr plot helps a lot to see what is going on.
First off let me say what you have is working fine for most any real 
application,
but if you want to be extreme time nuts, there are lots of improvements that 
can be made.

In no special order.

1) Signal level is about 10 dBc lower than ideal, It is not much of an issue 
until other things have been improved.


2) The Dac Gain is still at the default of -5.0 Hz /V,  Best to 'calibrate" 
that. Again not a big deal yet.


3) The Damping is at the default 1.2, changing that to ~0.8 will reduced the 
Phase error considerably


4) The default TC setting (Time Constant) of 100 sec is about right for now,
but later if you fix the Osc tempco issue,  you'll improve things by 
changing that to ~ 300 sec

(If you just changed the TC from 100 to 300 now it would make things worse)

5) change the ADEV data plot to a "SAS" antenna survey plot to make sure 
there are no blind spots or multipath signals
The SAS plot will help tell where your EL and AMU should be set. ( they are 
set OK for now)
5a) The average sat count of 6  with a low of 4 shows your antenna has a 
good basic view of the sky. (no problem there)


6) your Holdover is still at 0 seconds, This is good, it means you never go 
into hold over.


7) Dac voltage at -.6xx is fine and seems to of stabilized well from your 
first plot that had a lot of initial turn-on drifting.


8) main problem and the first thing to improve, is the Oscillators tempco 
sensitivity.
To better see it, manually change the gain and offset of the Temp plot, and 
you will see how well it lines up with the Dac plot.

Trying to understand why the PPS trace is doing what it is doing.
Looks like it might have something to do with the temperature.
Correct, The PPS is doing what it is doing because it is tracking the slope 
of the DAC which in turn is directly tracking the Temp change of the sensor.
Several ways to help it, how you do that with your dual temp control will be 
a nice learning experience.

bottom line is:
Don't let the temp change so much.  and/or
make the Osc less sensitive to the temp change


other setup hints
a) Helps if something goes wrong if you turn on "Log" so you do not loose 
the plot info.
b) set the display Q to 30 days, so you can compare the before and after 
effects of any change you do, all on screen at the same time.
c) turn off the ADEV plots and data display, They are not adding any useful 
info at this time.



Have fun
ws

*
Garren Davis posted:
Warren,

Thanks for the comments. I've included a 34 hour screen dump. Trying to 
understand why
the PPS trace is doing what it is doing. Looks like it might have something 
to do with

the temperature.

I'm going to try a different GPS antenna and mount it higher this weekend. 
I'll do a 24 hour
survey and start another run. After that I'll try a different power supply. 
Right now I'm

using a PC power supply. It's probably a bit noisy.

Garren


-Original Message-
From: time-nuts-bounces at febo.com [mailto:time-nuts-bounces at febo.com] 
On Behalf Of WarrenS

Sent: Tuesday, February 26, 2013 10:53 AM
To: Discussion of precise time and frequency measurement
Subject: Re: [time-nuts] Lady Heather numbers


Can anyone comment on the picture.
I don't know if what I have would be considered good as far as accuracy
and stability is concerned.


The screen dump is way too short to give much detail.
What can be said from what is there:

From a Ham standpoint it is all working fine and is much better than 1e-9.



From a time nut standpoint it is very poor.
It is using the default setting (for the most part) Phase error at -100ns is 
~50 times high for the 100 sec TC setting used, (likely due to the high 
drift rate of the Osc) Frequency error is wondering around 1e-10 is about 50 
times higher than what is possible.
Effect on freq and phase noise with sat changes is >>10 times more that what 
is possible with good setup.


Concerning your Dac comments, Yes makes sense, but your conclusing is wrong.
Can't say or sure, because the 24 Hr + screen shot is not shown, but in 
general The Tbolt temperature reading has no direct effect on the Dac 
control voltage unless the Tbolt is in hold over.
The Dac voltage changes because the oscillator's freq is trying to change, 
not the other way around.

You can disable the Dac from changing with "dd".

ws


From: "Garren Davis"
Subject: [time-nuts] Lady Heather numbers

Hi,

I have been playing with my thunderbolt and Lady Heather over the weekend. I
hope it's ok
that I attached a screen dump of what I have. Can anyone comment on the
picture. It's been
running less than a day and I don't know if what I have would be considered
good as far as
accuracy and stability is concerned.
Thanks.
Garren

**
Garren Davis garren.davis at qlogic.com


From looking at the graph over 24 hours it looks like the outer oven varies
about +-.5C. This is

from the tbo

[time-nuts] Lady Heather numbers

[Arthur Dent]

There has been a lot of speculation about the innards of the OXCO in the
Thunderbolt so here is what I found inside a dead one that I opened. I
didn’t trace the circuit out so most of the description that follows is just
from a cursory look and may not be totally correct. Below are links to a
couple of photos of the oscillator board.

The OXCO in the Thunderbolt (Trimble 37265) is a single oven unit. The
circuit board is mounted on the connection pins and has fiberglass mats
on top and bottom for thermal isolation. There are two +12VDC input
pins, one for the oven and the other for the oscillator power. The +12V
pin for the oscillator goes through a 1 ohm resistor to a 8L08A 8V three-
terminal linear regulator which powers the oscillator and most of the other
electronics. The ‘heater’ that is powered by a separate +12V pin is a
2N4921 transistor mounted on the copper block with the crystal and the
thermistor. There is a diode between the input pin and the transistor for
reverse polarity protection but not on the oscillator input pin. From reading
some of the past post about people connecting the power to the Tbolt
incorrectly, this would explain why the heater still works but there is no
output. The 1 ohm and/or the 8L08A are destroyed while the heater circuit
was protected. Other stuff on the Tbolt board probably gets destroyed as
well.

The crystal is marked OFCG-P, Div of Oak Ind and this one is marked 86.3C
for the temperature. The oven controller is an LM358 dual OP-AMP and there
is a 10-turn pot that I believe sets the oven temp. It looks like the 10Mhz
output goes through a couple of transistors, a transformer, and some L-C stuff
before going to the output pin. There is a SOD-323 device marked VD1 which
may be a BB639 varactor for the EFC adjustment.

-Arthur 

http://i906.photobucket.com/albums/ac262/rjb1998/OXCOinside1_zps02c43ce6.jpg
http://i906.photobucket.com/albums/ac262/rjb1998/OXCOinside2_zps2b758675.jpg
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Re: [time-nuts] Lady Heather numbers

[Bob Camp]

Hi

The TBolt does not use the temperature monitor when in locked mode. Your
OCXO is changing temperature. Roughly a 0.008 C temperature change would
explain the movement you see.

Bob

-Original Message-
From: time-nuts-boun...@febo.com [mailto:time-nuts-boun...@febo.com] On
Behalf Of Garren Davis
Sent: Wednesday, February 27, 2013 1:20 PM
To: Discussion of precise time and frequency measurement
Subject: Re: [time-nuts] Lady Heather numbers


I don't doubt that my oven could be the problem but I would think a lot of
people have their tbolts sitting in a room or basement with a lot more
temperature swing than 2.5C. I also monitor the inner oven temperature where
the oscillator is located and it remains stable at 67C regardless of the
2.5C swing of the outer oven. This makes me wonder if the tbolt temperature
is used in the algorithm that steers the osc frequency. I'll have to try
some experiments to see if I can figure this out.

Thanks for the feedback Bob.

Garren


-Original Message-
From: time-nuts-boun...@febo.com [mailto:time-nuts-boun...@febo.com] On
Behalf Of Bob Camp
Sent: Wednesday, February 27, 2013 9:49 AM
To: 'Discussion of precise time and frequency measurement'
Subject: Re: [time-nuts] Lady Heather numbers

Hi

The temperature of your TBolt is moving 2.5 C. The OCXO frequency directly
follows this temperature. The OCXO is likely moving 3 ppb as the temperature
changes by 2.5C. That drives the PPS back and forth.

Put another way - most of what you see is related to the problem with the
OCXO and it's lack of a proper oven.

Bob

-Original Message-
From: time-nuts-boun...@febo.com [mailto:time-nuts-boun...@febo.com] On
Behalf Of Garren Davis
Sent: Wednesday, February 27, 2013 10:27 AM
To: Discussion of precise time and frequency measurement
Subject: Re: [time-nuts] Lady Heather numbers


Warren,

Thanks for the comments. I've included a 34 hour screen dump. Trying to
understand why the PPS trace is doing what it is doing. Looks like it might
have something to do with the temperature.

I'm going to try a different GPS antenna and mount it higher this weekend.
I'll do a 24 hour
survey and start another run. After that I'll try a different power supply.
Right now I'm
using a PC power supply. It's probably a bit noisy.

Garren


-Original Message-
From: time-nuts-boun...@febo.com [mailto:time-nuts-boun...@febo.com] On
Behalf Of WarrenS
Sent: Tuesday, February 26, 2013 10:53 AM
To: Discussion of precise time and frequency measurement
Subject: Re: [time-nuts] Lady Heather numbers

>Can anyone comment on the picture.
>I don't know if what I have would be considered good as far as accuracy
>and stability is concerned.

The screen dump is way too short to give much detail.
What can be said from what is there:
>From a Ham standpoint it is all working fine and is much better than 1e-9.

>From a time nut standpoint it is very poor.
It is using the default setting (for the most part) Phase error at -100ns is
~50 times high for the 100 sec TC setting used, (likely due to the high
drift rate of the Osc) Frequency error is wondering around 1e-10 is about 50
times higher than what is possible.
Effect on freq and phase noise with sat changes is >>10 times more that what
is possible with good setup.

Concerning your Dac comments, Yes makes sense, but your conclusing is wrong.
Can't say or sure, because the 24 Hr + screen shot is not shown, but in
general The Tbolt temperature reading has no direct effect on the Dac
control voltage unless the Tbolt is in hold over.
The Dac voltage changes because the oscillator's freq is trying to change,
not the other way around.
You can disable the Dac from changing with "dd".

ws


From: "Garren Davis"
Subject: [time-nuts] Lady Heather numbers

Hi,

I have been playing with my thunderbolt and Lady Heather over the weekend. I
hope it's ok that I attached a screen dump of what I have. Can anyone
comment on the picture. It's been running less than a day and I don't know
if what I have would be considered good as far as accuracy and stability is
concerned.
Thanks.
Garren

**
Garren Davis garren.davis at qlogic.com

>From looking at the graph over 24 hours it looks like the outer oven
>varies about +-.5C. This is
from the tbolt temperature sensor as the tbolt is in the outer oven. The
inner oven where the oscillator is located holds at 66.4C. My concern is
that it looks like the tbolt algorithm controls the DAC voltage depending on
the temperature that the tbolt reads.
Temperature goes up, the DAC
voltage goes up. If the inner oven is holding steady then I don't want the
DAC voltage changing if the temperature in the outer oven is changing. Is
there any way to tell the tbolt algorithm to ignore the temperature in its
DAC calculation?

Wow, I hope this makes sense the way I explained it.

Garren




8

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[time-nuts] Newbie question about thunderbolts

[Paul Berger]

Hello all:

I am an electronic technician with 30+ years experience fixing
computers.   In my spare time I like to play with old computers and
electronics.  Recently I got bit by the precision timing bug, partially
after running across the wonderful leapsecond.com site, which lead me
here.   First I got  a FE-5680A, then after reading some of the archives
here I bought a Nortel / Trimble 45000   GPSDO and still later a used
Thunderbolt-E.

My main interest in these devices at this time is for a accurate bench
top frequency source, however I do have a 59309A running off of each of
the GPSDOs.  I am wondering if they will drift apart, but I suspect I
will need to wait a long time to see evidence of that. I set them
simultaneously by setting them both to the same GPIB address and
connecting them to the same bus on my HP-86B, this works well for
setting them but I have to remember to disconnect one or change the
address on one before I try to read them.

MY question concerns the thunderbolt-E, I have been using LH to monitor
both of the GPSDOs and was quite surprised to see that the Nortel 45000
seems to perform much better than the thunderbolt-E, I thought that the
E being a newer device it would perform better.  I will admit that I
have a much less than ideal antenna setup however the antenna location
is the same for both devices, they are  only a couple feet apart.  The
antenna's are a Trimble magnet mount antenna and a the dome antenna that
came with the thunderbolt-E kit. Initially I had the magnet mount
attached to the Nortel and the dome antenna attached to the E, but I
have now swapped antennas but it has not made any difference , and I am
beginning to wonder if my E is in fact defective.  I have been in
contact with one other person who has an E and his experiences have been
similar to mine, even though he has a much better antenna setup, so I
would like to ask if there is anyone else out there with an E, and ask
the group for comments on what I am seeing.

My observations have been that the 10MHz is not very stable, on LH I
will see relatively large spikes  in the DAC voltage that of course
impacts the 10MHZ, I had it connected to my 5316A counter that was
running with the FE-5680A as a timebase, with a 10 second gate time and
logging counts with my 86B and I was seeing excursions og over 100Hz
which I guess percentage wise is not huge but I do not see anything like
that on the Nortel.  Now some of these excursions do occur when there
are satellite switches, and if they all occurred coincident to satellite
switches I would mark it up to my crummy antenna arrangement, but they
don't they occur even when the satellite tracking is stable and often
come in groups of several transition first positive followed by an equal
transition in the negative direction. There is also a constant
chatter of about 100uV on the DAC line as reported by LH which also
translates to noise on the OSC and PPS lines, my technician sense thinks
that looks like power supply noise, but I have not looked under the hood
yet.   One really annoying thing I have noticed is the E reports having
saved my location, however it apparently has not so every time it resets
for whatever reason it goes into a self survey, which because of my less
than ideal antenna setup usually takes some time to complete, even a
warm reset resulted in it losing it location and entering self survey.



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Re: [time-nuts] Lady Heather numbers

[Charles P. Steinmetz]

Garren wrote:

I don't doubt that my oven could be the problem but I would think a 
lot of people have their tbolts sitting in a room or basement with a 
lot more temperature swing than 2.5C. I also monitor the inner oven 
temperature where the oscillator is located and it remains stable at 
67C regardless of the 2.5C swing of the outer oven. This makes me 
wonder if the tbolt temperature is used in the algorithm that steers 
the osc frequency. I'll have to try some experiments to see if I can 
figure this out.


What you see is the GPS discipline doing its job.

As others have said, the temperature reported by the Thunderbolt's 
internal sensor is not used by the Tbolt during locked operation (you 
can find lots of posts on this subject in the archives).  Note that 
your white oscillator trace sits stably on frequency (at time scales 
comparable to the temperature changes).  This is because the Tbolt 
control loop is counteracting the temperature drift of the crystal.


If the crystal frequency was not varying with temperature but the 
Tbolt was running the DAC up and down in response to the internal 
temperature sensor (as you posit), you would expect to see the white 
oscillator trace tracking the temperature and DAC traces as the 
oscillator was erroneously forced off frequency by the control loop.


Best regards,

Charles




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Re: [time-nuts] Advise on HP-5335a features

[Robert Darlington]

These are nice counters, but they're slow.  My 5335A takes ~ 6 seconds to
do a full resolution measurement.

-Bob


On Wed, Feb 27, 2013 at 11:09 AM, Paul Berger  wrote:

> I am considering getting a counter with better resolution than my 5316A,
> and have been looking at 5335A, they seem to be quite capable and fit my
> budget, but I have some questions about options.
>
> 1. How useful is the option 020 DC voltmeter?  Does it offer good
> resolution?
> 2. Is the option 040 a desirable feature?  Will it improve the performance
> of the counter?  or would I be better off getting one with the OXCO feature?
>
> I also looked at a 5370A that was in my price range however the seller
> would only ship by UPS and the cost of shipping was as much as the 5370A
> even before UPS skins me for bringing it across the border, all the other
> 5370s where out of reach.
> __**_
> time-nuts mailing list -- time-nuts@febo.com
> To unsubscribe, go to https://www.febo.com/cgi-bin/**
> mailman/listinfo/time-nuts
> and follow the instructions there.
>
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Re: [time-nuts] Lady Heather numbers

[Garren Davis]

Opps, Now your confusing me. You say the tbolt does not use the temperature 
monitor when in locked mode. In your previous message you said "The temperature 
of your TBolt is moving 2.5 C. The OCXO frequency directly follows this 
temperature". Do you mean the inner oven is changing .008C because of the 2.5C 
change in the outer oven?
I'll back away from all the questions for a while and study this a bit. 
Probably move some thermistors to different locations.

It is fun trying different things and seeing what happens.

Garren

-Original Message-
From: time-nuts-boun...@febo.com [mailto:time-nuts-boun...@febo.com] On Behalf 
Of Bob Camp
Sent: Wednesday, February 27, 2013 12:12 PM
To: 'Discussion of precise time and frequency measurement'
Subject: Re: [time-nuts] Lady Heather numbers

Hi

The TBolt does not use the temperature monitor when in locked mode. Your OCXO 
is changing temperature. Roughly a 0.008 C temperature change would explain the 
movement you see.

Bob

-Original Message-
From: time-nuts-boun...@febo.com [mailto:time-nuts-boun...@febo.com] On Behalf 
Of Garren Davis
Sent: Wednesday, February 27, 2013 1:20 PM
To: Discussion of precise time and frequency measurement
Subject: Re: [time-nuts] Lady Heather numbers


I don't doubt that my oven could be the problem but I would think a lot of 
people have their tbolts sitting in a room or basement with a lot more 
temperature swing than 2.5C. I also monitor the inner oven temperature where 
the oscillator is located and it remains stable at 67C regardless of the 2.5C 
swing of the outer oven. This makes me wonder if the tbolt temperature is used 
in the algorithm that steers the osc frequency. I'll have to try some 
experiments to see if I can figure this out.

Thanks for the feedback Bob.

Garren


-Original Message-
From: time-nuts-boun...@febo.com [mailto:time-nuts-boun...@febo.com] On Behalf 
Of Bob Camp
Sent: Wednesday, February 27, 2013 9:49 AM
To: 'Discussion of precise time and frequency measurement'
Subject: Re: [time-nuts] Lady Heather numbers

Hi

The temperature of your TBolt is moving 2.5 C. The OCXO frequency directly 
follows this temperature. The OCXO is likely moving 3 ppb as the temperature 
changes by 2.5C. That drives the PPS back and forth.

Put another way - most of what you see is related to the problem with the OCXO 
and it's lack of a proper oven.

Bob

-Original Message-
From: time-nuts-boun...@febo.com [mailto:time-nuts-boun...@febo.com] On Behalf 
Of Garren Davis
Sent: Wednesday, February 27, 2013 10:27 AM
To: Discussion of precise time and frequency measurement
Subject: Re: [time-nuts] Lady Heather numbers


Warren,

Thanks for the comments. I've included a 34 hour screen dump. Trying to 
understand why the PPS trace is doing what it is doing. Looks like it might 
have something to do with the temperature.

I'm going to try a different GPS antenna and mount it higher this weekend.
I'll do a 24 hour
survey and start another run. After that I'll try a different power supply.
Right now I'm
using a PC power supply. It's probably a bit noisy.

Garren


-Original Message-
From: time-nuts-boun...@febo.com [mailto:time-nuts-boun...@febo.com] On Behalf 
Of WarrenS
Sent: Tuesday, February 26, 2013 10:53 AM
To: Discussion of precise time and frequency measurement
Subject: Re: [time-nuts] Lady Heather numbers

>Can anyone comment on the picture.
>I don't know if what I have would be considered good as far as accuracy
>and stability is concerned.

The screen dump is way too short to give much detail.
What can be said from what is there:
>From a Ham standpoint it is all working fine and is much better than 1e-9.

>From a time nut standpoint it is very poor.
It is using the default setting (for the most part) Phase error at -100ns is
~50 times high for the 100 sec TC setting used, (likely due to the high drift 
rate of the Osc) Frequency error is wondering around 1e-10 is about 50 times 
higher than what is possible.
Effect on freq and phase noise with sat changes is >>10 times more that what is 
possible with good setup.

Concerning your Dac comments, Yes makes sense, but your conclusing is wrong.
Can't say or sure, because the 24 Hr + screen shot is not shown, but in general 
The Tbolt temperature reading has no direct effect on the Dac control voltage 
unless the Tbolt is in hold over.
The Dac voltage changes because the oscillator's freq is trying to change, not 
the other way around.
You can disable the Dac from changing with "dd".

ws


From: "Garren Davis"
Subject: [time-nuts] Lady Heather numbers

Hi,

I have been playing with my thunderbolt and Lady Heather over the weekend. I 
hope it's ok that I attached a screen dump of what I have. Can anyone comment 
on the picture. It's been running less than a day and I don't know if what I 
have would be considered good as far as accuracy and stability is concerned.
Thanks.
Garren

**
Garren Davis garr

Re: [time-nuts] time-nuts Digest, Vol 103, Issue 87

[Russ Ramirez]

Hi Paul, I recently purchased a very clean 5334B, which I then decided to
drive with a Thunderbolt GPSDO, thanks to input from this community,
because I wanted accuracy to the least significant digit. The OCXO in the
5334B was off by 13 Hz (know that now, not then) but for the price of a
Thunderbolt, you get the extra accuracy and the 10 MHz reference for other
equipment. I think any of the models in the 53xx series are fine pieces of
equipment, and possess a level of input sensitivity that most sub
$500 frequency counters cannot touch. I was not concerned about the
voltmeter option the 5335 in my case because I already had a Boonton RF
millivoltmeter.

Russ
K0WFS

--

Message: 2
Date: Wed, 27 Feb 2013 14:09:44 -0400
From: Paul Berger 
To: time-nuts@febo.com
Subject: [time-nuts] Advise on HP-5335a features
Message-ID: <512e4be8.3030...@gmail.com>
Content-Type: text/plain; charset=ISO-8859-1; format=flowed

I am considering getting a counter with better resolution than my 5316A,
and have been looking at 5335A, they seem to be quite capable and fit my
budget, but I have some questions about options.

1. How useful is the option 020 DC voltmeter?  Does it offer good
resolution?
2. Is the option 040 a desirable feature?  Will it improve the
performance of the counter?  or would I be better off getting one with
the OXCO feature?

I also looked at a 5370A that was in my price range however the seller
would only ship by UPS and the cost of shipping was as much as the 5370A
even before UPS skins me for bringing it across the border, all the
other 5370s where out of reach.
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Re: [time-nuts] Newbie question about thunderbolts

[James Tucker]

Hi, Paul. Glad to see you made it here. For the time-nuts; Paul and I
have spoken about these issues, and I have had similar experience. The
only thing I would add is the the spikes to seem to occur less
frequently with a better antenna placement, but when they start to
cluster, they fire off one every two or three seconds, sometimes
faster.

JimT

On Wed, Feb 27, 2013 at 2:08 PM, Paul Berger  wrote:
>
> Hello all:
>
> I am an electronic technician with 30+ years experience fixing
> computers.   In my spare time I like to play with old computers and
> electronics.  Recently I got bit by the precision timing bug, partially
> after running across the wonderful leapsecond.com site, which lead me
> here.   First I got  a FE-5680A, then after reading some of the archives
> here I bought a Nortel / Trimble 45000   GPSDO and still later a used
> Thunderbolt-E.
>
> My main interest in these devices at this time is for a accurate bench
> top frequency source, however I do have a 59309A running off of each of
> the GPSDOs.  I am wondering if they will drift apart, but I suspect I
> will need to wait a long time to see evidence of that. I set them
> simultaneously by setting them both to the same GPIB address and
> connecting them to the same bus on my HP-86B, this works well for
> setting them but I have to remember to disconnect one or change the
> address on one before I try to read them.
>
> MY question concerns the thunderbolt-E, I have been using LH to monitor
> both of the GPSDOs and was quite surprised to see that the Nortel 45000
> seems to perform much better than the thunderbolt-E, I thought that the
> E being a newer device it would perform better.  I will admit that I
> have a much less than ideal antenna setup however the antenna location
> is the same for both devices, they are  only a couple feet apart.  The
> antenna's are a Trimble magnet mount antenna and a the dome antenna that
> came with the thunderbolt-E kit. Initially I had the magnet mount
> attached to the Nortel and the dome antenna attached to the E, but I
> have now swapped antennas but it has not made any difference , and I am
> beginning to wonder if my E is in fact defective.  I have been in
> contact with one other person who has an E and his experiences have been
> similar to mine, even though he has a much better antenna setup, so I
> would like to ask if there is anyone else out there with an E, and ask
> the group for comments on what I am seeing.
>
> My observations have been that the 10MHz is not very stable, on LH I
> will see relatively large spikes  in the DAC voltage that of course
> impacts the 10MHZ, I had it connected to my 5316A counter that was
> running with the FE-5680A as a timebase, with a 10 second gate time and
> logging counts with my 86B and I was seeing excursions og over 100Hz
> which I guess percentage wise is not huge but I do not see anything like
> that on the Nortel.  Now some of these excursions do occur when there
> are satellite switches, and if they all occurred coincident to satellite
> switches I would mark it up to my crummy antenna arrangement, but they
> don't they occur even when the satellite tracking is stable and often
> come in groups of several transition first positive followed by an equal
> transition in the negative direction. There is also a constant
> chatter of about 100uV on the DAC line as reported by LH which also
> translates to noise on the OSC and PPS lines, my technician sense thinks
> that looks like power supply noise, but I have not looked under the hood
> yet.   One really annoying thing I have noticed is the E reports having
> saved my location, however it apparently has not so every time it resets
> for whatever reason it goes into a self survey, which because of my less
> than ideal antenna setup usually takes some time to complete, even a
> warm reset resulted in it losing it location and entering self survey.
>
>
>
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[time-nuts] cesium for sale - you know where

[Chris Howard]

I've decided to list my FTS-4060 on ebay, item# 151004036331
No reserve, 10 days.

Notices tacked on the local telephone poles just have not
resulted in much interest.

Chris




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Re: [time-nuts] cesium for sale - you know where

[paul swed]

Chris
I have no doubt someone will snap it up even for a re-sale. Some dealer.
The best of luck to you. Nice unit
Paul
WB8TSL

On Wed, Feb 27, 2013 at 6:01 PM, Chris Howard  wrote:

>
> I've decided to list my FTS-4060 on ebay, item# 151004036331
> No reserve, 10 days.
>
> Notices tacked on the local telephone poles just have not
> resulted in much interest.
>
> Chris
>
>
>
>
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>
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[time-nuts] Z3805A/58503A time receiver : 2 questions

[Claude Fender]

Hello,

This is my first message here although I read this list for a few weeks.

 I bought a Z3805A/58503A frequency receiver  and I didn't notice on the 
pictures that the model number was not  written on the front panel. It's not 
important but is there a reason for that, if you know ?
The item : http://cgi.ebay.fr/ws/eBayISAPI.dll?ViewItem&item=251226027893 


I log some parameters of the receiver and today I notice a "gap" in the 
frequency.

Picture : http://uppix.net/e/2/4/cf39ac772e5a69fc616f5cf30f208.png

I have a Rubidium and I measure it's frequency with a 5334B counter locked to 
the GPS, and I can see the "gap" too :
http://uppix.net/f/b/a/d86c2737ad135264e4a2b78e503d5.png
measurements are with Gate Time of 10s, 60s and 100s, 


Do you know why this happens and how to prevent this behaviour ?

Thanks for yours advices 


Claude
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Re: [time-nuts] Z3805A/58503A time receiver : 2 questions

[SAIDJACK]

Hello Claude,
 
that gap is a classic crystal jump. It could be caused by the crystal  
changing frequency by itself, or by being hit with e.g. gamma particles etc.  
Could also have been instigated by vibration or shock to the unit.
 
You should be seeing 6+ sats at all times though, your plot shows you  
sometimes seem to see 2 or 3 sats only? Maybe a better antenna position would  
help the stability of that unit.
 
Nothing to worry about if it doesn't happen regularly. Enjoy,
 
bye,
Said
 
 
In a message dated 2/27/2013 15:18:51 Pacific Standard Time,  
lab...@yahoo.fr writes:

Hello,

This is my first message here although I read this  list for a few weeks.

I bought a Z3805A/58503A frequency  receiver  and I didn't notice on the 
pictures that the model number was  not  written on the front panel. It's not 
important but is there a reason  for that, if you know ?
The item :  http://cgi.ebay.fr/ws/eBayISAPI.dll?ViewItem&item=251226027893  


I log some parameters of the receiver and today I notice a "gap"  in the 
frequency.

Picture :  http://uppix.net/e/2/4/cf39ac772e5a69fc616f5cf30f208.png

I have a  Rubidium and I measure it's frequency with a 5334B counter locked 
to the GPS,  and I can see the "gap" too  :
http://uppix.net/f/b/a/d86c2737ad135264e4a2b78e503d5.png
measurements  are with Gate Time of 10s, 60s and 100s, 


Do you know why this  happens and how to prevent this behaviour ?

Thanks for yours advices  


Claude

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Re: [time-nuts] Lady Heather numbers

[Bob Camp]

Hi

Your makeshift oven is changing >= 0.008C when the ambient temperature changes 
2.5C. The frequency of the OCXO tracks the temperature as reported by the 
TBolt's sensor. It is NOT being controlled by the TBolt's sensor. 

Bob

On Feb 27, 2013, at 5:43 PM, Garren Davis  wrote:

> 
> Opps, Now your confusing me. You say the tbolt does not use the temperature 
> monitor when in locked mode. In your previous message you said "The 
> temperature of your TBolt is moving 2.5 C. The OCXO frequency directly 
> follows this temperature". Do you mean the inner oven is changing .008C 
> because of the 2.5C change in the outer oven?
> I'll back away from all the questions for a while and study this a bit. 
> Probably move some thermistors to different locations.
> 
> It is fun trying different things and seeing what happens.
> 
> Garren
> 
> -Original Message-
> From: time-nuts-boun...@febo.com [mailto:time-nuts-boun...@febo.com] On 
> Behalf Of Bob Camp
> Sent: Wednesday, February 27, 2013 12:12 PM
> To: 'Discussion of precise time and frequency measurement'
> Subject: Re: [time-nuts] Lady Heather numbers
> 
> Hi
> 
> The TBolt does not use the temperature monitor when in locked mode. Your OCXO 
> is changing temperature. Roughly a 0.008 C temperature change would explain 
> the movement you see.
> 
> Bob
> 
> -Original Message-
> From: time-nuts-boun...@febo.com [mailto:time-nuts-boun...@febo.com] On 
> Behalf Of Garren Davis
> Sent: Wednesday, February 27, 2013 1:20 PM
> To: Discussion of precise time and frequency measurement
> Subject: Re: [time-nuts] Lady Heather numbers
> 
> 
> I don't doubt that my oven could be the problem but I would think a lot of 
> people have their tbolts sitting in a room or basement with a lot more 
> temperature swing than 2.5C. I also monitor the inner oven temperature where 
> the oscillator is located and it remains stable at 67C regardless of the 2.5C 
> swing of the outer oven. This makes me wonder if the tbolt temperature is 
> used in the algorithm that steers the osc frequency. I'll have to try some 
> experiments to see if I can figure this out.
> 
> Thanks for the feedback Bob.
> 
> Garren
> 
> 
> -Original Message-
> From: time-nuts-boun...@febo.com [mailto:time-nuts-boun...@febo.com] On 
> Behalf Of Bob Camp
> Sent: Wednesday, February 27, 2013 9:49 AM
> To: 'Discussion of precise time and frequency measurement'
> Subject: Re: [time-nuts] Lady Heather numbers
> 
> Hi
> 
> The temperature of your TBolt is moving 2.5 C. The OCXO frequency directly 
> follows this temperature. The OCXO is likely moving 3 ppb as the temperature 
> changes by 2.5C. That drives the PPS back and forth.
> 
> Put another way - most of what you see is related to the problem with the 
> OCXO and it's lack of a proper oven.
> 
> Bob
> 
> -Original Message-
> From: time-nuts-boun...@febo.com [mailto:time-nuts-boun...@febo.com] On 
> Behalf Of Garren Davis
> Sent: Wednesday, February 27, 2013 10:27 AM
> To: Discussion of precise time and frequency measurement
> Subject: Re: [time-nuts] Lady Heather numbers
> 
> 
> Warren,
> 
> Thanks for the comments. I've included a 34 hour screen dump. Trying to 
> understand why the PPS trace is doing what it is doing. Looks like it might 
> have something to do with the temperature.
> 
> I'm going to try a different GPS antenna and mount it higher this weekend.
> I'll do a 24 hour
> survey and start another run. After that I'll try a different power supply.
> Right now I'm
> using a PC power supply. It's probably a bit noisy.
> 
> Garren
> 
> 
> -Original Message-
> From: time-nuts-boun...@febo.com [mailto:time-nuts-boun...@febo.com] On 
> Behalf Of WarrenS
> Sent: Tuesday, February 26, 2013 10:53 AM
> To: Discussion of precise time and frequency measurement
> Subject: Re: [time-nuts] Lady Heather numbers
> 
>> Can anyone comment on the picture.
>> I don't know if what I have would be considered good as far as accuracy
>> and stability is concerned.
> 
> The screen dump is way too short to give much detail.
> What can be said from what is there:
> From a Ham standpoint it is all working fine and is much better than 1e-9.
> 
> From a time nut standpoint it is very poor.
> It is using the default setting (for the most part) Phase error at -100ns is
> ~50 times high for the 100 sec TC setting used, (likely due to the high drift 
> rate of the Osc) Frequency error is wondering around 1e-10 is about 50 times 
> higher than what is possible.
> Effect on freq and phase noise with sat changes is >>10 times more that what 
> is possible with good setup.
> 
> Concerning your Dac comments, Yes makes sense, but your conclusing is wrong.
> Can't say or sure, because the 24 Hr + screen shot is not shown, but in 
> general The Tbolt temperature reading has no direct effect on the Dac control 
> voltage unless the Tbolt is in hold over.
> The Dac voltage changes because the oscillator's freq is trying to change, 
> not the other way aroun

Re: [time-nuts] Newbie question about thunderbolts

[John Miles]

Sounds like a bad OCXO.  The crystal frequency jumps slightly, and the
disciplining loop then has to compensate by steering the DAC  voltage
through the loop filter.  If that's the problem it may get better if you
leave it running for a few more weeks.

The smoking gun is the attack/decay characteristic of the DAC adjustment.
At least in theory, no issues on the GPS side of the loop should result in a
fast leading edge at the DAC. 

I haven't seen any Thunderbolts with genuinely bad OCXOs yet, although some
of them are definitely better than others.  The Thunderbolt-E, however, is a
very different model than the ones that are normally found on eBay.  Almost
everything you hear about a "Thunderbolt" refers to the older non-E version.


I've heard (but can't exactly cite) that the Thunderbolt E models were a
reduced-cost, higher-volume product.  If that's true, you can assume that
they don't use the same OCXOs, because those OCXOs were much better -- and
would have been more expensive -- than they had to be.  

(The Thunderbolt E should not be confused with the more common Thunderbolts
running 'E'-level firmware.)

-- john, KE5FX

> Hi, Paul. Glad to see you made it here. For the time-nuts; Paul and I
> have spoken about these issues, and I have had similar experience. The
> only thing I would add is the the spikes to seem to occur less
> frequently with a better antenna placement, but when they start to
> cluster, they fire off one every two or three seconds, sometimes
> faster.
> 
> JimT
> 
> On Wed, Feb 27, 2013 at 2:08 PM, Paul Berger  wrote:
> >
> > Hello all:
> >
> > I am an electronic technician with 30+ years experience fixing
> > computers.   In my spare time I like to play with old computers and
> > electronics.  Recently I got bit by the precision timing bug, partially
> > after running across the wonderful leapsecond.com site, which lead me
> > here.   First I got  a FE-5680A, then after reading some of the archives
> > here I bought a Nortel / Trimble 45000   GPSDO and still later a used
> > Thunderbolt-E...

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Re: [time-nuts] Z3805A/58503A time receiver : 2 questions

[Volker Esper]

Hi Claude!

Said says, you should see 6+ sats, I guess he means _at_least_ six. I'm 
almost sure, you've got a 6 channel receiver, so you naturally cant't 
get more than 6 sats at a time.


There are some different models of the Z3805A out there, though they're 
all named the same. I've got two units, one with an 8 channel and one 
with a 16 channel receiver. My 8channel unit never receives more than 6 
sats at a time, never. So I'm shure, it's a 6 channel type...


Maybe I should improve my antenna. But the same antenna provides enough 
voltage to receive 12 to 14 sats at once with the 16 channel unit. On 
the other hand, my 6/8 channel gizmo very rarely shows less than 6 sats, 
so, like Said, I too think, that there is some space for improving your 
antenna. What antenna do you have?


One day, while using the 16 channel unit, I experienced the same hops as 
you did. All time nuts told me that it had to be a crystal jump. I read 
about such phenomenons and all I found was, that the jump in my receiver 
was too big to fit to the idea of a crystal jump. Unfortunately my 
receiver gained fun in jumping. Now I'm absolutely not sure what it is. 
Maybe it's a faulty oscillator. Which one do you have built in? A 5 or a 
10 MHz type? I've got a 10 MHz HP and a 5 MHz Symmetricom oscillator.


Cheers

Volker



Am 28.02.2013 00:17, schrieb Claude Fender:

Hello,

This is my first message here although I read this list for a few weeks.

  I bought a Z3805A/58503A frequency receiver  and I didn't notice on the 
pictures that the model number was not  written on the front panel. It's not 
important but is there a reason for that, if you know ?
The item : http://cgi.ebay.fr/ws/eBayISAPI.dll?ViewItem&item=251226027893


I log some parameters of the receiver and today I notice a "gap" in the 
frequency.

Picture : http://uppix.net/e/2/4/cf39ac772e5a69fc616f5cf30f208.png

I have a Rubidium and I measure it's frequency with a 5334B counter locked to the GPS, 
and I can see the "gap" too :
http://uppix.net/f/b/a/d86c2737ad135264e4a2b78e503d5.png
measurements are with Gate Time of 10s, 60s and 100s,


Do you know why this happens and how to prevent this behaviour ?

Thanks for yours advices


Claude
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Re: [time-nuts] Newbie question about thunderbolts

[Paul Berger]

I did peek inside the E not long after I got it and I do remember that 
the OXCO looks very different, it is much smaller than the one on my 
Nortel unit.  If it is the OXCO I can always source a potentially better 
OXCO and then I can have more fun playing with it.  Being a technician I 
really enjoy fixing things and seeing them work again.  One other big 
difference in the E model is it takes a single 24VDC power input and has 
a little switcher module in it to generate the voltage the GPSDO 
actually uses, this is similar to the setup on the Nortel unit, however 
it did not look to be built nearly as good.  I will give it a little 
more time and if it does not improve I will pull it out of its box and 
start to poke around inside.


Paul.

On 2/27/13 8:23 PM, John Miles wrote:

Sounds like a bad OCXO.  The crystal frequency jumps slightly, and the
disciplining loop then has to compensate by steering the DAC  voltage
through the loop filter.  If that's the problem it may get better if you
leave it running for a few more weeks.

The smoking gun is the attack/decay characteristic of the DAC adjustment.
At least in theory, no issues on the GPS side of the loop should result in a
fast leading edge at the DAC.

I haven't seen any Thunderbolts with genuinely bad OCXOs yet, although some
of them are definitely better than others.  The Thunderbolt-E, however, is a
very different model than the ones that are normally found on eBay.  Almost
everything you hear about a "Thunderbolt" refers to the older non-E version.


I've heard (but can't exactly cite) that the Thunderbolt E models were a
reduced-cost, higher-volume product.  If that's true, you can assume that
they don't use the same OCXOs, because those OCXOs were much better -- and
would have been more expensive -- than they had to be.

(The Thunderbolt E should not be confused with the more common Thunderbolts
running 'E'-level firmware.)

-- john, KE5FX


Hi, Paul. Glad to see you made it here. For the time-nuts; Paul and I
have spoken about these issues, and I have had similar experience. The
only thing I would add is the the spikes to seem to occur less
frequently with a better antenna placement, but when they start to
cluster, they fire off one every two or three seconds, sometimes
faster.

JimT

On Wed, Feb 27, 2013 at 2:08 PM, Paul Berger  wrote:

Hello all:

I am an electronic technician with 30+ years experience fixing
computers.   In my spare time I like to play with old computers and
electronics.  Recently I got bit by the precision timing bug, partially
after running across the wonderful leapsecond.com site, which lead me
here.   First I got  a FE-5680A, then after reading some of the archives
here I bought a Nortel / Trimble 45000   GPSDO and still later a used
Thunderbolt-E...

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Re: [time-nuts] Z3805A/58503A time receiver : 2 questions

[Volker Esper]

I just calculated the frequency offset. I count 5 crosses, while jumping 
down to 200 ns, I guess, 1 cross equals 10 min? So let's say the jump 
lasts 60 min (= T jump). When we want to calculate the frequency offset 
out of a phase jump, we have to differentiate the phase and we should 
achieve


delta f = delta phase / delta T
delta f = (delta t / T period) / T jump
delta f = (200ns / 100ns) / 60 min
delta f = 0,55 mHz (milli, not Mega!)

What precision / stability do you demand?

Volker


Am 28.02.2013 00:47, schrieb saidj...@aol.com:

Hello Claude,

that gap is a classic crystal jump. It could be caused by the crystal
changing frequency by itself, or by being hit with e.g. gamma particles etc.
Could also have been instigated by vibration or shock to the unit.

You should be seeing 6+ sats at all times though, your plot shows you
sometimes seem to see 2 or 3 sats only? Maybe a better antenna position would
help the stability of that unit.

Nothing to worry about if it doesn't happen regularly. Enjoy,

bye,
Said


In a message dated 2/27/2013 15:18:51 Pacific Standard Time,
lab...@yahoo.fr writes:

Hello,

This is my first message here although I read this  list for a few weeks.

I bought a Z3805A/58503A frequency  receiver  and I didn't notice on the
pictures that the model number was  not  written on the front panel. It's not
important but is there a reason  for that, if you know ?
The item :  http://cgi.ebay.fr/ws/eBayISAPI.dll?ViewItem&item=251226027893


I log some parameters of the receiver and today I notice a "gap"  in the
frequency.

Picture :  http://uppix.net/e/2/4/cf39ac772e5a69fc616f5cf30f208.png

I have a  Rubidium and I measure it's frequency with a 5334B counter locked
to the GPS,  and I can see the "gap" too  :
http://uppix.net/f/b/a/d86c2737ad135264e4a2b78e503d5.png
measurements  are with Gate Time of 10s, 60s and 100s,


Do you know why this  happens and how to prevent this behaviour ?

Thanks for yours advices


Claude

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Re: [time-nuts] Newbie question about thunderbolts

[EWKehren]

I did get one bad one leak or pin hole aging so much that it would have run 
 out of tuning range in a month
Bert Kehren
 
 
In a message dated 2/27/2013 7:24:25 P.M. Eastern Standard Time,  
jmi...@pop.net writes:

Sounds  like a bad OCXO.  The crystal frequency jumps slightly, and  the
disciplining loop then has to compensate by steering the DAC   voltage
through the loop filter.  If that's the problem it may get  better if you
leave it running for a few more weeks.

The smoking gun  is the attack/decay characteristic of the DAC adjustment.
At least in  theory, no issues on the GPS side of the loop should result in 
a
fast  leading edge at the DAC. 

I haven't seen any Thunderbolts with  genuinely bad OCXOs yet, although some
of them are definitely better than  others.  The Thunderbolt-E, however, is 
a
very different model than  the ones that are normally found on eBay.  Almost
everything you hear  about a "Thunderbolt" refers to the older non-E 
version.


I've heard  (but can't exactly cite) that the Thunderbolt E models were a
reduced-cost,  higher-volume product.  If that's true, you can assume that
they don't  use the same OCXOs, because those OCXOs were much better -- and
would have  been more expensive -- than they had to be.  

(The Thunderbolt E  should not be confused with the more common Thunderbolts
running 'E'-level  firmware.)

-- john, KE5FX

> Hi, Paul. Glad to see you made it  here. For the time-nuts; Paul and I
> have spoken about these issues,  and I have had similar experience. The
> only thing I would add is the  the spikes to seem to occur less
> frequently with a better antenna  placement, but when they start to
> cluster, they fire off one every two  or three seconds, sometimes
> faster.
> 
> JimT
>  
> On Wed, Feb 27, 2013 at 2:08 PM, Paul Berger   wrote:
> >
> > Hello all:
>  >
> > I am an electronic technician with 30+ years experience  fixing
> > computers.   In my spare time I like to play  with old computers and
> > electronics.  Recently I got bit by  the precision timing bug, partially
> > after running across the  wonderful leapsecond.com site, which lead me
> > here.First I got  a FE-5680A, then after reading some of the 
archives
>  > here I bought a Nortel / Trimble 45000   GPSDO and still later  a used
> >  Thunderbolt-E...

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Re: [time-nuts] Z3805A/58503A time receiver : 2 questions

[Volker Esper]

If your unit is exactly like that on ebay 251226027893, it has a 10 MHz 
HP oscillator in a double oven, and it's absolutely sure that it's got a 
6 channel receiver.


I should have read before, sorry.

I'm still not sure about your antenna, is it a Garmin? Well, it's most 
likely an active type, so what gain does it have? If you installed it on 
a roof top, it should see sufficient field strength.
Then do that simple test: disconnect your antenna from the receiver unit 
and measure with a multimeter the voltage at the center pin of your N 
connecter antenna plug. It has to show 5 Volts, otherwise your antenna 
can't be working well.


Volker


Am 28.02.2013 01:26, schrieb Volker Esper:


Hi Claude!

Said says, you should see 6+ sats, I guess he means _at_least_ six. 
I'm almost sure, you've got a 6 channel receiver, so you naturally 
cant't get more than 6 sats at a time.


There are some different models of the Z3805A out there, though 
they're all named the same. I've got two units, one with an 8 channel 
and one with a 16 channel receiver. My 8channel unit never receives 
more than 6 sats at a time, never. So I'm shure, it's a 6 channel type...


Maybe I should improve my antenna. But the same antenna provides 
enough voltage to receive 12 to 14 sats at once with the 16 channel 
unit. On the other hand, my 6/8 channel gizmo very rarely shows less 
than 6 sats, so, like Said, I too think, that there is some space for 
improving your antenna. What antenna do you have?


One day, while using the 16 channel unit, I experienced the same hops 
as you did. All time nuts told me that it had to be a crystal jump. I 
read about such phenomenons and all I found was, that the jump in my 
receiver was too big to fit to the idea of a crystal jump. 
Unfortunately my receiver gained fun in jumping. Now I'm absolutely 
not sure what it is. Maybe it's a faulty oscillator. Which one do you 
have built in? A 5 or a 10 MHz type? I've got a 10 MHz HP and a 5 MHz 
Symmetricom oscillator.


Cheers

Volker



Am 28.02.2013 00:17, schrieb Claude Fender:

Hello,

This is my first message here although I read this list for a few weeks.

  I bought a Z3805A/58503A frequency receiver  and I didn't notice on 
the pictures that the model number was not  written on the front 
panel. It's not important but is there a reason for that, if you know ?
The item : 
http://cgi.ebay.fr/ws/eBayISAPI.dll?ViewItem&item=251226027893



I log some parameters of the receiver and today I notice a "gap" in 
the frequency.


Picture : http://uppix.net/e/2/4/cf39ac772e5a69fc616f5cf30f208.png

I have a Rubidium and I measure it's frequency with a 5334B counter 
locked to the GPS, and I can see the "gap" too :

http://uppix.net/f/b/a/d86c2737ad135264e4a2b78e503d5.png
measurements are with Gate Time of 10s, 60s and 100s,


Do you know why this happens and how to prevent this behaviour ?

Thanks for yours advices


Claude
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Re: [time-nuts] Newbie question about thunderbolts

[Bob Camp]

Hi

An "E series" Thunderbolt is about 4X the size of the later Thunderbolt, 
sometimes called an E. Yes it's very confusing. 

If the OCXO is about 1" on a side and the unit is maybe 1.5" wide, then you 
have the later version of the Thunderbolt. Probably the best way to confirm 
this and eliminate the confusion would be a picture.

Bob

On Feb 27, 2013, at 7:35 PM, Paul Berger  wrote:

> I did peek inside the E not long after I got it and I do remember that the 
> OXCO looks very different, it is much smaller than the one on my Nortel unit. 
>  If it is the OXCO I can always source a potentially better OXCO and then I 
> can have more fun playing with it.  Being a technician I really enjoy fixing 
> things and seeing them work again.  One other big difference in the E model 
> is it takes a single 24VDC power input and has a little switcher module in it 
> to generate the voltage the GPSDO actually uses, this is similar to the setup 
> on the Nortel unit, however it did not look to be built nearly as good.  I 
> will give it a little more time and if it does not improve I will pull it out 
> of its box and start to poke around inside.
> 
> Paul.
> 
> On 2/27/13 8:23 PM, John Miles wrote:
>> Sounds like a bad OCXO.  The crystal frequency jumps slightly, and the
>> disciplining loop then has to compensate by steering the DAC  voltage
>> through the loop filter.  If that's the problem it may get better if you
>> leave it running for a few more weeks.
>> 
>> The smoking gun is the attack/decay characteristic of the DAC adjustment.
>> At least in theory, no issues on the GPS side of the loop should result in a
>> fast leading edge at the DAC.
>> 
>> I haven't seen any Thunderbolts with genuinely bad OCXOs yet, although some
>> of them are definitely better than others.  The Thunderbolt-E, however, is a
>> very different model than the ones that are normally found on eBay.  Almost
>> everything you hear about a "Thunderbolt" refers to the older non-E version.
>> 
>> 
>> I've heard (but can't exactly cite) that the Thunderbolt E models were a
>> reduced-cost, higher-volume product.  If that's true, you can assume that
>> they don't use the same OCXOs, because those OCXOs were much better -- and
>> would have been more expensive -- than they had to be.
>> 
>> (The Thunderbolt E should not be confused with the more common Thunderbolts
>> running 'E'-level firmware.)
>> 
>> -- john, KE5FX
>> 
>>> Hi, Paul. Glad to see you made it here. For the time-nuts; Paul and I
>>> have spoken about these issues, and I have had similar experience. The
>>> only thing I would add is the the spikes to seem to occur less
>>> frequently with a better antenna placement, but when they start to
>>> cluster, they fire off one every two or three seconds, sometimes
>>> faster.
>>> 
>>> JimT
>>> 
>>> On Wed, Feb 27, 2013 at 2:08 PM, Paul Berger  wrote:
 Hello all:
 
 I am an electronic technician with 30+ years experience fixing
 computers.   In my spare time I like to play with old computers and
 electronics.  Recently I got bit by the precision timing bug, partially
 after running across the wonderful leapsecond.com site, which lead me
 here.   First I got  a FE-5680A, then after reading some of the archives
 here I bought a Nortel / Trimble 45000   GPSDO and still later a used
 Thunderbolt-E...
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Re: [time-nuts] Newbie question about thunderbolts

[Paul Berger]

Bob:

I am quite sure this is a Thunderbolt E as opposed to the E series of 
the earlier Thunderbolt, the blue label on top of the aluminum box says 
"Thunderbolt E" the blue Trimble box that it came in says "Thunderbolt E 
Starter Kit" and yes as I said below the OCXO is smaller than the one on 
my Nortel unit, it is roughly the same footprint as the Trimble 34310 
OXCO on the Nortel unit but less than half the height.  It looks just 
like the picture here on Trimble's website. 
http://www.trimble.com/timing/thunderbolt-e.aspx


Paul.

On 2/27/13 9:43 PM, Bob Camp wrote:

Hi

An "E series" Thunderbolt is about 4X the size of the later Thunderbolt, 
sometimes called an E. Yes it's very confusing.

If the OCXO is about 1" on a side and the unit is maybe 1.5" wide, then you 
have the later version of the Thunderbolt. Probably the best way to confirm this and 
eliminate the confusion would be a picture.

Bob

On Feb 27, 2013, at 7:35 PM, Paul Berger  wrote:


I did peek inside the E not long after I got it and I do remember that the OXCO 
looks very different, it is much smaller than the one on my Nortel unit.  If it 
is the OXCO I can always source a potentially better OXCO and then I can have 
more fun playing with it.  Being a technician I really enjoy fixing things and 
seeing them work again.  One other big difference in the E model is it takes a 
single 24VDC power input and has a little switcher module in it to generate the 
voltage the GPSDO actually uses, this is similar to the setup on the Nortel 
unit, however it did not look to be built nearly as good.  I will give it a 
little more time and if it does not improve I will pull it out of its box and 
start to poke around inside.

Paul.

On 2/27/13 8:23 PM, John Miles wrote:

Sounds like a bad OCXO.  The crystal frequency jumps slightly, and the
disciplining loop then has to compensate by steering the DAC  voltage
through the loop filter.  If that's the problem it may get better if you
leave it running for a few more weeks.

The smoking gun is the attack/decay characteristic of the DAC adjustment.
At least in theory, no issues on the GPS side of the loop should result in a
fast leading edge at the DAC.

I haven't seen any Thunderbolts with genuinely bad OCXOs yet, although some
of them are definitely better than others.  The Thunderbolt-E, however, is a
very different model than the ones that are normally found on eBay.  Almost
everything you hear about a "Thunderbolt" refers to the older non-E version.


I've heard (but can't exactly cite) that the Thunderbolt E models were a
reduced-cost, higher-volume product.  If that's true, you can assume that
they don't use the same OCXOs, because those OCXOs were much better -- and
would have been more expensive -- than they had to be.

(The Thunderbolt E should not be confused with the more common Thunderbolts
running 'E'-level firmware.)

-- john, KE5FX


Hi, Paul. Glad to see you made it here. For the time-nuts; Paul and I
have spoken about these issues, and I have had similar experience. The
only thing I would add is the the spikes to seem to occur less
frequently with a better antenna placement, but when they start to
cluster, they fire off one every two or three seconds, sometimes
faster.

JimT

On Wed, Feb 27, 2013 at 2:08 PM, Paul Berger  wrote:

Hello all:

I am an electronic technician with 30+ years experience fixing
computers.   In my spare time I like to play with old computers and
electronics.  Recently I got bit by the precision timing bug, partially
after running across the wonderful leapsecond.com site, which lead me
here.   First I got  a FE-5680A, then after reading some of the archives
here I bought a Nortel / Trimble 45000   GPSDO and still later a used
Thunderbolt-E...

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Re: [time-nuts] Advise on HP-5335a features

[Gary Chatters]

On 02/27/2013 01:09 PM, Paul Berger wrote:

I am considering getting a counter with better resolution than my 5316A,
and have been looking at 5335A, they seem to be quite capable and fit my
budget, but I have some questions about options.



Have you considered the 5334A?  It has the same spec for resolution, 9 
digits/sec, but does not come with the noisy fan that the 5335A has.  It 
is also smaller: 2U vs 3U height.


The 5335A does have some advantages over the 5334A: Higher upper 
frequency limit (200 MHz vs. 100MHz) and more statistics capabilities 
(which I have not yet learned how to use).


They both have scale and offset capability.


1. How useful is the option 020 DC voltmeter?  Does it offer good
resolution?


I have the option, but never even think of using it.  The common HP3478A 
DMM is faster and has better resolution.  If I did not have a DMM, then 
it could be useful.



2. Is the option 040 a desirable feature?  Will it improve the
performance of the counter?  or would I be better off getting one with
the OXCO feature?



I do not have GPIB capability, so can not say how useful 040 is.  The 
channel C option (030) which extends the range to 1.3 GHz is useful if 
you have any radios for bands above 2m.



Gary


I also looked at a 5370A that was in my price range however the seller
would only ship by UPS and the cost of shipping was as much as the 5370A
even before UPS skins me for bringing it across the border, all the
other 5370s where out of reach.


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Re: [time-nuts] FE-5680A DDS Board/PIC Code

[Magnus Danielson]

On 02/18/2013 10:32 PM, Herbert Poetzl wrote:


I'm new to the time-nuts community, so I simply start
with a short info on how I got into this situation :)
(skip forward to  if not interested)

Not long ago, I decided to build a reasonably good
frequency counter for my personal use and maybe if
the result is simple and elegant, I'll publish the
details so that everybody can build one ...

It was clear to me, that it had to be able to count
up to at least 1GHz and thus show at least nine,
better ten significant digits, so a precise time base
is required.

After some online searches and investigations, my
best options seemed to get a very stable oscillator
and a high quality time reference to sync with, which
in turn brought me to the idea to use a cheap rubidium
normal and somehow tune/measure/sync it via GPS or
DCF-77/MSF-60.

Reading a lot of documentation and blogs from all over
the world (sometimes in translation :) shed some light
on the rubidium normal requirements, which I defined as:

  - has to have a 10MHz output not just the 1PPS
  - has to be programmable (i.e. can be tuned)
  - must be cheap

I quickly found two different RB standard models,
readily available on ebay for a reasonable price,
namely the Efratom FRS-C and the FEI FE-5680A.
I finally decided to go with the FE-5680A, mainly
because I liked the package. A seller was quickly
found offering something titled:

  'FE-5680A Rubidium Atomic Frequency Standard
   Oscillator Transceivers 10Mhz Out'
  'Programmable from 1Hz to 20MHz'

Little did I know what that actually meant ...

When the units (I ordered two of them) arrived, I
couldn't wait to test if they actually work and get
a lock, so I quickly wired them up (according to the
pinout) and provided them with the advised 15V at
up to 2A each. To my astonishment, they heated up
rather quickly and got a lock in a little under two
minutes, so I happily got my scope out to check the
10MHz signal, just to find that there is no such
signal available on the 9pin D-sub connector.

Measuring pins against ground (pin 2) and 15Vx (pin 1)
I figured that neither pin 7 (10MHz) nor pin 8/9
(the rs232 interface for programming) was connected.
and to my great disappointment, pin 6 (1PPS) didn't
output much either (I later discovered that this was
due to a defective unit, which is now being replaced)

After contacting the seller, I opened up the units
to investigate my options (and of course, because
I wanted to take a look inside :), which in turn led
to a number of high resolution scans and photos of
all the bits and pieces.

A (this time) more thorough search on the internet
resulted in a deeper understanding of the various
options the FE-5680A can have (or usually doesn't
have) and the inner workings of the different
FE-5680A models (of course, all labeled FE-5680A :)

The DDS board, which actually can be programmed to
output certain frequencies derived from the 'locked'
1:136 frequency of the rubidium 6.8GHz transition,
caught my attention, as it has both, the '10Mhz'
output and the programming interface, so I decided
to analyze it further ...



The central part on this specific DDS board [1] is
the AD9830A a Direct Digital Synthesizer (DDS) which
basically produces a sine wave at a well defined
multiple and phase of a given reference frequency.

Besides some other components, this board also
includes an RS-232C line driver (Sipex SP233A) a
PIC16F84 microcontroller and two 74HC595 8bit shift
registers, with buffered outputs.

I read somewhere, that the blue buttons on that DDS
board can be used to adjust the output frequency,
this should be avoided, mainly because every button
press is an update and will cause a write to the
EEPROM data wearing it out.

Now as I've played with PIC microcontrollers for
a long time, I wanted to know what this specific
controller is doing and how I could use that for my
purposes ...

The chip was quickly removed and the program as well
as configuration memory retrieved (luckily FEI didn't
utilize the code/data protection) and together with
high resolution scans and photos, a documented and
verified assembler listing [2] reverse engineered.

Here are the (IMHO) quite interesting findings:

  - both FREQx registers can be adjusted
  - the PHASE0 register can be adjusted
  - none of the changes is permanent,
unless you explicitely save the settings
  - there are only a few commands, without
any plausibility checks and/or protection
  - and yes, the buttons increment/decrement
the FREQx settings and trigger a write to
the EEPROM after every update.
  - the serial interface is done in software
  - the DDS control words are shifted into
the 74HC595, buffered and written


; S  STATUS
;   R=50255057.012932Hz F=2ABB5040
;   OK
;
; F= FREQxREG (set divider)
;   OK
;
; G= PHASE (set phase register)
;   OK
;
; R=YY   RUBIDIUM (set calibrated fre

Re: [time-nuts] Possibly off topic - Jitter on Ethernet over power adapters

[Magnus Danielson]

On 02/12/2013 08:19 PM, Mike S wrote:

On 2/10/2013 6:04 PM, Magnus Danielson wrote:

You should read "TCP/IP" as "Internet Protocols" (notice plural form
here). It points to the stack of protocols,


Actually, no. IP is Internet Protocol, singular, and is the L3 (mostly -
IP predates the ISO/OSI model layers, so IP suite protocols don't map
exactly) protocol upon which both TCP and UDP are built. It's defined by
RFC 791.

TCP/IP, simply because those are the most commonly used protocols in the
suite.


In the context it was written, it used the well spread misnomer of the 
suite to be referred to TCP/IP. The protocol suite was many times 
referred to as TCP/IP even if UDP was used for the particular transport 
over IP. It is a confusing thing and people have become better at using 
the correct terms, so in the context that "NTP used TCP/IP" is means 
that NTP uses the Internet Protocol suite, not TCP over IP.


As I recall NTPv3 in RFC 1305, it only specifies UDP over IP.

The ISO/OSI model stuff is a bad fit for the IP-stack, but it got stuck 
and fits the reality really bad. It's usage is discouraged.


Cheers,
Magnus
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Re: [time-nuts] Possibly off topic - Jitter on Ethernet over power adapters

[Chris Albertson]

On Wed, Feb 27, 2013 at 7:02 PM, Magnus Danielson
 wrote:
> On 02/12/2013 08:19 PM, Mike S wrote:
>>
>> On 2/10/2013 6:04 PM, Magnus Danielson wrote:
>>>
>>> You should read "TCP/IP" as "Internet Protocols" (notice plural form

No.  The best way to pronouncethe slanted bar is "over".

So you say "TCP over IP"
Notice that we also many times have UDP/IP

If you what to know what al the letters are it is "Transaction Control
Protocol over Internetwork Protocol"

TCP is a way to ensure a packet gets to an end point and in the same
order they were sent.  "IP" is a way to move packets.  TCP makes use
of I to send packets.

"UDP" is User Datagram Protocol and it also use IP.

In turn IP can run over any number of physical networks like Ethernet,
WiFi X25, or ISDN.

Chris Albertson
Redondo Beach, California
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Re: [time-nuts] Possibly off topic - Jitter on Ethernet over poweradapters

[DaveH]

IP can be run on a lot of different platforms.

Check out Request for Comments: 1149

http://www.ietf.org/rfc/rfc1149.txt

Dave
 

> -Original Message-
> From: time-nuts-boun...@febo.com 
> [mailto:time-nuts-boun...@febo.com] On Behalf Of Chris Albertson
> Sent: Wednesday, February 27, 2013 21:31
> To: Discussion of precise time and frequency measurement
> Subject: Re: [time-nuts] Possibly off topic - Jitter on 
> Ethernet over poweradapters
> 
> On Wed, Feb 27, 2013 at 7:02 PM, Magnus Danielson
>  wrote:
> > On 02/12/2013 08:19 PM, Mike S wrote:
> >>
> >> On 2/10/2013 6:04 PM, Magnus Danielson wrote:
> >>>
> >>> You should read "TCP/IP" as "Internet Protocols" (notice 
> plural form
> 
> No.  The best way to pronouncethe slanted bar is "over".
> 
> So you say "TCP over IP"
> Notice that we also many times have UDP/IP
> 
> If you what to know what al the letters are it is "Transaction Control
> Protocol over Internetwork Protocol"
> 
> TCP is a way to ensure a packet gets to an end point and in the same
> order they were sent.  "IP" is a way to move packets.  TCP makes use
> of I to send packets.
> 
> "UDP" is User Datagram Protocol and it also use IP.
> 
> In turn IP can run over any number of physical networks like Ethernet,
> WiFi X25, or ISDN.
> 
> Chris Albertson
> Redondo Beach, California
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Re: [time-nuts] Possibly off topic - Jitter on Ethernet over poweradapters

[Chris Albertson]

On Wed, Feb 27, 2013 at 9:54 PM, DaveH  wrote:
> IP can be run on a lot of different platforms.
>
> Check out Request for Comments: 1149

Even better, check out the guys who actually implemented RFC1149.
This page has links.
http://www.blug.linux.no/rfc1149/


Chris Albertson
Redondo Beach, California
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[time-nuts] GPSDO with a RaspberryPi

[Azelio Boriani]

First try at a simple GPSDO for the RaspberryPi. See here:
http://www.c-c-i.com/exchange/for the file PiAutoTIC1.zip
Thanks to Bob Smither for his file exchange site.
This project is completely open-source, VHDL and C sources are available.
Can be implemented also with any uP but the C source must be heavily
modified.
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