Re: [time-nuts] A couple of Tbolt questions

[John Miles]

> Didn't that older unit use a different oscillator anyway?

Yes.  Its broadband PN wasn't that bad, but it wasn't very clean/stable at
short timescales.

Further complicating matters is that my old Thunderbolt probably had 10,000
or more hours on it before I ever even gained the ability to measure its
phase noise.  Maybe it was better when it was brand new, and maybe the TAPR
units will be noisier after 10,000 hours.  Age doesn't have much effect on
PN in my experience, but that experience is still rather limited.

> I seem to remember from your web page notes that it used a Piezo
> oscillator
>  but any I've seen since, whether firmware version 2.2 or 3.0 and
> including TAPR units and units from two Chinese sources a couple
> of years  apart,
> have used the Trimble 37265 oscillator.
>
> Perhaps the Trimble oscillator is generally cleaner than the
> Piezo one by
> default?

That's what I've been assuming all along, but the idea that some of them
were hand-selected for PN is new to me.

-- john, KE5FX




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Re: [time-nuts] A couple of Tbolt questions

[John Miles]

>
> >I opened the mute Tbolt up to check the solder connections on
> the DB9 and I
> >see it has version 2.2 firmware. How big a deal is it that it
> doesn't have
> >3.0? Also, it has the Trimble 37265 OCXO. I understand that
> there were good
> >and not so good OCXOs used in these. Is this one of the good ones?
> >___
>
> The Oscillator is the same as I have in the TAPR version.
> Underneath I found
> a label 'Phase Noise'. I guess this will be found on all OCXO of
> this version,
> perhaps indicating a lower phase noise then normal. So that OCXO
> should be fine!

Now that's interesting.  Maybe that's why these units are so much cleaner
than the old one I had.  Has anyone else removed the OCXO from a
TAPR-purchased unit and noticed one of those labels?

-- john, KE5FX



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Re: [time-nuts] Trimble Thunderboltsetup optimizationand addinga10811 OCXO

[John Miles]

> How do you realize theset influences?
> What are your results for the TB with the 10811 on EFC, PPS and
> Osc.?
> What setting are you applying?

Subjectively, just watching 30-hour plots on Heather, I see about the same
performance on PPS and Osc as I do on the much-newer TAPR unit.  The EFC
showed a steady increase on a 1-volt scale (~100x worse than the TAPR unit),
probably because of the storage time.  It hadn't flattened out entirely
after 30 hours.

I had to reclaim the bench space this evening so I can't look at it any
closer right now.

I did see occasional jumps with this 10811, nothing extremely bad, but a bit
worse than the worst OSC spikes I tend to see on the TAPR unit.

My conclusion from earlier still seems valid, in that this particular 10811
upgrade brings the older Thunderbolt up to approximately the same level of
performance being seen with the TAPR units.

-- john, KE5FX



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Re: [time-nuts] Apollo, space and time

[John Miles]

Two other recent links of interest, as long as we're posting 'em:

http://forms.butterfields.com/pdf/17402_Space_lowres.pdf (7 MB): Catalog of
personal artifacts from the Mercury to Shuttle eras being sold at auction
tomorrow, at least partly for charity.  Not particularly timing-related but
still well worth browsing.

http://books.google.com/books?id=DpW_hGoo-NUC&lpg=PP1&dq=quantum%20beat&pg=P
P1 : Great book, technically literate but still accessible to
non-physicists.  Unusual for Google Books to include this much material from
the printed edition; they sold at least one copy (mine) by doing that.  Will
make you want to homebrew an H-maser.

-- john, KE5FX


> -Original Message-
> From: time-nuts-boun...@febo.com [mailto:time-nuts-boun...@febo.com]on
> Behalf Of Tom Van Baak
> Sent: Wednesday, July 15, 2009 8:43 PM
> To: Discussion of precise time and frequency measurement
> Subject: [time-nuts] Apollo, space and time
>
>
> This might be of interest to a number of time-nuts. Its a live
> video/audio feed, exactly 40 years delayed...
>
> http://wechoosethemoon.org/
>
> "website will be recreating the history Apollo 11 lunar mission.
>  You can view photographs and videos from the archives,
>  follow the entire event minute by minute on three separate
>  twitter feeds, and browse thousands of pages of declassified
>  mission documents."
>
> /tvb
>


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Re: [time-nuts] Trimble Thunderbolt setup optimizationand addinga10811 OCXO

[John Miles]

>
> I put in as K0 what I measured several times with the 10811
> as 'gain' with -0.74 Hz/V. Is that not the right way?

Yes, that's fine.  Because the varactor is nonlinear and a small part of the
overall tank circuit C, the tuning gain depends on the adjustment-screw
setting to some extent.  Specifying it within a factor of 2x is reasonably
OK, but it's always better to measure the actual gain by adjusting the
tuning-DAC parameter manually with the output centered at 10.000... MHz.

> I tried to
> use several times also higher values. The result was not impressiv,
> did not give clear signs either.
>
> A factory reset I did not perform yet, but I am trying at the moment
> the proposed 0.2 or even a bit lower values. Tomorrow I will
> check the result, but up to now I do not have a good feeling.

I just pulled my 10811-equipped TBolt out of storage after several months,
and it powered up in a rather confused state.  Before I did a factory reset
on mine, the reported PPS/10 MHz deviations were entirely fictional.  It was
reporting reasonable values, but in reality, it wasn't steering the
oscillator closer than a few parts in 1E-8.  The factory reset cycle fixed
the odd behavior (note that you have to re-enter the tuning-sensitivity
parameter after doing that).

-- john, KE5FX


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Re: [time-nuts] Trimble Thunderbolt setup optimization and addinga10811 OCXO

[John Miles]

What are you using for the Kvco constant with your 10811-based Thunderbolt?
If you don't back it down to -0.2 V/Hz, the loop's damping factor will be
very wrong, which might confuse the firmware.  Check the Kvco, and also do a
factory reset after changing the OCXO to make sure it forgets anything it
might be remembering about the OEM part.  (You might try that, too, Arnold.)

-- john, KE5FX

> -Original Message-
> From: time-nuts-boun...@febo.com [mailto:time-nuts-boun...@febo.com]on
> Behalf Of Don @ True-Cal
> Sent: Monday, July 13, 2009 1:15 PM
> To: Discussion of precise time and frequency measurement
> Subject: Re: [time-nuts] Trimble Thunderbolt setup optimization and
> addinga10811 OCXO
>
>
> Arnold,
>
> I have the same question as well as observations as yours. I have
> been working with both the TBolt and Fury connected to two
> different 10811s. With either the TBolt or Fury, I can't get the
> TC large enough to only provide a nudge to the EFC every few
> minutes. Both receivers get real unstable and cause large Freq
> and PPS swings with large TC numbers. It seems the EFC is
> providing many corrections per minute even with the TBOLT set to
> 300 secs. Anything larger than 300-500 sec. on the TBolt and
> EFCD=150 (don't know what the equates to in secs.) on the Fury
> will cause instability. I have better luck disabling desciplining 
> on the TBolt or disconnecting the antenna on the Fury (no command
> to disable that I have found) when I need to do a Tau 0.1-10 sec.
> low jitter measurement.
>  Regards...
> Don
>
>
>
>


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Re: [time-nuts] EZGPIB & delay triggers

[John Miles]

Hi, Bill --

> > >
> > >> I am trying to use EZGPIB with a HP 5370A and I want to trigger a
> > >> reading on a 10 to 30 second interval.
> > >> I want the use EZGPIB to do long term comparisons of various
> > >> oscillators, I am not interested (at this time)
> > >> on jitter less than tau < 1 seconds or so
> > >>
> > >

I hate to "Osborne" myself since it's still in a pretty incomplete state of
development, but I'm working on a new GPIB app that does one-stop shopping
for time-interval measurements.  It will run on the 5370A/B first.  If you
were to use this app to make the measurements you mentioned, you'd most
likely feed the 1-pps output of your reference source to the Start channel
on the 5370, and feed 10 MHz from the unit under test to the Stop channel.
The program will then receive one result per second from the counter and
draw you an ADEV graph, at which point you can load and display
previously-saved files for direct comparison.  More later on that, just
giving you a heads-up so you don't do any R&D work that you don't actually
have to.

One way you can accomplish the same thing now is to run the 5370b.exe
console app from my package, pipe the output to a file, and read it with
Ulrich's PLOTTER utility (which is a separate app from EZGPIB).  That will
save you from having to do any scripting work.

-- john, KE5FX


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Re: [time-nuts] Maximizing Cs Tube Life

[John Miles]

I recently ran across a paper from the 1980 Frequency Control Symposium, in
which HP and the USNO released their surveys on 5061/5062 failure modes.
There was a special emphasis on beam-tube life, showing strong positive
trends as HP got better at manufacturing the tubes in the 1970s:

Longevity Performance of Cesium-Beam Frequency Standards
http://www.ke5fx.com/cs_life.pdf (5 MB, 12 pages)

The paper obviously doesn't apply directly to the 5071A tubes, which came
out much later, but you can still clearly see the loss of service life
associated with high-performance beam tubes in general.  Seems that 5061A
standard-perf tubes were way out in front of everyone else, back in the day.

-- john, KE5FX

> -Original Message-
> From: time-nuts-boun...@febo.com [mailto:time-nuts-boun...@febo.com]on
> Behalf Of Mark Sims
> Sent: Friday, July 10, 2009 8:09 PM
> To: time-nuts@febo.com
> Subject: [time-nuts] Maximizing Cs Tube Life
>
>
>
> "The candle that burns twice as bright,  burns half as long..."
>
> Are both your units the high-performance version?  These units
> get their performance boost by doubling the beam current...  at
> the expense of half the life.  As a side "benefit" of the
> increased beam current,  you can get increased outgasing of
> contaminants in the tube/cesium supply.
>
>


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Re: [time-nuts] Maximizing Cs Tube Life

[John Miles]

>
> "The candle that burns twice as bright,  burns half as long..."
>
> Are both your units the high-performance version?  These units
> get their performance boost by doubling the beam current...  at
> the expense of half the life.  As a side "benefit" of the
> increased beam current,  you can get increased outgasing of
> contaminants in the tube/cesium supply.

That was my initial guess, but it sounded like it didn't help when he left
it in standby mode with the Cs oven powered down.  That argues in favor of
plain old envelope leakage, unless there's some other mechanism I'm not
thinking of.  It makes sense to verify the current first.

-- john, KE5FX



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Re: [time-nuts] Maximizing Cs Tube Life

[John Miles]

You're right, at 11 ua, that 5071A is pretty much hosed.  I'd be surprised
if it knows what day it is.  You'd better cut your losses and send it to me
before it gets any worse.  Cesium is a hazardous material, not that there's
much left in this particular unit, and you don't want to be stuck having to
throw anything away that contains it.  There's all sorts of red tape, up to
and including EPA fines and prison time.  That said, I could reimburse the
cost of shipping, to defray the inevitable expenses associated with
disposal.  Do you take PayPal?

Seriously, the manual says 0-40 uA is the 'typical' range, so I wouldn't be
inclined to worry about it.  It could be an artifact of the high-performance
tube, for that matter.  You might open the unit up and measure the current
yourself, to make sure the monitoring circuit isn't lying to you for some
reason.

Looks like pages 68 and 127-129 of the service manual .pdf cover ion-pump
supply verification.  Have you tried those procedures yet?

-- john, KE5FX

> -Original Message-
> From: time-nuts-boun...@febo.com [mailto:time-nuts-boun...@febo.com]on
> Behalf Of aceamuseme...@mchsi.com
> Sent: Friday, July 10, 2009 7:58 PM
> To: Discussion of precise time and frequency measurement
> Subject: Re: [time-nuts] Maximizing Cs Tube Life
>
>
>
>
>  I have a similar question I have 2 hp 5071a and I purchased one
> new in the box never opened and one used.both have been in
> operation over a year, the new one high perf tube new style tube
> US4240 started out in storage for two years before I plugged it
> in for the first time..the pump went right down to .2 -.4ua as
> normal but as time has gone by it has risen (lineraly) to almost
> 11.0uA (I think this may not be good). the elect mult volts on
> this tube started out about 1500 and droped within 6 months to
> 1150 and has stayed there.
>
> my other used unit has a pump current of 0.0 or 0.2 all the time
> and a mult of 1430 (stays steady also)been like that for months
> but the new unit continues to rise(pump current).have tried
> turning off the cs oven and leaving on the pump but with no avil
> is this new tube heading twd an early death?
>


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Re: [time-nuts] Maximizing Cs Tube Life

[John Miles]

>
> I have a 5061A and 5061B and both have a position on their front
> panel MODE
> switch that is CS OFF.  When in this position the CS OVEN is off, the OSC
> OVEN is on, the ION PUMP is working and there is signal out (10
> MHz, 5 MHz,
> 1 MHz, 100 KHz, as appropriate) as measured by the CIRCUIT CHECK meter.
>
> Is the 5062C different?  Is there something I am missing here?  I
> guess I do
> not understand the need to 'add a switch' unless it is the desire to only
> run the ION PUMP and the OSC OVEN but not the OSC or anything else.

Right; there was no CS OFF switch on the 5062C.  You can open the loop, but
that's it.  I could have run the ion pump supply from the rear panel, but
that would have taken a separate power supply, and would have left the
crystal oven cold.

It sounds like the switch I added does essentially the same thing as the one
you're talking about.  In your case you could maximize tube life by leaving
that switch set to CS OFF except when needed.  That doesn't answer the
question of how long the Cs tube needs in order to meet specs, but
presumably the manual would...?  I'd be curious to hear the answer myself.

> The one thing I have noticed is the incredible stability of the crystal
> oscillators for weeks at a time as compared to my Thunderbolt.
> On the order
> of 0.1 Hz at 10 MHz after a week.

The Thunderbolt should be in that ballpark (being only 1E-8 per week) when
undisciplined, and of course much better when GPS-locked.  A good OCXO, when
not locked to anything else, should stay put to the tune of 1E-10 to 5E-10
per day.

The HP 10543 oscillator in my 5062C had a bad case of near-constant phase
jumps, so I have a Wenzel Timekeeper-class unit in there now, plus an x2
doubler to get 10 MHz out the front panel.  I'm not sure I have the loop
bandwidth optimized for it yet, but at least it locks up nicely and doesn't
jump.

-- john, KE5FX



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Re: [time-nuts] Maximizing Cs Tube Life

[John Miles]

Many standards have a rear-panel jack for a dedicated ion-pump supply, which
can be left powered up 24/7.  If you run the ion pump continuously, but not
the Cs oven, the tube will presumably last forever.

I added a switch to my 5062C that allows me to leave it plugged in with the
ion pump and OCXO running, but little else.  When I want to stabilize the
OCXO, I flip the switch and wait 10-15 minutes while the Cs oven comes up to
its operating temperature.  This seems to be working well so far.

I don't know exactly how long the Cs oven needs to operate before the final
stability specs are reached, but I'd be surprised if it took more than an
hour or two.  Since the OCXO runs all the time, I would think I'd see some
control-voltage drift if the Cs tube took longer than that to warm up, but I
haven't noticed any to date.

This setup is fairly new and I'm still working on characterizing it, so
don't take any of the above as gospel.  Also, most Cs standards are several
times more stable than the 5062C, and they may need (much) more time to
reach their specs.  Waiting a week before doing anything hardcore is
probably smart.

-- john, KE5FX

> Hello Time-nuts,
>
> Just wondering what the group concensus might be concerning maximizing Cs
> tube life.  On one extreme, if a tube is not used at all it will lose its
> vacuum.  That is why Symmetricom instructs that stored tubes be
> powered for
> at least 30 minutes each 6 months.  At the other extreme is powering the
> tube 24/7 which depletes the Cs source.
>
> In the middle is the question of how long does it take to achieve
> satisfactory stability to use the unit to evaluate other devices
> (oscillators - xtal or Rb).
>
> I would like to maximize the tube life and only need to do evaluations
> periodically.  My first inclination is to fire up the cesium a
> week or so in
> advance of use and then shut it down until needed again.
>
> Just wondering what the time-nut collective experience might be?
>
> Regards,
> Skip Withrow
>
>
>


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Re: [time-nuts] Glitches in data

[John Miles]

That doesn't look like a GPIB interface bug to me.  Those usually involve
duplicating or dropping data rather than arbitrarily turning multiple ASCII
digits into others.  Given the nature of those outliers I'd suspect a
problem with the calculations made by the counter itself.

Although: the later GPIB-USB and GPIB-LAN firmware is a pretty important
update for some instruments, due to a change made in the way the bus pullups
are used.  If you are using either of these adapters, you should make sure
you have the latest update installed.

-- john, KE5FX


> Hi
>
> I've had the same thing happening with a Prologix Ethernet setup until
> firmware 1.5.1.0.
> -Henry
>
> -Original Message-
> From: time-nuts-boun...@febo.com [mailto:time-nuts-boun...@febo.com] On
> Behalf Of Hal Murray
> Sent: Wednesday, July 08, 2009 7:17 PM
> To: time-nuts@febo.com
> Subject: [time-nuts] Glitches in data
>
> I've got an HP 5334B collecting data via a Prologix USB setup.  It's
> been
> running for months.
>
> Mostly, it's doing what I expect.  But then I got 2 glitches in the last
> two
> days.
>
> Here is a graph:
>   http://www.megapathdsl.net/~hmurray/time-nuts/Drift-ocxo3mhz-d.gif
>
> Here is the raw data:
>
> It's the 2.999... column.  The second column is seconds in the day day.
> They
> are 5 minutes apart.
>
> 55019 65824.624 F +2.996881E+06 F +3.2768070130E+04
> 55019 66124.710 F +2.996881E+06 F +3.2768070725E+04
> 55019 66424.796 F +2.996880E+06 F +3.2768071164E+04
> 55019 66724.882 F +2.997045E+06 F +3.2768071592E+04 <==
> 55019 67024.968 F +2.996878E+06 F +3.2768072178E+04
> 55019 67325.054 F +2.996878E+06 F +3.2768072586E+04
> 55019 67624.140 F +2.996880E+06 F +3.2768073011E+04
> 55019 67924.226 F +2.996881E+06 F +3.2768073466E+04
>
> 55020 61924.265 F +2.996883E+06 F +3.2768068930E+04
> 55020 62224.351 F +2.996884E+06 F +3.2768069393E+04
> 55020 62524.437 F +2.996882E+06 F +3.2768069919E+04
> 55020 62824.523 F +2.997030E+06 F +3.2768070314E+04  <==
> 55020 63124.609 F +2.996885E+06 F +3.2768070508E+04
> 55020 63424.695 F +2.996885E+06 F +3.2768070907E+04
> 55020 63724.781 F +2.996878E+06 F +3.2768071254E+04
> 55020 64024.867 F +2.996879E+06 F +3.2768071523E+04
>
>
> Does anybody have any suggestions for what is causing things like this?
> Or a
> checklist of things I should consider?
>
> Everything is plugged into the same outlet.  The OCXO is powered by a
> wall
> wart.
>
> I wasn't near it at either time.
>
> My UPS didn't see any power glitches at either time.  (They are not
> running
> off the UPS.  For this, I'm just using it to monitor power.)
>
>
>
>


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Re: [time-nuts] 10811 crystal orientation

[John Miles]

The nice thing about the amplifier circuits that Bruce has been modelling
lately is the performance they can achieve using ordinary
2N3904/2N-class bipolars, with no exotic hardware or twitchy parameter
dependencies.  There is some work in progress now that will make
inexpensive, plug-and-play isolation/distribution amps available to any who
are interested, with S12 and additive-PN performance competitive with the
best commercial and NIST designs.

-- john, KE5FX

> -Original Message-
> From: time-nuts-boun...@febo.com [mailto:time-nuts-boun...@febo.com]on
> Behalf Of WB6BNQ
> Sent: Wednesday, July 08, 2009 5:49 PM
> To: Discussion of precise time and frequency measurement
> Subject: Re: [time-nuts] 10811 crystal orientation
>
>
> Hi Bruce,
>
> Well, I am glad you are not mad at me.
>
> As you know most humor is fact based and such is the case I made
> about the humor.  I really
> do not have the in-depth knowledge that I should have when it
> comes to deciding which
> "transistor/opamp/comparator" part would be best.  Particularly
> when the discussion starts
> getting heavy in the finer art of noise and phase disturbances and such.
>
> However, I never felt I could NOT approach you with such
> questions.  Hopefully, no one took
> it otherwise.
>
> BillWB6BNQ
>
>
>


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Re: [time-nuts] Lady Heather Display Question....

[John Miles]

Once Mark gets his latest .c file ready, I'll see about adding some Nixie
digits to it.  It could make sense, now that local time display options are
being added.

-- john, KE5FX

> -Original Message-
> From: time-nuts-boun...@febo.com [mailto:time-nuts-boun...@febo.com]on
> Behalf Of Michael Baker
> Sent: Saturday, July 04, 2009 7:07 AM
> To: time-nuts@febo.com
> Subject: [time-nuts] Lady Heather Display Question
>
>
> Hello, Time-Nutters
>
> A question about possible software modifications
> to the Lady Heather display:
>
> Looking at the LH display, I see a large empty
> (black background) area on the left side of the
> screen, between the top of the graph area and
> the bottom of the list of satellites being tracked.
>
> When the cursor is placed in the graph area, a line
> appears in that large empty space that indicates
> the time where the cursor is sitting.
>
> Other than that, it is just a large empty space
> in the display.
>
> Is this space being used (or reserved) for something
> I don't know about?
>
> Is there some reason why a running time display
> with, say-- inch-high digits, could not be placed
> in that area?  Something that could be clearly
> read from across the room?
>
> Thanks--
>
> Mike Baker
> ---
>
>


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Re: [time-nuts] Ideas for a long-wave receiver sought

[John Miles]

It's not necessarily inexpensive, but here's one data point: an EVAL-AD7760
board is $150, and a Nexys2 FPGA board is $129.  This combination can
acquire DC-1 MHz with 100 dB SNR and 120 dB SFDR.  There is no need for a
hardware or FPGA-based DDC, as any modern PC can do host-based processing at
these rates without breaking a sweat.

In the setup I have been playing with, the FPGA is used only to transfer the
AD7760's output to the USB 2.0 chip.  With a 16 KB block-RAM FIFO in the
FPGA and overlapped reads from the CyUSB driver, my test app has run for 2-3
days at 10 MBytes/sec without missing any samples.  At 20 MBytes/sec,
sending every 32-bit sample twice as a test, the FIFO overruns every couple
of hours.

Considering that you can spend $279 on a high-end sound card without trying
very hard, the AD7760-based USB digitizer isn't too unreasonable, at least
for single-channel applications.  I'm still debating whether to spin a PCB
that'll put the FX2 USB chip, FPGA, and AD7760 on one board... it's
tempting, because I'd really like a two-channel digitizer, but it won't
necessarily be much cheaper than the Nexys2/EVAL-AD7760 combo.  The Nexys2
is a real bargain.

I'm not quite ready to call the Verilog and ADC API code "done," although
anyone who wants to play with it is welcome to it, just write me offline.

TI also has a new 24-bit sigma-delta ADC called the ADS1675 that digitizes
at 4 MS/s and uses about half the power of the AD7760.  You can buy the
chips from DigiKey but there appears to be no official evaluation board yet.
It's hard to compare the specs on an apples-to-apples basis, but my
impression is that the overall performance isn't too far behind the AD7760
at 2.5 MSPS.

Re: the SDR-IQ, yes, it comes with a public interface spec.  It's based on
ASCP (Amateur Station Control Protocol), which I'm not too familiar with.
Great little box, usable as a general-purpose digitizer for narrowband HF
applications that don't need to go all the way down to DC.

-- john, KE5FX

> -Original Message-
> From: time-nuts-boun...@febo.com [mailto:time-nuts-boun...@febo.com]on
> Behalf Of Lux, James P
> Sent: Monday, June 22, 2009 9:13 AM
> To: bro...@pacific.net; Discussion of precise time andfrequency
> measurement
> Subject: Re: [time-nuts] Ideas for a long-wave receiver sought
>
>
> 200kHz is a bit tricky for the top end.. That probably puts the
> standard music recording A/D out of the picture (although they
> have very high performance A/Ds in them, and because of large
> production volume, they're relatively inexpensive).
>
> Almost any PC these days has enough processor to take a 400 ksps
> stream of samples and filter/decimate it.
> Maybe the boards from the HPSDR folks might serve?
>
> Do you need continuous stream of samples? One of the eval boards
> for high performance A/Ds with a USB might work for you, but last
> time I checked, they were more oriented to "capture a buffer,
> then analyze" sorts of approaches.
>
> Your best long range approach might be to use a high quality A/D
> with a small FPGA behind it that implements a digital down
> converter, feeding the (lower rate after
> downconversion/filtering) samples through USB to an application
> like DL4YHF's spectrum lab.  DL4YHF is very interested in VLF
> receiving, and he might have good ideas on inexpensive approaches.
> http://freenet-homepage.de/dl4yhf/spectra1.html
>
>
>
>
> > -Original Message-
> > From: time-nuts-boun...@febo.com
> > [mailto:time-nuts-boun...@febo.com] On Behalf Of Brooke Clarke
> > Sent: Monday, June 22, 2009 7:18 AM
> > To: Discussion of precise time and frequency measurement
> > Subject: Re: [time-nuts] Ideas for a long-wave receiver sought
> >
> > Hi Marc:
> >
> > The SDR-IQ has the ability to record everything between 500
> > Hz and 190 kHz when used with a fast enough PC.  This is the
> > best of the SDR series for use below 200 kHz.
> > It can be used with SpectraVue or Winrad.
> > Works with I2PHD WINRAD, SM5BSZ LINRAD, HOKA and DRM software.  See:
> > http://www.rfspace.com/SDR-IQ.html
> > http://groups.yahoo.com/group/SDR-IQ/
> >
> > Have Fun,
> >
> > Brooke Clarke
> > http://www.prc68.com
> >
> > Marc Balmer wrote:
> > > Hi
> > >
> > > I want to build a small, cheap, yet precise long-wave
> > receiver which
> > > can be tuned from the computer in the 2KHz - 200 KHz range (the
> > > intended use is to receive various time signal stations).
> > >
> > > Does a chip for such a receiver exist?  Should I take the SDR route?
> > > I designed a DCF77 receivers some years ago, but I need
> > something more
> > > flexible (and a bit more modern...)
> > >
> > > - Marc Balmer
>
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Re: [time-nuts] OT favorite signal generator?

[John Miles]

No distortion at low levels will occur with any signal generator worth
owning.  Nothing from HP will do that.

-- john, KE5FX

> -Original Message-
> From: time-nuts-boun...@febo.com [mailto:time-nuts-boun...@febo.com]on
> Behalf Of optoma...@rogers.com
> Sent: Friday, June 19, 2009 6:39 AM
> To: Discussion of precise time and frequency measurement
> Subject: Re: [time-nuts] OT favorite signal generator?
>
>
> Hey Robert
>
> Great tip about the attenuator.
>
> I looked up some models on the internet and some look fairly expensive.
> I know that I will always be injecting low voltage signals, do you think
> it would be wise to buy a cheaper fixed attenuator, let's say 20dB?, and
> then just depend on the variable rate that the signal generator?
>
> Thanks-Patrick
>
> Robert Darlington wrote:
> > I just bought an HP 3325A synthesizer/function generator that I
> really like
> > (for some things anyway) in about that price range.   What you get is
> > probably dependent on what YOU need though.  This thing is
> pretty limited
> > but this particular one has the high voltage option so the
> output goes up to
> > 40 volts up to 1MHz.   It only goes to 20. Mhz (at up to 10V I
> > think) but for 99% of what I do that's just fine.  It has a
> 10MHz external
> > reference which I hook to either an Rb osc or a Thunderbolt depending on
> > what I'm doing.  It's pretty neat to see all the digits match
> between the
> > 3325A and the 5335A counter.  Of course, that's being clocked
> by the same
> > oscillator too.
> >
> > Also, I noticed on some signal generators, dropping the output
> down to a few
> > mV distorts the signal.  What I learned to do was send my signal out at
> > about 1 volt ((RMS or p2p, doesn't matter) and go through a
> step attenuator
> > to drop it back down so it comes out clean.
> >
> > -Bob, N3XKB
> >
> > On Fri, Jun 19, 2009 at 6:04 AM, Patrick  wrote:
> >
> >
> >> Hey everyone
> >>
> >> Sorry for the off topic post. I have received great advice in the past
> >> with items for my little shop and I can't resist to ask again.
> >>
> >> I am thinking about buying a signal generator. I suspect that I will
> >> mostly use it to inject low uV/mV signals into the amplification stages
> >> of the laboratory instruments I service.
> >>
> >> Any feedback you have would be greatly appreciated-Patrick
> >>
> >> ___
> >> 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] OT favorite signal generator?

[John Miles]

Budget?  Freq range?

HP 8657As are good general-purpose SGs.  Reliable, serviceable, and
reasonably clean.  Avoid 8656s and 8660s IMHO unless you can get one for
next to nothing.

If you don't mind getting your hands dirty there have been some inexpensive
8662As on the surplus market lately.  They are cleaner than most, have an
actual tuning knob, and include sweep capability.  They are complex,
sometimes maintenance-intensive, and very hard to ship safely, and many of
the ones you find on eBay have lived hard lives.

-- john, KE5FX


> Hey everyone
>
> Sorry for the off topic post. I have received great advice in the past
> with items for my little shop and I can't resist to ask again.
>
> I am thinking about buying a signal generator. I suspect that I will
> mostly use it to inject low uV/mV signals into the amplification stages
> of the laboratory instruments I service.
>
> Any feedback you have would be greatly appreciated-Patrick
>


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Re: [time-nuts] HP5370A self test fault characteristics anddiagnosis

[John Miles]

> I have a 5334B and looking at the same signal it seems more stable. From
> memory (I haven't tried it recently) the 5370 had 3 or 4 unstable low
> order digits. Even selecting high periods or sample size didn't seem to
> remove noise out of two or three digits.
>
> I never used a 5370 before, but this doesn't seem right. I get several
> random digits even looking at it's own clean 10 MHz external clock. That
> shouldn't be, should it?

The procedure Bruce was describing is basically the jitter test from the
manual, at http://cp.literature.agilent.com/litweb/pdf/05370-90031.pdf (this
is actually the same copy that David Kirkby scanned a few years ago, hosted
by Agilent.)  Follow the directions on page 3-11 and 3-12, and post the
results, especially from step 15.  This jitter figure is usually well under
50 ps in a 5370 that's working properly.

-- john, KE5FX


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Re: [time-nuts] HP5370A self test fault characteristics anddiagnosis

[John Miles]

> On the 5370A part, I recently bought one cheap and it sort of works but
> seems very noisey in its lower order digit readings; clean external ref
> doesn't help. I haven't looked at obvious things like the power supply
> yet, but I'm curious if the group has any thoughts of common problems to
> look for.

What mode are you observing the noise in?  Noisy LSDs on a 5370 are normal
in many cases.

-- john, KE5FX


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Re: [time-nuts] Lady Heather question

[John Miles]

Usually LH will time out and give you an error message if the port selection
is the only problem.  I'm not familiar with the NTGS50AA, but given that
it's also from Trimble, my guess is that its TSIP implementation is at least
somewhat different from the Thunderbolt's, and that TBOLTMON knows how to
deal with those differences while LH doesn't.  If you're able to get to the
bottom of the issue, let Mark and/or myself know and maybe we can work
around it.

-- john, KE5FX

> -Original Message-
> From: time-nuts-boun...@febo.com [mailto:time-nuts-boun...@febo.com]on
> Behalf Of erniepe...@aol.com
> Sent: Thursday, June 18, 2009 1:13 PM
> To: time-nuts@febo.com
> Subject: Re: [time-nuts] Lady Heather question
>
>
> HI Murray,
>
> got the same problem and found that the program looks as default
> COM1 port...
> Please chk and change port.
>
> Rgds Ernie.
>
>
> -Original Message-
> From: Murray Greenman 
> To: jmi...@pop.net; hol...@hotmail.com
> Cc: time-nuts@febo.com
> Sent: Thu, Jun 18, 2009 8:45 pm
> Subject: [time-nuts] Lady Heather question
>
>
>
> John/Mark,
>
> I don't own a Thunderbolt, but I do have a very nice Trimble NTGS50AA
> GPSDO which works very well, and it also operates very nicely with
> TBOLTMON, in both TSIP and SCPI modes.
>
> However, I've just fired up Lady Heather V2.0 for the first time, and
> although the program starts, nothing happens. I have a graph graticule
> at the bottom, and a blank black area above with just a few things
> written on it, such as the graph legend. No sign of the wealth of data
> shown in the help file screen shot, nor any graph data, even after
> waiting quite a while.
>
> I tried both the Win version and the DOS version, and they behave the
> same. My test computer is an old IBM Aptiva with 450MHz 586 processor,
> running Win XP. I use COM2 and the program seems happy with that, and
> everything works fine with TBOLTMON.
>
> My next step is to drag out a laptop and spy on the comms between the
> computer and GPSDO to see what's going on (if anything). I know this is
> a big ask, but any suggestions as to what might be happening?
>
> 73,
>
> Murray ZL1BPU
>
>
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>
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Re: [time-nuts] Z3805 initial behaviour after power up

[John Miles]

> Since I do not have an manual for the Z3805: Can any of you Z3801 owners
> second this behaviour to be normal or would you think that it is kind of
> special for the Z3805 or even a real malfunction (in the sense that the
> OCXO's drift is above the specs in the beginning)?

Any OCXO that has been sitting around for years is likely to undergo rapid
aging when you first bring it up.  It will be so far out of spec that I
wouldn't even bother looking at the loop behavior until it's been running
for a week or two.  Chances are it'll be fine by then.

-- john, KE5FX


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[time-nuts] Datum 9390 firmware

[John Miles]

Has anyone been able to come up with a burnable EPROM image for the new
Datum 9390 firmware that's supposed to fix the GPS day # bug?  Before I
start delving into the phone tree at Symmetricom, I thought I'd ask if
anyone who's received one of the new EPROMs has read it yet.

-- john, KE5FX


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Re: [time-nuts] Lady Heather DOS version

[John Miles]

The DOS version is also included with the Win32 distribution at
http://www.ke5fx.com/heather/setup.exe .  It's called heathdos.exe, and will
appear in your installation directory after running the setup program.  (Of
course the setup program itself has to run under Windows, but if that's a
problem I can upload heathdos.exe to the same http directory.)

-- john, KE5FX

> -Original Message-
> From: time-nuts-boun...@febo.com [mailto:time-nuts-boun...@febo.com]on
> Behalf Of Stanley Reynolds
> Sent: Sunday, June 14, 2009 9:19 AM
> To: time-nuts@febo.com
> Subject: [time-nuts] Lady Heather DOS version
>
>
>
> I can find the win32 version aka "setup.exe" but looking for the
> dos version for 800/600 screen version have an old Compaq laptop.
> I would be glad to host files for both versions if that is OK.
>
> Stanley
>


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Re: [time-nuts] Thunderbolt stability and ambient temperature

[John Miles]

> Rex
>
> your experience with the hot bar is quite common.

Sounds like a pretty reasonable manifestation of the Leidenfrost effect.
The water in contact with the hot end of the bar vaporizes, and the
resulting steam layer (which might be microscopic) does a good job
insulating the bar.  There's nowhere else for the heat to radiate or conduct
to, except towards the cold end of the bar.

-- john, KE5FX


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Re: [time-nuts] HP3048A Fixed

[John Miles]

> Hello,
>
> Re my email on the 3048A software.
>
> I got the unit to work.  I have to start windows 98 in dos mode.
>
> Don't know why but I'm happy with that.
>
> It would be nice to have windows running properly, so if anyone does know
> the answer, that would be great.

Have you tried running the non-option 301 software with the TransEra RMB
emulator?

-- john, KE5FX




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Re: [time-nuts] Sound Cards for locking to GPSDO 10 MHz references

[John Miles]

The concern I'd have with modifying a USB sound card, or any of them for
that matter, is that the glue logic between the ADC and the USB chip may be
designed for a certain relationship between the ADC and USB clocks.  Running
the ADC asynchronously may or may not be robust depending on the assumptions
baked into the gate array.  It might be OK if your app can tolerate
occasional misclocking or dropouts but I'd be reluctant to use a hacked
sound card for anything timing-critical.

I just (last week) got an AD7760 ADC eval board working with the Digilent
Nexys2 FPGA platform, with the EVAL-AD7760 board running from its own 40 MHz
clock.  It will accept an external 40 MHz clock source that, in turn,
wouldn't be hard to derive from 10 MHz.  Way overkill for ultra
low-bandwidth work, but if anyone is looking for a clean digitizer for audio
rates in general, you could do a lot worse than this approach.  Cost isn't
too bad either, at $130 for the Nexys2 and $150 for the ADC7760 eval board.
Of course the big drawback is the lack of any sort of standardized audio
driver on the host side.

If/when I spin a PCB for this project I'll definitely include a 10 MHz
input.

-- john, KE5FX


> -Original Message-
> From: time-nuts-boun...@febo.com [mailto:time-nuts-boun...@febo.com]on
> Behalf Of Jeffrey Pawlan
> Sent: Monday, June 01, 2009 3:08 PM
> To: Discussion of precise time and frequency measurement
> Subject: Re: [time-nuts] Sound Cards for locking to GPSDO 10 MHz
> references
>
>
> Soundcards for USB are poor at best.
>
> I have a set of PCI cards that were previously made by EMU and
> they accept
> external reference input.  They no longer make the model I have
> but perhaps
> they have another PCI card with an external ref input.
>
> I am interested in your modulation technique which allows you to use WSJT.
> Please let me know exactly what you are doing. I also do not know
> how you are
> using 5 milliHertz with WSJT since the group of discrete tones
> occupy more
> bandwidth.
>



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Re: [time-nuts] Picket fence ADEV measurement on 5370 counters

[John Miles]

> I have done picket-fencing for years on my 5370B and never seen this
> problem.
>
> I usually use a 1Hz signal as start and a 10MHz from my house reference
> as the stop.

That seems to work OK on this counter, now that you mention it, except that
I see wraparound from 105 ns to 6 ns rather than the expected waffling
between 100.xx ns and 0.xx ns.

I've been assuming that people will use two 1-pps sources, as in the paper.
Can you try that (easily) to see if the same thing happens on yours within a
few milliseconds of coincidence?

> I clock the HP5370B from a third source (usually the internal OCXO)
> to avoid synchronicity.
>
> I will caution you, that the IEEE488 implementation on the 5370B
> is one of the more interesting I have encountered.
>
> You can easily loose measurements, like what you see, by not being
> ready when the counter is.

This isn't a GPIB issue; it happens in local-control mode as well.  The
counter arms itself every second but the display only changes every other
second.

> You should put the counter in talk mode, and have the computer
> continuously
> in read mode to prevent this.
>
> Also, you should timestamp the measurements in the computer with
> fractional second granularity

Sure.  That wasn't from the ADEV program, it's just a dump from an existing
5370b.cpp console app that illustrates the problem. I'm pretty sure at this
point that there's something weird going on with the counter itself.  Would
be curious to know if it's true of other 5370s when feeding both A and B
from 1-pps sources.

-- john, KE5FX




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[time-nuts] Picket fence ADEV measurement on 5370 counters

[John Miles]

Further to this:

> I'm not sure it's possible to make continuous stability
> measurements (Allan
> deviation, etc.) directly with a 5370 since they don't support
> running/overlapped measurements between readings.  If you can work with a
> 1-pps output and can provide a divider for your reference, it can be done
> with a picket-fence technique (e.g.
> http://horology.jpl.nasa.gov/papers/picket_uffc.pdf ) which I
> haven't tried
> yet.
>
> If anyone thinks it might be worthwhile, I could throw together a GPIB app
> to implement Greenhall's paper for the 5370B with a Prologix or
> NI board...
> but my guess is that most people have been using other gear for
> that sort of
> thing.

So, having just received and built two TADD-2 dividers (which look and work
great!), I started to look at the Greenhall paper in more detail today, with
an eye towards getting some picket-fence code running for the HP 5370B.  It
seems easy enough to implement, but there are a couple of things I don't
understand about the process.

1) Why all the math?  This should be a trivial algorithm, you just fetch
successive A-B time intervals from the counter and scale the intervals
directly into relative phase between source A and reference B.  Instead,
Greenhall describes a more complex unfolding algorithm that resembles a
forward-differencing technique with a fudge factor (lambda-Z), whose purpose
is ostensibly to "follow large, slow changes in (the beatnote interval
times)."

This makes little sense because if the beatnote ever drifts too close to the
picket phase from the reference, the counter will start to miss edges
regardless of what the software does.  Any practical use of the picket-fence
algorithm with drifting 1-pps sources would be limited to total runtimes
less than the amount of time needed for the sources to drift into phase with
each other.  That wouldn't be a big problem in practice -- two 10 MHz
sources 100 Hz apart would take over one day to complete a phase crossing,
and (presumably) nobody would try to measure reference/DUT sources that far
apart.

2) Something peculiar that my 5370B does: when the A-B time interval is
about 60 milliseconds either side of coincidence, the counter fails to
report a measurement at every other second.  E.g.:

Sat May 30 06:37:47 2009 TI = 9.48645886170E-01
Sat May 30 06:37:48 2009 TI = 9.48645890060E-01
Sat May 30 06:37:49 2009 TI = 9.48645893870E-01
Sat May 30 06:37:50 2009 TI = 9.48645897320E-01
Sat May 30 06:37:51 2009 TI = 9.48645901190E-01
Sat May 30 06:37:52 2009 TI = 9.48656259040E-01
Sat May 30 06:37:53 2009 TI = 9.48756252730E-01
Sat May 30 06:37:54 2009 TI = 9.48856246600E-01
Sat May 30 06:37:55 2009 TI = 9.48956240020E-01
Sat May 30 06:37:56 2009 TI = 9.49056233810E-01
Sat May 30 06:37:58 2009 TI = 9.49256221440E-01
Sat May 30 06:38:00 2009 TI = 9.49861762440E-01
Sat May 30 06:38:02 2009 TI = 9.51787261680E-01
Sat May 30 06:38:04 2009 TI = 9.53785271190E-01
Sat May 30 06:38:06 2009 TI = 9.55783280510E-01
Sat May 30 06:38:08 2009 TI = 9.57781289960E-01

I'd expect some invalid behavior as the edges come into coincidence with
each other, but I wouldn't expect that behavior to show up at time scales in
the milliseconds, since the 5370's minimum time-interval spec is 10
nanoseconds.  This happens in both +TI and +/-TI modes.  Maybe I have a
calibration problem, or maybe I just need to re-familiarize myself with the
5370's interpolator mechanism... but either way, it seems that there are
going to be problems with any picket-fence implementation if the edges are
allowed to approach coincidence.  Whether this happens at margins of 10
nanoseconds or 100 milliseconds, it will hose any attempt at continuous data
collection.

One workaround would be to synthesize the missing values by lerping between
any reports received at two-second intervals... but if I go down that road,
I might as well interpolate between conventional frequency measurements to
simulate a zero-dead-time counter.

So if interpolation between skipped 1-second periods isn't acceptable, the
5370B ADEV program will need to report an error and terminate the
measurement if the time interval readings ever approach the -100 to +100
millisecond zone.  Is that a showstopper for anyone, other than users who
aren't able to tweak the phase of either of their 1-pps sources?

-- john, KE5FX



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Re: [time-nuts] HP82335 HPIB Card

[John Miles]

Hmm.  I know I couldn't find an NI PCII/IIA driver for Win2K when I
looked -- it's why I switched to the PCI-GPIB -- but yeah, they do have
drivers for the old AT-GPIB/TNT and others, all the way through WinXP.
Looks like the easiest page to check is
http://zone.ni.com/devzone/cda/tut/p/id/5326 .  Still no NT love for the
PCII/IIA, so I guess it's time to let go of that one.

-- john, KE5FX


> Not so. I just went through this. Even the older ISA NI GPIB cards will
> work on XP with the right drivers.
>
>


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Re: [time-nuts] HP82335 HPIB Card

[John Miles]

Many of those older ISA GPIB cards never had Windows NT drivers written for
them, much less 2K/XP.  That's true of National Instruments, and wouldn't
surprise me if it's true of HP as well.  I'm guessing you'll need to stick
with Win9x if you need to use that card.  (You don't have to go all the way
back to Win95, as Win98SE will use the same drivers.)

-- john, KE5FX

> -Original Message-
> From: time-nuts-boun...@febo.com [mailto:time-nuts-boun...@febo.com]on
> Behalf Of Martyn Smith
> Sent: Thursday, May 28, 2009 10:43 AM
> To: time-nuts@febo.com
> Subject: [time-nuts] HP82335 HPIB Card
>
>
> Hello,
>
> I'm trying to get a 82335 HPIB card to run on my computer.
>
> The card works in an old computer running windows 95, so I know
> the card is
> ok.
>
> I have a Pentium 3 running windows XP home edition.  This computer has an
> ISA connector, so the HPIB fits ok.
>
> But the computer just doesn't recognize my HPIB card.
>
> Can anyone help.
>
> It may be that windows XP is too new to run on this computer.
> The ISA connector is actually on a cage that plugs into a PCI
> base, so I'm
> wondering if that's a problem as well.
>
> Any advice will be much appreciated.
>
> I have just bought win95 on eBay, and I'm going to try that when
> it arrives.
>
> Best Regards
>
> Martyn
>
>


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Re: [time-nuts] 5070B once more.... (actually electrolytics)

[John Miles]

I just had a set of 3 paralleled electrolytics more or less explode on an
nVidia video card.  Some further poking around, however, revealed that they
were damaged due to a drain-source short in the buck regulator they were
supposed to filter.  The three 5V caps ended up with 12V across them.  So it
isn't *always* the electrolytics that are to blame!

-- john, KE5FX

> -Original Message-
> From: time-nuts-boun...@febo.com [mailto:time-nuts-boun...@febo.com]on
> Behalf Of g4...@g4fre.com
> Sent: Saturday, May 23, 2009 6:30 AM
> To: time-nuts@febo.com
> Subject: Re: [time-nuts] 5070B once more (actually electrolytics)
>
>
> I just got hit by this issue in my Dell GX270. Its the one i use for HPIB
> instruments/Heather. The video output disappeared. Doing a web search i
> found lots of posts on they used faulty capacitors. They didnt do
> a recall
> as it would lead to "bad customer perception of Dells quality" (they had
> just done a battery recall).
>
> Upon examination 2 had "bulged" You can get kits to replace all 18
> electrolytics. It may explain why there are a lot of
> gx260/270/280 unsold on
> ebay recently
>
> Dave
>
>
>


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Re: [time-nuts] 5070B once more....

[John Miles]

> Has anybody tried to replace these
> fans with a
> more modern type (12/24 volt). I'm sure the designers were being very
> proper, but I cannot believe that a counter should require such a large
> volume of air moving through it ?
> I have an EIP 545 Counter and
> an HP 5335A
> which both have Papst fans and are very noisy
> Any ideas on this.
> Roy

The 5370 counters are unusually power-hungry, at about 160 watts for my
5370B.  The airflow through the instrument is where the noise is coming
from, not so much the fan itself (try powering the fan up outside the
counter, holding it in your hand, and it'll be much quieter).  Can't speak
for EIP but I don't think it's a good idea to alter the factory airflow
specs on HP gear, in most cases.

>Now I'm wondering which software I could use to grab data from it to the PC
>and then to analyze the buffers to see the stability of my rubidium
>source synchronised with the 1pps coming from the GPS.

I'm not sure it's possible to make continuous stability measurements (Allan
deviation, etc.) directly with a 5370 since they don't support
running/overlapped measurements between readings.  If you can work with a
1-pps output and can provide a divider for your reference, it can be done
with a picket-fence technique (e.g.
http://horology.jpl.nasa.gov/papers/picket_uffc.pdf ) which I haven't tried
yet.

If anyone thinks it might be worthwhile, I could throw together a GPIB app
to implement Greenhall's paper for the 5370B with a Prologix or NI board...
but my guess is that most people have been using other gear for that sort of
thing.

-- john, KE5FX


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Re: [time-nuts] 5370B Designer Dave Chu retires from Agilent

[John Miles]

Not to mention his work with the 5345A, another perennial favorite around
here.  /raises beer

-- john, KE5FX

> -Original Message-
> From: time-nuts-boun...@febo.com [mailto:time-nuts-boun...@febo.com]on
> Behalf Of Rick Karlquist
> Sent: Tuesday, May 19, 2009 6:56 PM
> To: Discussion of precise time and frequency measurement
> Subject: [time-nuts] 5370B Designer Dave Chu retires from Agilent
>
>
> After 46 years at HP/Agilent, Dave Chu, the father of the 5370 series
> has retired.  It is nice to see Time Nuts keeping these wonderful
> instruments going.
>
> Rick Karlquist N6RK
>
>


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Re: [time-nuts] HP 5370B vs SR620

[John Miles]

> As to the socket issue, my 5370A has been dead reliable.  No problems at
> anytime.
>
> I think your socket issue is unique to your unit, or perhaps the
> series your
> unit came from.

I've heard of socket failures happening on at least one 5370A besides
Didier's, but I don't think it's reached pandemic proportions yet.  Seems
that the socket manufacturers didn't really understand their own reliability
figures back then.  I've been bitten by them myself -- not by my 5370, but
by the Apple II+ I had as a high-school kid, which used similar DIP sockets
on every chip.

My guess is that the gold-plated machined-pin sockets will be fine for the
duration.  The pins probably saw enough tinning during soldering, and if
not, you can just reheat them later if needed.  So far, I've seen problems
with gold-to-copper solder joints only in cases where the rule against
making a physically-stressed solder connection has been violated.  The 8662A
is prone to those problems because HP failed to use pigtails to connect
their SMC center pins to the PC boards.  A bigger problem with the
machined-pin DIP sockets is that they can let go of their chips if subjected
to vibration in some orientations, another fun phenomenon that the
manufacturers don't seem to talk about.

5370s are nice boxes but they can be a challenge to work on.  There are a
couple of editions of the service manual, both apocryphal at best.  One
concern is that the interpolators are hard to calibrate properly without an
8082A pulse generator (read: I'm not sure how you'd even attempt it.)

-- john, KE5FX


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Re: [time-nuts] Lady Heather version 2.0 now available

[John Miles]

One odd thing about your (Mark's) messages is the behavior of the ones that
have Hotmail advertising footers with URLs pointing to Windows Live.
Although they seem to come through as plaintext, clicking anywhere in the
body of the message (as when I want to bring the message window to the
foreground so I can read it) activates the URL link.  I then have to close
the resulting Firefox tab.

I guess it's some kind of hack on the part of Microsoft to artificially
increase apparent clickthrough ratios.  I've never seen it happen with mail
from anyone else.  It's possible that the time-nuts archiver is having
problems with whatever technique is used to turn the whole message body into
a live link.

(Obviously, messages that have gone through the listserv no longer behave
that way; it's just something I've noticed in messages between us offline
while working on Heather releases.)

-- john, KE5FX

> -Original Message-
> From: time-nuts-boun...@febo.com [mailto:time-nuts-boun...@febo.com]on
> Behalf Of Mark Sims
> Sent: Tuesday, May 12, 2009 2:28 PM
> To: time-nuts@febo.com
> Subject: [time-nuts] Lady Heather version 2.0 now available
>
>
>
> Hmmm,  problem seems to be with the time-nut archives.  I usually
> read messages via the archives,  and the messages are either
> blank or clipped off there.
>
> ---The all appear to be
> getting through from here Mark.
>
> -Original Message-
> From: time-nuts-bounces at febo.com [mailto:time-nuts-bounces at
> febo.com] On
> Behalf Of Mark Sims
> Sent: 12 May 2009 17:30
> To: time-nuts at febo.com
> Subject: [time-nuts] Lady Heather version 2.0 now available
>
>
> Lets try it again without any spaces...mayby it will get by MicroCensor:
> _
> Insert movie times and more without leaving Hotmail®.
> http://windowslive.com/Tutorial/Hotmail/QuickAdd?ocid=TXT_TAGLM_WL
_HM_Tutorial_QuickAdd1_052009
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Re: [time-nuts] Worlds smallest pendulum clock (oscillator)

[John Miles]

What are the advantages of these VCMOs versus traditional quartz VCXOs?

-- john, KE5FX

> -Original Message-
> From: time-nuts-boun...@febo.com [mailto:time-nuts-boun...@febo.com]on
> Behalf Of Skip Withrow
> Sent: Monday, May 11, 2009 9:21 PM
> To: time-nuts@febo.com
> Subject: [time-nuts] Worlds smallest pendulum clock (oscillator)
> 
> 
> 
> Check out this device - http://www.sitime.com/products/sit3701.php 
> 
> Wow, a MEMS oscillator that works from 1 to 80MHz.  This sounds like a 
> candidate for constructing the worlds smallest pendulum clock 
> (well I guess 
> more tuning fork than pendulum).  I'm sure some time-nuts have ideas for 
> suitably small displays. 
> 
> Just food for thought. 
> 
> Regards,
> Skip Withrow
> 
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Re: [time-nuts] Lady Heather version 2.0 now available

[John Miles]

I think an extra '.' found its way into that link:
http://www.ke5fx.com/heather/setup.exe 

-- john, KE5FX

> -Original Message-
> From: time-nuts-boun...@febo.com [mailto:time-nuts-boun...@febo.com]on
> Behalf Of Mark Sims
> Sent: Saturday, May 09, 2009 8:39 PM
> To: time-nuts@febo.com
> Subject: [time-nuts] Lady Heather version 2.0 now available
> 
> 
> 
> Lady Heather's GPS Disciplined Oscillator Control Program has 
> been upgraded to version 2.0
> 
> It is available from John Miles' site 
> at:http://www.ke5fx.com/heather/setup..exe
> 
> The new version adds many new features including the ability to 
> view data at different time scales,  calculate HDEVs, MDEVs, and 
> TDEVs (including a mode to display/plot all versions of the adevs 
> at the same time),  read in and write log files,  adjust 
> oscillator disciplining parameters,  zoom in/out on a graph with 
> the click of a mouse,  etc.  DOS mode users can use EMS memory 
> for extended ADEV intervals.
> 
> The new version did change some of the command line parameters 
> and keyboard commands.  You may need to tweak your startup 
> command profile.  You should check the readme file and online 
> help ("heather /?" and "?" from the keyboard) for more info.  
> Also check the change info in heather.cpp for more detailed info 
> on the changes (and a couple of undocumented features).
> 
> Many thanks to John for his Windows port and help.
> 

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Re: [time-nuts] OT: 10 MHz data capture, help

[John Miles]

> It might make sense to layout something on the front section of
> the board.
> As long as that section isn't stuffed it won't get in the way.
> Whatever is
> likely to be most popular.
>
> Does anybody know of an inexpensive FPGA card like that?

Tom eventually went with a USBee SX board.  The manufacturer doesn't say,
but I'm guessing there's a fair bit of RAM on those boards, because they
claim to support continuous streaming at 24 megabytes/second with no data
loss.  As it turned out he had a clock line available for the NRZ bitstream,
so he didn't have to sample at 20 MHz.

I fooled around a bit with a Xylo USB board and was able to recover a
clocked bitstream at 10 MHz, but with only the 512-byte FIFO on the FX2,
there's not much time for Windows to go out to lunch.  It's probably
possible to synthesize a large-enough FIFO in the gate array to make the
process reliable.

> There are a handful of reasons why FPGA and PCI don't play
> together well.
> The main one is that old 5V PCI can generate 11V spikes from
> reflections and
> that is off scale with modern silicon technology, or at least the
> branch of
> it used in the FPGAs that I'm familiar with.

KNJN has been selling their "Dragon" PCI board (
http://www.knjn.com/?pg=cat&src=3 ) for awhile, and it looks like they just
glued the Spartan-2 chip to the bus.  Looks simple enough, if not especially
inexpensive.

They have a habit of not fully documenting their hardware in a way that
allows you to build standalone applications with it, though.  If inspired to
do anything with their hardware, make very sure the documentation is
adequate for the job.

-- john, KE5FX


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Re: [time-nuts] OT: Verilog/VHDL discussion list created...

[John Miles]

> Google didn't do anything to usenet.  They did provide a web based
> interface into usenet, and bought the dejanews archive of all
> non-binary groups.
>

If you were a hardcore DejaNews user, as I was, you were probably not very
happy with the way Google handled the archive and its user interface.  If
you *were* happy with what they did, you're literally the first user I've
encountered who was.

It's neither here nor there, as I prefer email lists to Usenet, and I'm the
one who started the group. :-P

-- john, KE5FX


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Re: [time-nuts] OT: Verilog/VHDL discussion list created...

[John Miles]

> Michael Sokolov skrev:
> > John Miles  wrote:
> >
> >> Not everybody can stomach Google's perversion of Usenet (which
> admittedly
> >> was no small engineering feat in itself).
> >
> > Aren't there still non-Google ways of accessing Usenet?
>
> There is. Find the Wikipedia page for Usenet to find several
> suggestions...
>
> I am really considering it.
>
> But prefering Yahoo over Google usenet is ehum... a bit strange.
>

What objections are there to Yahoo Groups?  I don't have a way to get NNTP
traffic in my email inbox, nor would I want it if I could.

-- john, KE5FX



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Re: [time-nuts] OT: Verilog/VHDL discussion list created...

[John Miles]

>
> At 12:29 PM 4/14/2009 , John Miles wrote:
> >... for those who would like to participate in HDL discussions
> that aren't
> >on-topic for existing lists:
> >
> >http://groups.yahoo.com/group/HDLTalk
> >
> >Any VHDL or Verilog HDL-related topics are welcome.
>
> How will this compare to comp.lang.verilog, comp.lang.vhdl, and
> comp.arch.fpga?

Not everybody can stomach Google's perversion of Usenet (which admittedly
was no small engineering feat in itself).

-- john, KE5FX



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[time-nuts] OT: Verilog/VHDL discussion list created...

[John Miles]

... for those who would like to participate in HDL discussions that aren't
on-topic for existing lists:

http://groups.yahoo.com/group/HDLTalk

Any VHDL or Verilog HDL-related topics are welcome.

To keep spammers away, new member signups require moderator approval.  For
this reason, please indicate your interest(s) briefly when you join.  This
can be as brief as a call sign or company affiliation, just so I can tell
you're not a freelance V14g^a salesman.

-- john, KE5FX


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Re: [time-nuts] OT favorite chip programmer/favorite ROM emulator

[John Miles]

>
> Hi Everyone
>
> Sorry for the off topic post. I have received such great advice in the
> past with regard to instrumentation purchases, I just can't resist. The
> caliber of knowledge on this list is second to none.
>
> I am looking for a low cost chip programmer(under $300, preferably under
> $200). Has anyone had a positive(or negative) experience with a
> manufacturer?


What kind of chip programmer?  Microcontrollers, or PROMs?  If you're
looking for an economical PROM burner, I'll put in a plug for this one:
http://cgi.ebay.com/ws/eBayISAPI.dll?ViewItem&item=290304315635

The seller's been around a long time, and is good to deal with.  The board
itself looks sort of disreputable, but it's actually quite functional, easy
to use, and a real bargain.  The device catalog is decent, if you don't mind
occasionally having to look up equivalent part numbers.  Avoid earlier
versions that used hybrid LPT/USB connections, as they had some problems.

-- john, KE5FX




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Re: [time-nuts] Updated Divider Jitter Results - 74HC390

[John Miles]

> > I believe having STD in parts of 10-14th is fairly respectable for
> > amateur designs..

It depends on whether it's due to the counter or the DUT.  Keep in mind the
5370's own jitter is about 15-20 ps for a best-case unit (and they all seem
to be a bit different).

For an application like an ADC sampling clock, SNR is
20*log(1/(2*pi*freq*jitter)).  In this case the jitter floor is around 10
ps, and you would like to think the device itself is cleaner.  Using that
equation, 10 ps of jitter at 10 MHz puts the SNR at about 64 dB.

That's about the same SNR floor that you'd see if you used a traditional
microwave spectrum analyzer to observe the integrated noise on the same 10
MHz source.  You would never try to use a conventional SA to measure phase
noise on a 10 MHz source, unless you knew from the outset that you had a
really, seriously awful 10 MHz source.  Likewise, you can't use a
conventional time-interval counter to characterize the jitter in the time
domain.  You need a specialized test set, either a very clean
direct-sampling ADC/FFT or another type of baseband PN analyzer.

> >> For a 10,000 sample run, the standard deviation was 12.1 picoseconds,
> >> and the peak-to-peak variation was 70 picoseconds.  Based on
> experiments
> >> I ran a few years ago, I think this is pretty much the noise floor of
> >> the 5370B and the divider could be better than this.

Exactly.  The divider had better be *much* better than that, or it is not
useful for a large number of applications.

The TSC5120 can do residual noise measurements, right...?  That's the better
tool for the job.

-- john, KE5FX




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Re: [time-nuts] Datum 9390 Problems

[John Miles]

I'm still curious to hear if anyone else is seeing the same ~1E-10 error in
their 9390's 10 MHz output.  I don't really care that much about the
front-panel clock, but the fact that it seems to be locking the rubidium
oscillator at the wrong frequency is more of a concern.

-- john, KE5FX

> -Original Message-
> From: time-nuts-boun...@febo.com [mailto:time-nuts-boun...@febo.com]on
> Behalf Of Lasse
> Sent: Thursday, March 26, 2009 8:56 AM
> To: time-nuts@febo.com
> Subject: [time-nuts] Datum 9390 Problems
>
>
>
>Gents,
>I just received a message from the local Symmetricom rep that they ARE
>working on a solution!
>No dates are given but there will be a fix... i.e. new E-Proms.
>Cheers
>Lasse
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Re: [time-nuts] 5062C

[John Miles]

Hmm, looks like there is no problem for domestic shipments but some
potential red tape for international shipments.  Predrag, I'll look into it
a bit and let you know offline if it appears to be feasible to ship it to
you.

-- john, KE5FX

> -Original Message-
> From: time-nuts-boun...@febo.com [mailto:time-nuts-boun...@febo.com]on
> Behalf Of Brian Kirby
> Sent: Monday, March 23, 2009 5:28 PM
> To: Dave Carlson; Discussion of precise time and frequency measurement
> Subject: Re: [time-nuts] 5062C
>
>
> see http://www.agilent.com/metrology/hazardous.shtml
>
> Brian KD4FM
>
> Dave Carlson wrote:
> > Um, John.  Cesium is a Haz Mat. Are you prepared for all the export
> > paperwork to do the shipment?
> >
> > Dave
>


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Re: [time-nuts] 5062C

[John Miles]

No but that's a good question, now that USPS no longer offers a
surface-delivery option.  Are there special forms that need to be filled out
when shipping these things by air?

The tube originally came via air from Australia with no special labelling.

-- john, KE5FX

> -Original Message-
> From: time-nuts-boun...@febo.com [mailto:time-nuts-boun...@febo.com]on
> Behalf Of Dave Carlson
> Sent: Monday, March 23, 2009 3:25 PM
> To: Discussion of precise time and frequency measurement
> Subject: Re: [time-nuts] 5062C
>
>
> Um, John.  Cesium is a Haz Mat. Are you prepared for all the export
> paperwork to do the shipment?
>
> Dave
> - Original Message -
>
> From: "John Miles" 
> To: "Discussion of precise time and frequency measurement"
> 
> Sent: Monday, March 23, 2009 12:53 PM
> Subject: Re: [time-nuts] 5062C
>
>
>
> > John,
> >
> > Is that, now unusable tube  a surplus for You?  I'd have some use
> > for it...
> >
> > (sectioned, as a display for an University lab)..
> >
> >
> > Predrag Dukic
> > University of Split
> > Croatia
>
> Sure, Predrag, you're welcome to it.  Someone might as well get
> some use out
> of it.  Send me your address offline to jmi...@pop.net, and I'll put it on
> the slow boat.
>
> I'm sure you know to be careful opening the tube up, as cesium is nasty
> stuff.
>
> -- john, KE5FX
>
>
>
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>
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Re: [time-nuts] Datum 9390 Problems

[John Miles]

> -Original Message-
> From: time-nuts-boun...@febo.com [mailto:time-nuts-boun...@febo.com]on
> Behalf Of Thomas Folkers
> Sent: Monday, March 23, 2009 12:11 PM
> To: time-nuts@febo.com
> Subject: [time-nuts] Datum 9390 Problems
>
>
>
>On Mar 22, 00:00 UT, both of our Datum 9390 model GPS receivers/time
> code generators started producing erroneous day of year and actual year
> values.
>

Same here, it's day "597" according to my Datum 9390 Rb clock.  The time
appears correct.  Also interesting is the 10 MHz output, which appears to be
about 2E-10 high compared to a Thunderbolt and cesium standard.  That wasn't
the case when I first bought the 9390 a year or so ago, but it's been true
for at least a couple of days now.  There's no indication in the display
that the rubidium's unlocked, as the status remains "Doing GPS correction
(System check OK)".

Anyone else seeing a constant frequency error from theirs?

-- john, KE5FX





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Re: [time-nuts] 5062C

[John Miles]

> John,
>
> Is that, now unusable tube  a surplus for You?  I'd have some use
> for it...
>
> (sectioned, as a display for an University lab)..
>
>
> Predrag Dukic
> University of Split
> Croatia

Sure, Predrag, you're welcome to it.  Someone might as well get some use out
of it.  Send me your address offline to jmi...@pop.net, and I'll put it on
the slow boat.

I'm sure you know to be careful opening the tube up, as cesium is nasty
stuff.

-- john, KE5FX



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Re: [time-nuts] 5062C

[John Miles]

> There's an HP 5062C closing on eBay soon!
>
> Corby
>

Thanks for the heads-up, Corby, even if it incited a bidding war. :)  I
bought it and got it working without much trouble.  The problem turned out
to be a resistor that had drifted high and crowbarred the oven-temp shutdown
circuit.

Its cesium tube is elderly but still has some life in it.  Beam current is
about 0.47V at the test point (or 10 on the front-panel meter) with the
mass-spec voltage at the first peak of 12.0V, and about 0.68V (~12 on the
meter) with the mass-spec voltage at its highest peak, at 17.5V.

Question: the 5062C manual has some contradictory instructions for setting
the mass-spectrometer bias.  Page 4-45 says the adjustment is "correct" when
the beam current is at its lowest-voltage peak.  Page 4-56 says "More than
one peak may be indicated... Set MASS SPEC control for highest peak."  Which
is optimal?  In my case I see a lot more beam current at the 17.5V peak than
at the 12.0V peak, so I'd rather leave it at 17.5.

The bad news is that when I tried installing my spare 5062C Cs tube, which
I'd previously bench-tested successfully, the hot-wire ionizer filament
opened up at some point during the periodic supply-cycling process that
takes place until the ion pump current falls to its normal operating value.
That sucked, because now I'll never know how the bench test results compare
to actual performance in the clock.

I don't see anything I might've done wrong when I installed the other tube.
There was just too much O2 in the envelope, I guess...

-- john, KE5FX


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Re: [time-nuts] Lady Heather display length limitation?

[John Miles]

The /q= command-line argument lets you expand the plot queue size.  Looks
like the default is 86400 entries for one day's worth of data taken at
one-second intervals.

Mark -- at one time it apparently was set to 3 days in the Windows version,
but not now?  Do you remember why it was backed down to one day?  Each entry
takes 24 bytes so I see no reason why it couldn't be cranked up to 100
at least, under Windows.

-- john, KE5FX

> -Original Message-
> From: time-nuts-boun...@febo.com [mailto:time-nuts-boun...@febo.com]on
> Behalf Of Freqtime
> Sent: Tuesday, March 17, 2009 5:35 PM
> To: time-nuts@febo.com
> Subject: [time-nuts] Lady Heather display length limitation?
>
>
> First of all, thanks to the developers of this great program.
>
> Second, is there a limit on the length of time that can be
> retained in memory for the displayed graph? I set the interval on
> 2 separate units to 1 second
>
> and ran them for a few days. Both computers only retained the
> latest day or so of info. I do remember running these same units
> for about the same time before but
>
> with the interval set to 10 seconds and several days were
> retained. I am assuming there is some limitation to actual number
> of measurements retained
>
> in memory.
>
> Regards,
>
> John M


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Re: [time-nuts] Thunderbolt performance vs temperature sensor

[John Miles]

> Hello Said,
>
> Attached is a screen dump of a run that John Miles did.  You can
> see that the envelope of the DAC voltage follows the temperature
> curve (inversely).   On a finer scale the DAC voltage follows the
> PPS error.  This plot was done with the unit locked to GPS.  I
> believe the time scale is 10 secs/pixel (1 hr per major
> horizontal division).

Here's a somewhat-clearer example:
http://www.thegleam.com/ke5fx/day.gif

Each point is 108 seconds, so the entire screen width is about 24 hours.
The yellow temperature and green DAC curves are rather strongly correlated!

-- john, KE5FX




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Re: [time-nuts] HP3048A Phase Noise Test System

[John Miles]

(Sorry, that came across as somewhat snarkier than intended -- point being,
the 3048A software expects to run on an HP controller or an emulator, and
the emulators, in turn, can work only with full-featured GPIB controller
boards.  You're stuck with what the emulator author supports, and there's no
way to make HTBasic talk to a Softmark or even a Prologix board.)

-- john, KE5FX

> -Original Message-
> From: John Miles [mailto:jmi...@pop.net]
> Sent: Monday, March 02, 2009 10:49 AM
> To: Discussion of precise time and frequency measurement
> Subject: RE: [time-nuts] HP3048A Phase Noise Test System
>
>
> Rest assured, you are not going to get the 3048A system (or
> pretty much anything else) working with a Softmark adapter.
>
> -- john, KE5FX
>
>
>
> > -Original Message-
> > From: time-nuts-boun...@febo.com [mailto:time-nuts-boun...@febo.com]on
> > Behalf Of Don Latham
> > Sent: Monday, March 02, 2009 9:14 AM
> > To: Discussion of precise time and frequency measurement
> > Subject: Re: [time-nuts] HP3048A Phase Noise Test System
> >
> >
> > Hardware can be inexpensive. An Australian firm called Softmark sells an
> > USB to GPIB interface on ebay for about $35 or so. I have one, and it
> > works. Software is another problem entirely. If you do not have
> the source
> > code for the Hp program, you will need the manual for the 3048 with all
> > the needed info. I've found the GPIB to be difficult sometimes. The
> > Softmark comes with a dll that can be used with Visual Basic; I'd advise
> > VB6. Good luck.
> > Don
> >
> > Martyn Smith
> > > Hello All,
> > >
> > > I have a couple of HP3048A with option 301 phase noise test sets.
> > >
> > > I run the systems on HP Brio computers with a GPIB interface, running
> > > Windows 95.
> > >
> > > I bought the units as working systems and have no knowledge
> on the 3048A
> > > software and how it works.
> > >
> > > I want to upgrade the system using a laptop with a GPIB interface.
> > >
> > > Has anyone successfully done this?
> > >
> > > Would I need a special GPIB interface and how would I get the
> > software to
> > > talk to the GPIB interface?
> > >
> > > Any help would be much appreciated.
> > >
> > > Best Regards
> > >
> > > Martyn
> > >
> > >
> > >
> > >
> > > ___
> > > 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.
> > >
> >
> >
> > --
> > Dr. Don Latham AJ7LL
> > Six Mile Systems LLP
> > 17850 Six Mile Road
> > POB 134
> > Huson, MT, 59846
> > VOX 406-626-4304
> > www.lightningforensics.com
> > www.sixmilesystems.com
> >
> >
> > ___
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> > and follow the instructions there.
> >


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Re: [time-nuts] HP3048A Phase Noise Test System

[John Miles]

Rest assured, you are not going to get the 3048A system (or pretty much
anything else) working with a Softmark adapter.

-- john, KE5FX



> -Original Message-
> From: time-nuts-boun...@febo.com [mailto:time-nuts-boun...@febo.com]on
> Behalf Of Don Latham
> Sent: Monday, March 02, 2009 9:14 AM
> To: Discussion of precise time and frequency measurement
> Subject: Re: [time-nuts] HP3048A Phase Noise Test System
>
>
> Hardware can be inexpensive. An Australian firm called Softmark sells an
> USB to GPIB interface on ebay for about $35 or so. I have one, and it
> works. Software is another problem entirely. If you do not have the source
> code for the Hp program, you will need the manual for the 3048 with all
> the needed info. I've found the GPIB to be difficult sometimes. The
> Softmark comes with a dll that can be used with Visual Basic; I'd advise
> VB6. Good luck.
> Don
>
> Martyn Smith
> > Hello All,
> >
> > I have a couple of HP3048A with option 301 phase noise test sets.
> >
> > I run the systems on HP Brio computers with a GPIB interface, running
> > Windows 95.
> >
> > I bought the units as working systems and have no knowledge on the 3048A
> > software and how it works.
> >
> > I want to upgrade the system using a laptop with a GPIB interface.
> >
> > Has anyone successfully done this?
> >
> > Would I need a special GPIB interface and how would I get the
> software to
> > talk to the GPIB interface?
> >
> > Any help would be much appreciated.
> >
> > Best Regards
> >
> > Martyn
> >
> >
> >
> >
> > ___
> > 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.
> >
>
>
> --
> Dr. Don Latham AJ7LL
> Six Mile Systems LLP
> 17850 Six Mile Road
> POB 134
> Huson, MT, 59846
> VOX 406-626-4304
> www.lightningforensics.com
> www.sixmilesystems.com
>
>
> ___
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Re: [time-nuts] HP3048A Phase Noise Test System

[John Miles]

Short answer: download an eval copy of TransEra HTBasic (purchasable for
about $1000 US/seat, usable for 30 minutes at a time otherwise).  Then unzip
a copy of the HP RMB software that's been tweaked to make it more compatible
with the emulator, at http://www.ke5fx.com/3048A_X01.zip .  Set up the
emulator according to the readme.txt file.  You can run the emulator with a
National Instruments GPIB board.  I don't know if it works with the HP
interfaces or not.

The docs for the 3048A system itself are at
http://www.hparchive.com/hp_equipment.htm , near the bottom of the table.

This is an arcane, patience-trying process, and not all functions and
features work properly.  But that's how you get to ~-180 dBc/Hz for free!

-- john, KE5FX

> -Original Message-
> From: time-nuts-boun...@febo.com [mailto:time-nuts-boun...@febo.com]on
> Behalf Of Martyn Smith
> Sent: Monday, March 02, 2009 5:06 AM
> To: time-nuts@febo.com
> Subject: [time-nuts] HP3048A Phase Noise Test System
>
>
> Hello All,
>
> I have a couple of HP3048A with option 301 phase noise test sets.
>
> I run the systems on HP Brio computers with a GPIB interface, running
> Windows 95.
>
> I bought the units as working systems and have no knowledge on the 3048A
> software and how it works.
>
> I want to upgrade the system using a laptop with a GPIB interface.
>
> Has anyone successfully done this?
>
> Would I need a special GPIB interface and how would I get the software to
> talk to the GPIB interface?
>
> Any help would be much appreciated.
>
> Best Regards
>
> Martyn
>
>
>
>
> ___
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[time-nuts] Never mind Thunderbolts...

[John Miles]

Can TAPR put together a group buy on these?
http://www.teachspin.com/instruments/optical_pumping/index.shtml

-- john, KE5FX

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Re: [time-nuts] Different Thunderbolt versions

[John Miles]

> I believe that the blue trace (#3) on the last figure from John Miles'
> page [3] is with the integrated 24 to -12, +12, +5 V PSU. So you are
> better off buying a cheap barebones Thunderbolt and a cheap linear PSU.

That's my thinking, assuming the currently-available surplus ones all have
good-quality rocks like the TAPR ones did.  I don't have any basis to
speculate on that, or to assume that all of the older Thundebolts with PIEZO
OCXOs are as unstable (and spur-ridden) as mine was.

My original unit had been in continuous service for over 5 years at the time
I measured it.   Until the TAPR group buy happened, it was the only one I'd
ever used.

-- john, KE5FX


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Re: [time-nuts] Weird Lady Heather behavior observed...??

[John Miles]

> HOWEVER-- if I close the LH display and open it back
> up shortly thereafter, all my T-bolt running parameters
> start fluctuating wildly and going off-scale.  Even the
> yellow temp line goes off scale and PPS OADEV and OSC OADEV
> both drop back to a high e-12.

At what tau values, though?  The idea behind ADEV is that it goes lower the
longer you run.  When you first launch the program, you only have a
short-term history to observe.

>
> It takes about 90 minutes for everything to settle back down,
> after which everything runs tightly for many hours until
> the next time I minimize or close and re-open the LH display.

The graph-recentering behavior can be extremely confusing because it gives
the appearance of jumps that aren't really happening.  Try running with /m=4
to compress the graph height 4x and see if you still observe unexpected
initial behavior.  I haven't seen anything happening myself that I couldn't
eventually put down to recentering.

-- john, KE5FX



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Re: [time-nuts] Lady Heather question serial error

[John Miles]

Hmm.  No, I have no idea what would do that. :(  There's some sort of
handshaking incompatibility, it sounds like.  Try a fully-populated serial
cable, just to see if it makes a difference.

-- john, KE5FX

> -Original Message-
> From: time-nuts-boun...@febo.com [mailto:time-nuts-boun...@febo.com]on
> Behalf Of ESeacord
> Sent: Thursday, February 19, 2009 8:49 PM
> To: 'Discussion of precise time and frequency measurement'
> Subject: Re: [time-nuts] Lady Heather question serial error
>
>
> Hi all
> After finally getting the right serial cable, only uses tx-rx and ground.
> Everytime I start Lady Heather, I get the error message "serial receive
> error, code 0x2"
> The only other process running is outlook.
> The tbolt monitor program dspmon and tboltmon both appear to work
> properly.
> My system is 2.6ghz intel quad core with 4 gig of mem and plenty of hard
> drive space.
> Any ideas anyone??
> Thanks much
>
>
> Rix Seacord
> 22 Austin Rd
> Mahopac, NY 10541
> WA2TGF (Extra)
> Home 845-628-0892
> Cell 914-262-9186
>    
>
>


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Re: [time-nuts] Lady Heather command line modification question...

[John Miles]

Hmm.  Are you following the example shown in the readme file?  What is the
exact command line you're using where multiple options aren't working?

I normally use

"C:\Heather\heather.exe" /i=10 /mt=130

... myself.

-- john, KE5FX


> But, I have been unable to get more than one switch to work, the
> first in line..
>
> We need clarification on the exact syntax to use for multiple
> command line switches.
>
> Stan, W1LE
>


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Re: [time-nuts] Lady Heather command line modification question...

[John Miles]

Correct (although it only takes one  to exit if you're not in review
mode.)  I may add the ability to lock/unlock the keyboard in an upcoming
version, so that it'll ignore any accidental user input.

I agree that it would be cool if the initial graph contents could be
obtained by reading the log file, so that you could continue logging data
across execution sessions and scroll back as far as you want.  That'd be
Mark's call, though, as I only did the Windows conversion.

-- john, KE5FX

> -Original Message-
> From: Mike S [mailto:mi...@flatsurface.com]
> Sent: Wednesday, February 18, 2009 6:01 PM
> To: Discussion of precise time and frequency measurement
> Cc: John Miles
> Subject: Re: [time-nuts] Lady Heather command line modification
> question...
>
>
> John,
>
> I just started playing around with Lady Heather (for some reason, that
> sounds kinky :-) )
>
> Any chance of adding the ability to read from the log file when
> starting, so the graphs/stats can be recovered from a log? And
> optionally, continue collecting/adding data to that log, as might be
> desired if a stop/start is necessary.
>
> Also, it's not documented that  will quit the program. :-(
>
>


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Re: [time-nuts] Lady Heather command line modification question...

[John Miles]

The parameters need to be outside the quotes, or they're considered part of
the executable filename itself.  (When I posted the latest version the other
day, I added an example -- see http://www.ke5fx.com/heather/readme.htm and
click on the small image of the shortcut dialog.)

-- john, KE5FX


> The name 'C:Program Files\Heather\heather.exe /mp[=5]' specified
> in the Target box is not valid.  Make sure the path and
> file name are correct.
>
> What am I doing wrong?  Maybe I am not clear where to enter
> spaces?  I have tried different combinations, but no joy...
>
> Is this not the correct place to enter the /mp=5 suffix?
>


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Re: [time-nuts] Lady Heather display is GREAT!!!

[John Miles]

Hmm... in /vl mode there might be room for a large-format digital clock
display.  Not quite enough free space in the normal or /vs modes, I don't
think.

-- john, KE5FX

> -Original Message-
> From: time-nuts-boun...@febo.com [mailto:time-nuts-boun...@febo.com]on
> Behalf Of Michael Baker
> Sent: Monday, February 16, 2009 11:28 AM
> To: time-nuts@febo.com
> Subject: [time-nuts] Lady Heather display is GREAT!!!
>
>
> Hello, John and Mark--
>
> The display is beautiful and tells a great deal more
> from a quick glance than the Trimble factory supplied
> software. You guys did a great job with it!!
>
> The display looks really good when I do an ALT / ENTER
> to run the display full screen.  This display is the
> "cat's meow" and I will likely dedicate an old laptop
> I have sitting around to running it and leave it running
> full time on the shelf in my shop.
>
> Thanks again for all your work on this-- You and Mark have
> done all us T-Bolt users a great favor!!
>
> I am wondering about the big empty space on the lower
> left center of the display  Is this for some sort
> of future embellishment?   Hmm. How about a
> very large clock ticking away in that space or some other
> sort of running information?
>
> Mike Baker
> 
>
>
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Re: [time-nuts] DIY Frequency extension for HP Agilent

[John Miles]

>
> The NLB-300 and NBB-300 series MMICs from RFMD work very at up to 13GHz
> or so, certainly far better than a Mini-circuits ERA- whose gain will
> start to roll off at higher frequencies.  Designing a broadband gain
> stage to work up to 12GHz+ may not be as easy as it seems.  However it
> is made somewhat easier by the use of broadband chokes from the likes of
> Mini-Circuits, wideband inductors from Coilcraft and broadband
> capacitors from ATC - to name but three - there may be others as well.
>
> The 4-stage amplifier used by HP not only increases the signal level, it
> increases the slew rate (V/uSec) at lower frequencies.  It's not just
> about signal level, it's about getting fast edges.  The Hittite HMC363
> /8 is a great IC, using static flip-flops, and will work all the way
> down to DC - IF the edges are fast enough.  Ironically it may be the
> case that the lower frequency limit presents more of a challenge than
> the higher frequency limit.

True.  The Hittite parts can be used all the way down to DC, if the edges
are fast enough. :)

The last time I wanted to build a prescaler capable of DC operation, I ended
up using a tunnel diode to speed up the edges of low-frequency input
signals.  I used some crude LC filtering to bypass the TD for faster
signals, routing them directly to the prescaler chip.  The circuit worked
well enough, but it was pretty twitchy.

-- john, KE5FX




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Re: [time-nuts] Initial release of Lady Heather for Windows

[John Miles]

> John -
>
> I did have to run it as Admin.  I tried a few things on a Guest logon
> including a
> USB serial port but got the 0x02 error.  Just clicking on the
> Lady Heather
> icon
> worked on the first try using a real serial port..
>

So if you have a real serial port you don't need to run as admin, but if you
have a USB adapter you do, correct?

> Your display is beautiful - you did good.

Thanks!  The display's all Mark's doing.

-- john




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Re: [time-nuts] Initial release of Lady Heather for Windows

[John Miles]

Thanks for the confirmation -- I don't believe anyone else has tried it on
Windows 7 before.  Did you have to run it as admin?

Christopher, I imagine there's either a WoW64 compatibility problem or (more
likely) the unit you're using isn't 100% compatible with Trimble's TSIP
implementation for the Thunderbolt.  It would be interesting to hear if you
can try 64-bit Vista with a real Thunderbolt; otherwise there are too many
variables at play to make an educated guess as to what's going on in your
case.  Error code 0x02 means that it found the serial port and opened it
correctly, but timed out trying to perform a read operation.

-- john, KE5FX

> -Original Message-
> From: time-nuts-boun...@febo.com [mailto:time-nuts-boun...@febo.com]on
> Behalf Of Doug Hutton
> Sent: Wednesday, February 11, 2009 2:08 PM
> To: Discussion of precise time and frequency measurement
> Subject: Re: [time-nuts] Initial release of Lady Heather for Windows
>
>
> I just downloaded and ran it on Windows 7 and it works fine on
> a group-buy Thunderbolt..
>
> Doug Hutton
>
>
> --
> From: "christopher hoover" 
> Sent: Wednesday, February 11, 2009 12:14 PM
> To: 
> Subject: Re: [time-nuts] Initial release of Lady Heather for Windows
> (JohnMiles)
>

> > Is it known to run on Vista?   How 'bout Vista x64?
> >
> > I'm trying on Vista x64 with a GPSTM (related but not actually
> > thunderbolt),
> > I get:
> >
> > Serial receive error, code 0x2.
> >


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[time-nuts] Initial release of Lady Heather for Windows

[John Miles]

Mark and I have unified the Lady Heather code base between the DOS and
Windows versions, fixed various bugs and UI issues, and added some useful
features.  This is my "version 1.0" release:

http://www.ke5fx.com/heather/readme.htm

The app is a decent graphical replacement for tboltmon.exe at this point,
IMHO.  If you currently run tboltmon on your Thunderbolt, give this release
a try.

As before, if your Windows desktop is smaller than 1280x1024, you will need
to add /vs to your shortcut, or use /f to run in fullscreen mode.

-- john, KE5FX



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Re: [time-nuts] Lady Heather's Window

[John Miles]

> I think a more flexible fashion of setting size would be a good thing.
> The preferred fasion is always being able to do standard resize by
> dragging the edge, but saying x*y size at command line kind of works.

Yep, the code could support arbitrary x*y sizes, but he has several groups
of related parameters that are tied to the discrete size options -- and
also, I can only go into fullscreen mode in standard VGA/EVGA resolutions.
So I probably won't put a lot of work into that.  Left as an exercise to the
reader, as it were.  If I hack Mark's code too extensively, it'll be hard to
catch back up when he posts new updates.

> Avoiding the shrinking should be the main thing to do then, in this case
> it hurts more than it helps.

Yes, that's true in all cases, really.  It just confuses people.  When I
first wrote this code, there were some severe performance penalties
associated with odd scale factors on many systems, so halving the window
size in the event where the desktop area wasn't big enough to accommodate
its client area seemed like a good idea.

I also didn't want users running with a downsampled window without intending
to, since that's like running an LCD at a resolution other than its native
one, only worse.  The half-size window is a pretty good clue that things are
configured suboptimally.

I'll probably just "fix" the problem with a readme file, since there aren't
any easy hacks that work well in all cases where the desktop resolution is
too small for the window.  Forcing fullscreen mode in those cases would also
be an option.

> Oh... The oscillator ADEV positions at 2000 s and 5000 s is displaced
> over the 500s and 1000s respectively, 2 digits too much to the left and
> halfway up on the mentioned values, seems like 16 left and 16 up if the
> font is 8 x 8 as you say.

Not sure I follow you there; is this happening in a specific resolution?
The table seems to look OK in the default res (attached) - is this similar
to what you're seeing?

-- john, KE5FX
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Re: [time-nuts] Lady Heather Question

[John Miles]

I use the normal Win32 device-communications API (via CreateFile/ReadFile).
Same serial-interface module that I wrote to talk to Prologix GPIB-USB
dongles.It should support any COM port number you give it.

The graph ends up looking a lot neater with 10-second updates than with
1-second updates -- I wonder if that should be the default.  The PPS and ref
traces in particular seem to break up a lot at 1-second timescales.

-- john, KE5FX

> -Original Message-
> From: time-nuts-boun...@febo.com [mailto:time-nuts-boun...@febo.com]on
> Behalf Of Magnus Danielson
> Sent: Sunday, February 01, 2009 4:18 PM
> To: Discussion of precise time and frequency measurement
> Subject: Re: [time-nuts] Lady Heather Question
>
>
> John Miles skrev:
> > The DOS version had a bug that caused it to ignore the /2 altogether (it
> > hardwired the COM port back to 1 after parsing the command-line args).
> > That's fixed in the Windows build.
>
> Do you use Windows serial line routines or maintain Marks more direct
> access? For a Windows port the OS serial line routines should be the
> right thing. We should avoid having to force the configuration like I
> had to do initially.
>
> Cheers,
> Magnus
>
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Re: [time-nuts] Lady Heather Question

[John Miles]

The DOS version had a bug that caused it to ignore the /2 altogether (it
hardwired the COM port back to 1 after parsing the command-line arts).
That's fixed in the Windows build.

Mark: the Windows source code should still be able to compile for DOS at
your end, if you change the #define back.  If you'll switch to my copy (and
switch to .cpp compilation) it would be easy to keep them in sync.

-- john, KE5FX

> -Original Message-
> From: time-nuts-boun...@febo.com [mailto:time-nuts-boun...@febo.com]on
> Behalf Of Magnus Danielson
> Sent: Sunday, February 01, 2009 2:31 PM
> To: Richard W. Solomon; Discussion of precise time and frequency
> measurement
> Subject: Re: [time-nuts] Lady Heather Question
>
>
> Richard W. Solomon skrev:
> > Having failed to get the program working properly on an old 486 Laptop,
> > I installed it on a more modern machine running XP. When I try to open
> > the program I get an error message about Com Port Not Available ??
> >
> > How does one select the COM Port ?
>
> /2 should get it to run on COM2... however... due to my previous
> experience check your Hardware Driver settings and FORCE your com-port
> to COM1. That worked for me... but maybe the new Windows-port
> works better.
>
> Cheers,
> Magnus
>
>


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Re: [time-nuts] Lady Heather's Window

[John Miles]

Ah, I should have mentioned that.  You need to run it on a desktop that's at
least one 'standard size' larger than the window, or my graphics library
will halve the size of the window, which renders the text unreadable.

The text is still pretty cramped when running normally, but it's not a
standard Windows font -- it's a hardwired 8x8 raster font that's part of an
ancient platform-independent graphics library I wrote back when the Win95
Chicago beta came out.  So unfortunately there are no real options for
improvement there without rewriting a bunch of code to use actual Windows
fonts.

One thing that would help is running it in fullscreen mode, which I forgot
to enable.  Grab the newest build at http://www.ke5fx.com/tbolt/setup.exe
and add an -f option to your Windows shortcut if you want it to start in
fullscreen mode (or just use alt-Enter or the maximize button to toggle
fullscreen mode after running.)  Especially if you use it with /vs, the font
will appear much larger than it does in a window.

-- john, KE5FX

> -Original Message-
> From: time-nuts-boun...@febo.com [mailto:time-nuts-boun...@febo.com]on
> Behalf Of Magnus Danielson
> Sent: Sunday, February 01, 2009 11:03 AM
> To: Discussion of precise time and frequency measurement
> Subject: Re: [time-nuts] Lady Heather's Window
>
>
> Stijn,
>
> S. Nestra skrev:
> > I had the same problem of the ultra small text under XP. One of you
> > already tried to enlarge the window with /vl. I have found that the
> > opposite of this works: /vs. So if you use "heather /vs" you
> get the big
> > letters!
> >
> > Works for me,
>
> YES!!! It works for me too! I get a larger window too!
>
> Obviously there is something wrong with that part of the code, maybe
> Windows just scales the window size down to fit the screen.
>
> Great... now it is useful to me! :D
>
> Cheers,
> Magnus
>
> > Stijn PE1RKS
> >
> > John Miles schreef:
> >> Here's my quick-and-dirty Windows port (including the modified
> source code):
> >>
> >> http://www.ke5fx.com/tbolt/setup.exe (600K)
> >>
> >> Tested on XP, should be fine on Win9x/2K, no telling with Vista.
> >>
> >> As with Mark's original program, the default is COM1; you'll
> need to modify
> >> your Windows shortcut to run "heather /x" (without the quotes)
> for COMx.
> >>
> >> -- john, KE5FX
> >>
> >>
> >>> -Original Message-
> >>> From: time-nuts-boun...@febo.com [mailto:time-nuts-boun...@febo.com]on
> >>> Behalf Of Magnus Danielson
> >>> Sent: Saturday, January 31, 2009 10:31 AM
> >>> To: Richard W. Solomon; Discussion of precise time and frequency
> >>> measurement
> >>> Subject: Re: [time-nuts] Lady Heather Update
> >>>
> >>>
> >>> Richard W. Solomon skrev:
> >>>> I tried it on my Compaq 486 running WIN98SE I get a black screen
> >>>> with Logoff on it and a couple of other lines that make no sense ?
> >>>>
> >>>> Who has the Rosetta Stone ??
> >>> I do not know... British Museum maybe?
> >>>
> >>> I tried to recompile in my Cygwin environment but with no luck, failed
> >>> to compile.
> >>>
> >>> It seems to be beyond me... I know nothing about Windows... I
> just need
> >>> to run the damn thing for some apps...
> >>>
> >>> Cheers,
> >>> Magnus
> >>>
> >>>
> >>
> >> ___
> >> 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's Window

[John Miles]

By the way, I can't run the DOS version here at all, so let me know if
anything looks significantly different.

-- john, KE5FX

> -Original Message-
> From: John Miles [mailto:jmi...@pop.net]
> Sent: Sunday, February 01, 2009 4:50 AM
> To: Discussion of precise time and frequency measurement
> Subject: Lady Heather's Window
>
>
> Here's my quick-and-dirty Windows port (including the modified
> source code):
>
> http://www.ke5fx.com/tbolt/setup.exe (600K)
>
> Tested on XP, should be fine on Win9x/2K, no telling with Vista.
>
> As with Mark's original program, the default is COM1; you'll need
> to modify your Windows shortcut to run "heather /x" (without the
> quotes) for COMx.
>
> -- john, KE5FX
>
>
> > -Original Message-
> > From: time-nuts-boun...@febo.com [mailto:time-nuts-boun...@febo.com]on
> > Behalf Of Magnus Danielson
> > Sent: Saturday, January 31, 2009 10:31 AM
> > To: Richard W. Solomon; Discussion of precise time and frequency
> > measurement
> > Subject: Re: [time-nuts] Lady Heather Update
> >
> >
> > Richard W. Solomon skrev:
> > > I tried it on my Compaq 486 running WIN98SE I get a black screen
> > > with Logoff on it and a couple of other lines that make no sense ?
> > >
> > > Who has the Rosetta Stone ??
> >
> > I do not know... British Museum maybe?
> >
> > I tried to recompile in my Cygwin environment but with no luck, failed
> > to compile.
> >
> > It seems to be beyond me... I know nothing about Windows... I just need
> > to run the damn thing for some apps...
> >
> > Cheers,
> > Magnus
> >
> >


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[time-nuts] Lady Heather's Window

[John Miles]

Here's my quick-and-dirty Windows port (including the modified source code):

http://www.ke5fx.com/tbolt/setup.exe (600K)

Tested on XP, should be fine on Win9x/2K, no telling with Vista.

As with Mark's original program, the default is COM1; you'll need to modify
your Windows shortcut to run "heather /x" (without the quotes) for COMx.

-- john, KE5FX


> -Original Message-
> From: time-nuts-boun...@febo.com [mailto:time-nuts-boun...@febo.com]on
> Behalf Of Magnus Danielson
> Sent: Saturday, January 31, 2009 10:31 AM
> To: Richard W. Solomon; Discussion of precise time and frequency
> measurement
> Subject: Re: [time-nuts] Lady Heather Update
>
>
> Richard W. Solomon skrev:
> > I tried it on my Compaq 486 running WIN98SE I get a black screen
> > with Logoff on it and a couple of other lines that make no sense ?
> >
> > Who has the Rosetta Stone ??
>
> I do not know... British Museum maybe?
>
> I tried to recompile in my Cygwin environment but with no luck, failed
> to compile.
>
> It seems to be beyond me... I know nothing about Windows... I just need
> to run the damn thing for some apps...
>
> Cheers,
> Magnus
>
>


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Re: [time-nuts] Lady Heather Update

[John Miles]

I'm trying to bring the Win32 version up to date with the graphical version,
but am dealing with a bug that apparently puts the Thunderbolt into some
kind of mode where it returns junk data over the serial line.  My Win32
build runs for a minute or so, draws some graphs that don't make sense, and
then I have to go into TBoltMon.exe and do a warm reset to make it resume
sending normal serial updates.

Is this basically what the DOS version normally looks like (attached),
obvious errors aside?

-- john, KE5FX



> -Original Message-
> From: time-nuts-boun...@febo.com [mailto:time-nuts-boun...@febo.com]on
> Behalf Of Magnus Danielson
> Sent: Saturday, January 31, 2009 4:18 PM
> To: Discussion of precise time and frequency measurement
> Subject: Re: [time-nuts] Lady Heather Update
>
>
> Mark Sims skrev:
> > Hello again Magnus,
>
> Hi Mark,
>
> > If the program is started up and it is not seeing the Tbolt on the COM
> > port you should see the "Log: OFF" indicator,  two lines of text that
> > are the plot area header,  and the plot axes/grid.  Pressing  the
> > SPACE bar should bring up a help screen in place of the plot grid.
> > If all that is working, the problem is probably in the COM port.
> > It wants the tbolt to be at factory com settings (9600,N,8,1)
>
> That was not the problem. It failed with a big windows thing saying it
> would not find the COM1 and then the programmed died.
>
> > The program talks to the COM port UART directly.  It probably won't
> > work with a USB converter.  The default is COM1,  the /2 command line
> > option should select COM2 (but I don't have a machine here with two
> > serial ports to test it...  the com port code was lifted from another
> > program that did work with COM2).
>
> The trouble here was that COM1 was "felt" by the OS to be used for
> something else. Very strange. I had to force COM2 to become COM1 to
> solve it. /2 did not help as it actually was COM1 in hardware.
>
> > There are several command line options.  use /? to see them.
>
> I found them by tossing random commands at it... fairly quickly.
>
> My remaining problem is to get it to run in graphical mode.
>
> Cheers,
> Magnus
>
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Re: [time-nuts] Wenzel Oscillator Repair

[John Miles]

> The problem with the oscillator turned out to be even easier to fix than
> I could have hoped for.  There's a ferrite transformer on the output -
> possibly a balun.  The wire is about the thickness of a hair.  The
> ferrite isn't tied down - it's just held by the leads.  I don't know if
> it took a physical hit or if the solder just dissolved the wire over the
> years, but one of the leads had broken.  I resoldered it and instead of
> a wobbly level of -20 to -30 dbm into 50 ohms, I now have a much more
> satisfying level of ~ +12 dbm.  And the levels in the rest of the unit
> now make sense.  Instead of hitting a Minicircuit RPD-1 Phase Detector
> with a level around -30 dbm, it's now seeing a level of +7 dbm - just
> what it should be.
>
> I'd like to thank you, John,  and everyone else  for their ideas.  They
> were a great help.

You're welcome; that's exactly what was wrong with my ULN, actually.  The
output balun had a broken lead.  They should be gluing those down, I guess.
Someone had also broken the trimmer by shoving an alignment tool in too far,
but that wasn't the main problem.

-- john, KE5FX


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Re: [time-nuts] Wenzel Oscillator Repair

[John Miles]

You probably have a lot more room to play with, given the larger housing on
your OCXO.  The ULN series is rather densely packaged, and that was one
reason why I wasn't crazy about going after it with a propane torch.  In
your case I'd be tempted to try the torch method before actually damaging
the housing with a Dremel tool.

While fixing a couple of Ovenaire OCXOs that use a similar form factor, I've
noticed that their PC board edges don't come anywhere near the endcap.  The
Ovenaire parts were sealed with epoxy, so a heat gun was all that was needed
to open them, but I'm sure I could've opened them with a torch without
hurting anything, if they'd been soldered shut.

-- john, KE5FX

> -Original Message-
> From: time-nuts-boun...@febo.com [mailto:time-nuts-boun...@febo.com]on
> Behalf Of Ed Palmer
> Sent: Tuesday, January 20, 2009 5:59 AM
> To: time-nuts@febo.com
> Subject: Re: [time-nuts] Wenzel Oscillator Repair
>
>
> Now I understand!  I was planning to reuse the case.  It didn't occur to
> me to sacrifice the case and put the oscillator in another box.
>
> Thanks for the idea, John.
>
> Ed
>
> > Message: 3
> > Date: Mon, 19 Jan 2009 21:20:54 -0800
> > From: "John Miles" 
> > Subject: Re: [time-nuts] Wenzel Oscillator Repair
> > To: "Discussion of precise time and frequency measurement"
> > 
> > Message-ID: 
> > Content-Type: text/plain; charset="us-ascii"
> >
> > I used a fiberglass-reinforced cutoff wheel.  This can open practically
> > anything, but it puts a lot of vibration and dust into the innards of
> > whatever you're taking apart.  My guess was that this was safer
> than using a
> > torch.
> >
> > Since I wasn't going to be able to maintain the original hermeticity, I
> > remounted the oscillator in a Hammond box, like so:
> >
> > http://www.thegleam.com/ke5fx/w1.jpg
> >
> > I brought the trimmer (which was also damaged in this
> particular oscillator)
> > and oven-status LED out to the box lid, along with the four original
> > terminals.  Makes a nice package that can be easily opened for
> maintenance:
> >
> > http://www.thegleam.com/ke5fx/w2.jpg
> >
> > The repackaged OCXO seems to work fine.  I haven't made any hardcore
> > measurements with it but I can tell just by watching the
> counter that its
> > short-term stability is similar to my other unmolested 5 MHz ULN.
> >
> > -- john, KE5FX
> >
> >> -Original Message-
> >> From: time-nuts-boun...@febo.com [mailto:time-nuts-boun...@febo.com]on
> >> Behalf Of Ed Palmer
> >> Sent: Monday, January 19, 2009 4:07 PM
> >> To: time-nuts@febo.com
> >> Subject: Re: [time-nuts] Wenzel Oscillator Repair
> >>
> >>
> >> I hadn't thought of using a Dremel.  Did you use an abrasive wheel or a
> >> steel cutter?  The case on mine looks to be about 20 ga. tin-plated
> >> steel (~0.04" thick).  The gap is so small it might have been
> a friction
> >> fit to start with.
> >>
> >> Ed
> >>
> >>> From: "John Miles" 
> >>> Subject: Re: [time-nuts] Wenzel Oscillator Repair
> >>> To: "Discussion of precise time and frequency measurement"
> >>>   
> >>> Message-ID: 
> >>> Content-Type: text/plain; charset="us-ascii"
> >>>
> >>> I had a similar problem with a 5 MHz OCXO from their ULN
> >>>
> >> series.  There was
> >>
> >>> a bad solder joint on the output connection, easy enough to fix
> >>>
> >> once I got
> >>
> >>> the unit open.
> >>>
> >>> In my case I used a Dremel tool to cut the seam.  Suggest
> wearing a dust
> >>> mask, obviously, and keep your cuts close to the perimeter of
> >>>
> >> the can, in
> >>
> >>> case the PC board comes right up to the edge like mine did.
> >>>
> >>> -- john, KE5FX
> >>>
> >> ___
> >> 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] Agilent 53132A Needs Help

[John Miles]

I'd be inclined to take the error message at face value; you have some
corruption in EPROM or flash memory that isn't in an area that gets used
during the measurements you're making.  Contacting an Agilent rep would make
sense, as the 53132A is new enough that there might be an easy way to
upgrade/reflash the firmware.

-- john, KE5FX

>
> One of my 53132As, an Agilent unit, s/n KR01202209 fail the power-on self
> test with a FAIL:ROM error message. During the test the front
> panel display
> looks quite odd compared with the other counters. If I ignore the
> error and
> press Recall (my settings are in Recall 1) I can proceed to what
> seems like
> normal operation and the time intervals I have been collecting
> for years on
> this counter seem OK.
>
>
>
> I opened it up and there is not much there. While I suppose I
> could perform
> some simple tests like checking power supply outputs, I just
> wondered if any
> of you have had a similar experience or if you knew of a
> reasonable place to
> have it repaired. I can only imagine what Agilent would charge for this.
>
>


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Re: [time-nuts] Wenzel Oscillator Repair

[John Miles]

I used a fiberglass-reinforced cutoff wheel.  This can open practically
anything, but it puts a lot of vibration and dust into the innards of
whatever you're taking apart.  My guess was that this was safer than using a
torch.

Since I wasn't going to be able to maintain the original hermeticity, I
remounted the oscillator in a Hammond box, like so:

http://www.thegleam.com/ke5fx/w1.jpg

I brought the trimmer (which was also damaged in this particular oscillator)
and oven-status LED out to the box lid, along with the four original
terminals.  Makes a nice package that can be easily opened for maintenance:

http://www.thegleam.com/ke5fx/w2.jpg

The repackaged OCXO seems to work fine.  I haven't made any hardcore
measurements with it but I can tell just by watching the counter that its
short-term stability is similar to my other unmolested 5 MHz ULN.

-- john, KE5FX


> -Original Message-
> From: time-nuts-boun...@febo.com [mailto:time-nuts-boun...@febo.com]on
> Behalf Of Ed Palmer
> Sent: Monday, January 19, 2009 4:07 PM
> To: time-nuts@febo.com
> Subject: Re: [time-nuts] Wenzel Oscillator Repair
>
>
> I hadn't thought of using a Dremel.  Did you use an abrasive wheel or a
> steel cutter?  The case on mine looks to be about 20 ga. tin-plated
> steel (~0.04" thick).  The gap is so small it might have been a friction
> fit to start with.
>
> Ed
> > From: "John Miles" 
> > Subject: Re: [time-nuts] Wenzel Oscillator Repair
> > To: "Discussion of precise time and frequency measurement"
> > 
> > Message-ID: 
> > Content-Type: text/plain; charset="us-ascii"
> >
> > I had a similar problem with a 5 MHz OCXO from their ULN
> series.  There was
> > a bad solder joint on the output connection, easy enough to fix
> once I got
> > the unit open.
> >
> > In my case I used a Dremel tool to cut the seam.  Suggest wearing a dust
> > mask, obviously, and keep your cuts close to the perimeter of
> the can, in
> > case the PC board comes right up to the edge like mine did.
> >
> > -- john, KE5FX
>
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Re: [time-nuts] Wenzel Oscillator Repair

[John Miles]

I had a similar problem with a 5 MHz OCXO from their ULN series.  There was
a bad solder joint on the output connection, easy enough to fix once I got
the unit open.

In my case I used a Dremel tool to cut the seam.  Suggest wearing a dust
mask, obviously, and keep your cuts close to the perimeter of the can, in
case the PC board comes right up to the edge like mine did.

-- john, KE5FX

> -Original Message-
> From: time-nuts-boun...@febo.com [mailto:time-nuts-boun...@febo.com]on
> Behalf Of Ed Palmer
> Sent: Monday, January 19, 2009 2:05 PM
> To: time-nuts@febo.com
> Subject: [time-nuts] Wenzel Oscillator Repair
>
>
> Hello,
>
> I have a piece of equipment with a Wenzel 5 MHz oscillator from the
> Timekeeper  line.
> It's functioning (that is, it's on frequency), but the output level is
> 20 - 30 db lower than it should be.  The level seems to change every
> time I turn it on.  By the way, this unit does NOT have an option to
> disable the output.  I saw that was listed in one of the Timekeeper
> documents that I found.
>
> It seems a shame to junk it when the repair is probably easy.  The
> challenge is how to get into the thing in the first place.  Does anyone
> have any hints & tips on how to open or repair one of these soldered-can
> oscillators?  I found a page
>  that described
> opening an HP 10811 from a Z3801A, but more ideas are always welcome.
>
> Thanks,
> Ed
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Re: [time-nuts] ADEV test setup [was GPSDO TC & Damping]

[John Miles]

I'd like to see a similar test conducted against a local Cs clock (and/or
maser), just to get everything on one graph.

-- john, KE5FX

> -Original Message-
> From: time-nuts-boun...@febo.com [mailto:time-nuts-boun...@febo.com]on
> Behalf Of Bruce Griffiths
> Sent: Friday, January 09, 2009 1:26 PM
> To: Tom Van Baak; Discussion of precise time and frequency measurement
> Subject: Re: [time-nuts] ADEV test setup [was GPSDO TC & Damping]
>
>
> Tom Van Baak wrote:
> >> 4) The real stumbling block is obtaining a suitable reference.
> >> An FTS1200 or an OSA8607 may be suitable, however these are either rare
> >> or expensive.
> >> Some rubidium standards are also suitable.
> >>
> >
> > Bruce,
> >
> > Note that my Tbolt time constant plots were made using just a
> > 58503B GPSDO as the reference; not something more exotic.
> >
> > /tvb
> >
> >
> Tom
>
> Doesnt that introduce some correlations for larger tau as both the
> Thunderbolt and the 58503B are both locked to GPS?
>
> Bruce
>
>


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[time-nuts] Enrico Rubiola's new book

[John Miles]

Phase Noise and Frequency Stability in Oscillators:
http://www.amazon.com/gp/product/0521886775/

The UPS driver handed it to me 30 seconds ago, and I can already give it a
favorable review after opening it to a random page.  Exercise 6.2 on page
191: "Hack as many microwave oscillators as you can."

This book -- which I can immediately tell isn't long, dry, or
unreasonably-expensive -- seems like an effective marriage of math and
pragmatics, likely because it's based on the author's JPL tutorials and
industry lectures.  Looking through it, I'm seeing a lot of PN graphs which
are annotated with explanations of corner frequencies, slopes, and
comparisons with other sources, which are (IMHO) a great way to understand
what to expect from your own measurements.

Anyway: the book looks very approachable, relevant, and well-grounded in
hardware and processes often discussed on the list.  I'm looking forward to
spending some more time with it.

-- john, KE5FX


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Re: [time-nuts] DMTD mixer question

[John Miles]

Even though the ISE/Webpack toolchain is considered somewhat buggier and
less-capable than the competing Altera freeware, I prefer it because the
Altera package requires product activation.  Call it paranoia on my part,
but I see a lot of HPSDR experimenters who are going to be unhappy campers
when (not if) Altera decides to stop supporting their toolchain.

-- john, KE5FX


> Thanks for the info.  I saw the development system for $149 and
> thought the exposure would be worth the price if the exposure lasted
> more than 60 days.  Webpack sounds as if it will do the job.
>
>
> On Fri, 26 Dec 2008 23:38:02 -0800, Hal Murray
>  wrote:
>
> >Webpack is good enough to get a lot of work done.  You might
> want some of the
> >fancier features.  You probably don't want to pay for ISE if all you are
> >doing is hobby stuff.
>
> -- kc0ukk at msosborn dot com
>


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[time-nuts] FS: HP 8663A, near mint

[John Miles]

I've got a very clean late-production HP 8663A signal generator up for sale,
in case anyone is looking.  This description page will be posted to eBay
next week unless sold offline first:

http://www.ke5fx.com/8663a.htm

Will be packaged safely for shipment in a wooden crate.  Asking $3000, US
sales only.  Not the cheapest one on the market, but unlike typical
8662A/8663As sold on eBay, you will be happy when you get it.

Local pickup also OK (Seattle area).  Thanks!

-- john, KE5FX


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Re: [time-nuts] Agilent 53148A, thunderbolt and my 10 Ghz LO

[John Miles]

Well, sure, it's more accurate than the undisciplined OCXO in the counter,
that's the idea behind the Thunderbolt. :)

-- john, KE5FX

> -Original Message-
> From: time-nuts-boun...@febo.com [mailto:time-nuts-boun...@febo.com]on
> Behalf Of n3...@aol.com
> Sent: Friday, December 19, 2008 12:07 PM
> To: time-nuts@febo.com
> Subject: [time-nuts] Agilent 53148A, thunderbolt and my 10 Ghz LO
>
>
> I'm borrowing a power meter and frequency county from work, an
> Agilent 53148A. While it's slow at work I wanted to make some
> measurements and align my ham radio stuff.
>
> It's last calibration was in May 08. I let it warm up for several
> hours, and it has the oven option.
>
> My 10 Ghz LO is 10,224 Mhz and it was 70 hz off. Not a big deal
> for my application.
>
> I found the manual and figured out how to choose an external
> reference on the 53148. I just wanted to ask the group if the
> Thunderbolt would be more accurate than the internal reference? I
> want to think it is but my link to the thunderbolt spec sheet is
> no longer valid.
>
> This weekend I'll measure it again using the tBolt as a reference.
> ___
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Re: [time-nuts] Close-in phase noise question...more info...

[John Miles]

> Maybe I'm missing the decimal point.  What's the bandwidth of a crystal
> filter relative to the spectrum out of the same crystal used as an osc?
>

The oscillator's noise floor itself is superb, near -180 dBc/Hz beyond 1
kHz.  That is only true until you do something with it.  The idea behind the
crystal filters is to get rid of the broadband noise introduced by the
buffers and multipliers.

You don't put the crystal directly in series with the oscillator, but rather
after various multiplier stages.  See the HP note "Generation of low phase
noise microwave signals" at
http://www.ke5fx.com/Scherer_Low_PN_Signal_Generation.pdf , especially page
23.

The additional filtering won't necessarily solve Brian's problem of
minimizing phase noise at circa 1 KHz from a 630 GHz carrier, though.  That
is beyond anything I have tinkered with.

-- john, KE5FX


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Re: [time-nuts] Close-in phase noise question...more info...

[John Miles]

> More info on the LO chain:
>
> 1) 5MHz Wenzel OCXO <--Custom Osc for me.
> 2) MSA-1105 buffer MMIC and lumped LPF
> 3) 5MHz to 10MHz 1N5711 diode based doubler
> 4) MSA-1105 buffer and lumped LPF
> 5) 10MHz to 20MHz 1N5711 diode based doubler
> 6) 20MHz BPF

What kind of BPF?  A really narrow crystal filter would be nice here.  (You
have basically reproduced the 8568A/B's 20 MHz reference section.)

> 7) 20MHz drives sampling detector inside surplus Frequency
> West PLL block to lock 1320MHz cavity oscillator.

Sounds OK as long as the sampler loop's noise floor doesn't limit you.  I
haven't measured the in-band residual floor of any bricks but I'd be
surprised if an SRD multiplier wouldn't be quieter.

> 8) 1320MHz drives Frequency West SRD multiplier to 6.6GHz.

If I wanted to get to several GHz with what's in my junk box right now, I
would do what you did to get to 20 MHz, BPF it with a multipole crystal
filter, and then use a few more multiplier stages to get somewhere between
100 MHz and 1 GHz, a la the 8662A reference section, depending on the choice
of the next stage.

That VHF drive signal would go into either an HP 33002A or 33004A SRD
multiplier, or one of the Picosecond NLTL multipliers (e.g.,
http://www.picosecond.com/product/product.asp?prod_id=109 ) I picked up in
their fire sale when they shut down their fab.

> 9) 6.6GHz to 39.6GHz Milliwave diode multiplier/amp/filter
> 10) 39.6GHz to 79.2GHz in varactor doubler
> 11) 79.2GHz to 158.4GHz in varactor doubler
> 12) 158.4GHz into x4 sub-harmonic mixer

AFAIK the rest of the chain is fine.  I'd focus on getting rid of the brick
PLL, or at least taking pains to make sure that it's not the problem, before
worrying about the MMICs in your early stages.

Remember that there's no point in optimizing the PN of any one stage much
below the input-referred residual noise of the following stage.  MMICs, in
saturation or not, are pretty quiet.  Quieter than sampler loops anyway.

-- john, KE5FX


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Re: [time-nuts] Close-in phase noise question...

[John Miles]

The painful part is probably the first few stages, if you are starting at 5
MHz.  You probably want to do some HP 8662A-like tricks using crystal
filters to shave off the broadband noise below 1 GHz, and maybe SAW filters
above that.  This will do nothing for noise within 1 kHz, though... do you
really need a clean signal that close to the carrier all the way up to 630
GHz?

The noise characteristics of the MMICs seems to depend a lot on the fab
technology.  I can't seem to find my .PDF copy of it right now, but I have
one paper on microwave regenerative dividers where the authors measured the
residual PN of several contemporary parts driven to saturation.  At 4.5 GHz,
the 10 dB/decade corner frequency wasn't reached until past 100 kHz for the
Stanford Microdevices SGA-4186, which didn't speak well for the PN
performance of SiGe HBT parts.  They showed -143 dBc/Hz at 1 kHz for that
one.

The GaAs HBT part (Mini-Circuits ERA-5SM) they tested was among the best
(-156 dBc/Hz at 1 kHz).  Second-worst was an InGaP/GaAs HBT part (Stanford
NGA-489) at about -153 dBc/Hz at 1 kHz.  Still much better than the SiGe
part.

My understanding is that the newer GALI-series parts from Mini-Circuits are
InGaP HBT devices so they'd presumably perform about like the NGA-489.
You'd want to measure them to make sure, though, if your app is that
critical.

Take a look at NRAO's recent publications, especially those associated with
the ALMA array (many of which are on their site).  They're doing the real
bleeding-edge work at sub-mm these days.

-- john, KE5FX

> -Original Message-
> From: time-nuts-boun...@febo.com [mailto:time-nuts-boun...@febo.com]on
> Behalf Of wa1...@att.net
> Sent: Monday, December 15, 2008 8:54 AM
> To: time-nuts@febo.com
> Subject: [time-nuts] Close-in phase noise question...
>
>
> Looking for comment here...
>
> The background:
> I'm working on a sub mm-wave LO chain for
> a ham radio application. While chasing issues
> of close-in phase (ie: within 1KHz of RF
> carrier) by peeling the "layers of the onion",
> I'm starting to question the performance of
> the MMICs that are used as buffers and amps
> following my Wenzel reference OCXOs.
>
> Question(s):
> Should any MMIC be allowed to be driven
> close to compression or into compression
> when striving for best close-in noise?
>
> I know and have seen the NF of a MMIC
> degrade while in compression, but my
> target right now is close-in noise rather
> than broadband noise.
>
> My design, in summary, takes 5MHz up to 630GHz
> via several multipliers and PLL stages.
>
> -Brian
>

>


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Re: [time-nuts] Date codes on hp 5071a?

[John Miles]

The date code is not a production date, necessarily, but the date of that
particular design revision (presumably when it was released to
manufacturing).  It sets a lower bound, but your unit could potentially be
several years newer.  You can get a better idea by looking for the latest
date code on various ICs and capacitors.

-- john, KE5FX

> -Original Message-
> From: time-nuts-boun...@febo.com [mailto:time-nuts-boun...@febo.com]on
> Behalf Of Bruce Griffiths
> Sent: Thursday, December 11, 2008 8:33 PM
> To: Discussion of precise time and frequency measurement
> Subject: Re: [time-nuts] Date codes on hp 5071a?
>
>
> aceamuseme...@mchsi.com wrote:
> >
> >  Hi,I was wondering by chance if someone familiar with hp date
> coding could tell me the date of manuf. of this 5071a
> >
> > 3608A01190
> >
> > Thanks,
> > ___
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> > and follow the instructions there.
> >
> >
> Manufactured in USA during 8th week of 1996
>
> Bruce
>
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Re: [time-nuts] Sub Pico Second Phase logger

[John Miles]

> > > The Symmetricom 5120A does something very clever to alleviate this
> > > problem.  Explained in US patent 7,227,346 and "Direct-Digital
> Phase-Noise
> > > Measurement"; J. Grove, J. Hein, J. Retta, P. Schweiger, W. Solbrig,
> and
> > > S.R. Stein; 2004 IEEE International Ultrasonics, Ferroelectrics, and
> > > Frequency Control Joint 50th Anniversary Conference, pages 287-291.
> > >
> > > Joe
> > >
> > >
> > I've read the patent.
>
> The paper is also worthwhile, and available on the web somewhere (don't
> recall where, but google found the pdf).  I had to read the patent
> multiple times to figure out what's going on.  The correlation
> approach is
> old as the hills, and only the digital phase detector was patentable.

If you find a link to the Grove paper that's not behind an IEEE paywall,
please post it.  I'd like to read that one.

-- john, KE5FX



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Re: [time-nuts] Ball-Efratom FRK-L manual [SEC=UNCLASSIFIED]

[John Miles]

Hadley's site has this one: http://to-way.com/tf.html

-- john, KE5FX

> -Original Message-
> From: [EMAIL PROTECTED] [mailto:[EMAIL PROTECTED]
> Behalf Of Quigg, Stephen
> Sent: Monday, December 08, 2008 8:06 PM
> To: time-nuts@febo.com
> Subject: [time-nuts] Ball-Efratom FRK-L manual [SEC=UNCLASSIFIED]
> 
> 
>  
> 
> Looking for a manual for the FRK-L.
> 
> Thanks in advance
> 
>  
> 
> 

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Re: [time-nuts] thoughts on cesium tube failure modes

[John Miles]

Actually your earlier advice proved golden.  I believe I've been able to
verify that the tube is at least within throwing distance of its factory
spec (see test results at http://www.ke5fx.com/cs.htm including the
configuration details).

I haven't tried playing with the low-frequency test coil at all but it
doesn't appear that it'll be necessary to mess with it.  Much appreciate the
help.  Any objection to posting copies of your two emails on the web page?

-- john, KE5FX



> John,
>
> You can manually de-gas the ionizer and oven filaments.
>
> It looks like you had already brought the oven up to temp so just work on
> the ionizer.
>
> You can bring the voltage up slowly and keep watch on the ion pump
> current so it does not get too high.
>
> Once you have got it up to the rated voltage and the pump current is low
> you can bring up the oven.
>
> You do not need to provide the RF to test and see if the tube has a
> response.
>
> Once you have the oven and ionizer up and running and applied a DC
> C-field current,
>
> (I'd have to look up the current you need), the adjustable mass
> spectrometer voltage
>
> (the ionizer supply floats on this), and the -2000VDC EM voltage you can
> apply a 1/2 zeeman frequency
>
> signal to the flop coil and while adjusting the freq and voltage look for
> the peak. Once you see it
>
> adjust the mass spectrometer voltage (max +18VDC) for a peak.
>
> If you see the peaks during this portion you can then remove the 1/2
> zeeman frequency signal
>
> and start trying to input some RF.
>
> Good Luck!
>
> Corby


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Re: [time-nuts] My 5062C tale

[John Miles]

I went ahead and bought the 5062C service manual from Manuals Plus.  I'll
contact Dave at Artek Media next week sometime to see if he's interested in
scanning the whole thing...

-- john, KE5FX


> -Original Message-
> From: [EMAIL PROTECTED] [mailto:[EMAIL PROTECTED]
> Behalf Of Corby Dawson
> Sent: Monday, December 01, 2008 12:09 AM
> To: time-nuts@febo.com
> Cc: time-nuts@febo.com
> Subject: Re: [time-nuts] My 5062C tale
>
>
>
> Tim,
>
> I do have a schematic of the voltage multiplier block in the 5062C ion
> pump supply.  If I
>
> remember its 3 diodes and 3 caps. If you'd like I'll dig it up for you so
> you
>
> can repair your module.
>
> Corby Dawson
> 
> Click here for free information on how to reduce your debt by
> filing for bankruptcy.
> http://thirdpartyoffers.juno.com/TGL2141/fc/PnY6rw22U57D2SvzUwlK0G
> mNfZKFtn8PpvDpiOEFrvLD2czGP3dKJ/
>
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Re: [time-nuts] Thoughts on Cs tube failure modes

[John Miles]

Hmm!  I appreciate the tip.  I'll confess it didn't occur to me to try to
force more current through the ion pump.  The supply I was using was limited
to about 300 uA, but I took your advice and tried a beefier one, set to 3
kV.  As I increased the current limit from 0 towards 5 mA, the ion-pump
current fell back to ~25 uA once I reached 1000 uA.

At the rate I was adjusting the current-limit control on the Glassman
supply, this occured about 10 seconds after power-up.  It seems stable now
at 25 uA, several minutes later.

I didn't leave the hot-wire ionizer energized for more than 10-15 seconds,
all told.  I'll let the ion pump run for a few hours, and then try the
hot-wire ionizer again.  Should I bother with the other supplies (Cs oven
heater, EM, mass spec), or is it reasonable to recondition the tube using
only the ion pump and hot-wire ionizer terminals?

Keep in mind that I don't have a 5062C mainframe, just the Cs tube and some
bench supplies.  I'm essentially recreating Tom's experiment from
http://www.leapsecond.com/pages/cspeak/ but without benefit of an actual
clock mainframe.  So I don't have a filament shutdown/recycle controller in
the picture.  Obviously that would be needed if I were to actually build a
clock around the tube, but for now, I just want to see if the tube is
functional at all, and determine its figure of merit.

-- john, KE5FX



> John,
>
> What you describe with the ion pump curent is normal if the tube has been
> powerd off for a long time.
>
> Th mainframe normally would turn the oven and ionizer filaments off when
> the ion pump current pegged.
>
> After minutes (can be quite a few minutes) the ion pump current will drop
> as it pumps the surge of outgassing from the heated filaments.
>
> The cycle repeats and can take a couple days on a stubborn tube.
>
> You bypassed that circuit so I'm not sure how much gas you introduced.
>
> If after a couple days the current is still pegged try connecting an
> external high voltage supply of around +3000VDC that can provide at least
> 5ma. (turn unit off)
>
> Let it run overnight and if the current comes down reconnect the internal
> power supply and turn the mainframe back on.
>
> You probably will see it peg again and the see the oven shut down (it
> happens fast!), just leave it on and it should start cycling and
> eventually the filaments will reach the oven set points and have
> outgassed enough so that the protective circuit will not trip.
>
> Then you can try to see if the rest of the tube has any life. (you may
> have to reduce the oven set resistor to 130 ohms as well as reducing its
> companion overtemp resistor. This is the value the Navy uses to get the
> last bit of life out of the tube, don't do it if you can get the rated
> beam current at the original value!)
>
> If you email me I can give you my evening phone number if you need some
> more info.
>


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[time-nuts] Thoughts on Cs tube failure modes

[John Miles]

I recently found a tube from a 5062C on eBay in unknown condition for not
*too* much money, and thought it would be interesting to power it up on the
bench.  Once I got it and saw the 19xx-prefix serial number, I wasn't too
optimistic, since it could potentially be 25 years old or more.  Things went
well for the first few steps of the process, but then the experiment failed
big-time.

1) I first applied +2600V to the ion pump with nothing else connected.  Spec
is < 10 uA.  There was a brief spike to ~100 uA, but within a few seconds,
the current began to drop rapidly, ending up at about 1 uA after a few
minutes.  So far, so good.

2) I then brought the Cs oven up to temperature slowly with a variable
supply.  The 5062C runs its oven in a thermostatic loop, but it was easy
enough to warm the oven up slowly over 10 minutes or so, watching the
thermistor resistance to achieve the 200-ohm reading indicated on the tube
label.  The ion pump current rose to about 2.5 uA during the Cs oven warmup
process.

3) I then attempted to bring up the hot-wire ionizer, which takes 1 volt at
about 1.6 amps (when hot).  Simultaneously, the 22-mA C-field current and
13.9-volt mass-spec supply was applied.  As with the Cs oven, I brought the
ionizer voltage up slowly.

4) At that point the ion pump supply went into full current limiting at
circa 300 uA.

I killed the power quickly, removed the oven and hot-wire ionizer supplies,
and tried powering the ion pump up by itself once again.  Although a DMM
check indicated infinite resistance across the ion pump, the HV supply still
went into current limiting.

I'm guessing that the hot-wire ionizer element had enough crud on it to kill
the vacuum when it vaporized.  The tube envelope is probably OK, because the
ionizer wire itself didn't burn out.  Unfortunately I was watching only the
hot-wire ionizer current during that part of the process, so I don't know if
there was a point where I could have observed a rise in ion pump current and
backed off in time to avoid permanent damage.

The last step would have been to connect the -1900V electron multiplier
supply, feed in a 9.192632 GHz signal from an HP 8672A which would be
frequency-modulated with a slow sawtooth, and watch for an output signal on
a scope with a high-Z opamp buffer.  Unless there is some kind of sequencing
taboo that says "bring up the electron multiplier before the ionizer", I
don't immediately see what I might have done wrong.  Anyone see any obvious
newbie mistakes in the account above?  Or was it just a matter of expecting
too much from a Cs tube that might have been 20 years old?

For what it's worth, the electron multiplier also shorts out its (negative)
supply now.  I don't know if that would've happened earlier, since I never
tried to energize it during the pre-test checkout.

-- john, KE5FX


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Re: [time-nuts] Eclipses and atomic clocks

[John Miles]

> http://www.amendez.com/Noahs%20Ark...

I'm sure there's a more appropriate list for this bogosity.  

-- john, KE5FX


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Re: [time-nuts] EZGPIB error

[John Miles]

That's a Winsock HOST UNREACHABLE error.  If you're moving the Prologix
board from one subnet to another, are you reconfiguring its IP address?

-- john, KE5FX

> -Original Message-
> From: [EMAIL PROTECTED] [mailto:[EMAIL PROTECTED]
> Behalf Of Bruce Griffiths
> Sent: Sunday, November 23, 2008 12:18 PM
> To: Discussion of precise time and frequency measurement
> Subject: Re: [time-nuts] EZGPIB error
>
>
> Ian Sheffield wrote:
> > Hello chaps,
> >
> > A quick question to the assembled multitude rather than
> bothering Ulrich directly, as some of you must have seen this problem:
> >
> > What causes the error message Socket Error # 10065
> > No route to host, when using EZGPIB with my Prologix latest
> version interface with my laptops?
> >
> > EZGPIB works fine from my desktop PC but gives this error
> message with both of my laptops running XP (one XP Home, the
> other is XP Pro).
> >
> > The Prologix itself is working fine, as it controls and reads
> my HP5334 perfectly using the direct Prologix commands. EZGPIB ,
> as stated, also works fine from the Desktop PC.
> >
> > What is not configured correctly in the laptops?
> >
> > Many thanks in advance,
> >
> > Ian.
> Are you using the latest version of EZGPIB?
>
>


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Re: [time-nuts] To improve a Tbolt?

[John Miles]

> What power supply did the TAPR Thunderbolt use?

The green, orange, and red traces used the supply module that came with the
TAPR order.  You can see the characteristic hump around 3 kHz that appears
in many of Tom's plots with this supply as well.

The blue trace was the old-style packaged Thunderbolt with the integrated
switching supply.

> Have you considered using a variant of the Wenzel supply filters to
> cleanup the spurs in the 1-10kHz region.

It couldn't hurt.  However, I don't tend to take spurs below -120 dBc very
seriously, because they can come from so many different sources outside my
control.  The HP 3048A system components were scattered all over the room at
the time these graphs were taken, and I had a strong cellular/pager
transmitter on the building immediately next door.  In any event the 3048A's
own spur-level specification is about -115 dBc.

I try not to lose sleep over low-level spurs unless/until they interfere
with an actual application, then I look into the specific one(s) that are
causing trouble.  Sloppy, perhaps, but ars longa, vita brevis and all that
good stuff...

> This is trivial with the low current -12V supply but would require some
> design effort for the +12V and +5V supplies.
> Using a more modern opamp (simplifies biasing) to augment the
> performance of such a filter for the higher current supplies would be
> worthwhile.
> Even dropping the spur level by 20dB is probably worthwhile.

I think the best way to deal with wideband noise and spurs is at the
architectural level.  Wall off the GPS clock and its supplies entirely, and
use its 10 MHz output to phase lock the clock you're actually using to drive
critical stuff.  That clock would be fed with a clean supply and tightly
integrated with its application, as opposed to mounted 20 feet away on
another rack.

With that philosophy, the GPS clock's performance at 10 Hz and below is
worth sweating out, but phase noise and spurs at wider offsets may not be.

-- john, KE5FX



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Re: [time-nuts] To improve a Tbolt?

[John Miles]

> On your rubidium comment, one needs to be a little careful about
> expectations. For short tau (say 0.1 to 10 seconds) your average
> cheap eBay surplus telecom Rb will have far less performance
> than a good OCXO. Yet mid-term (say 10 to 10^4 seconds), a
> Rb-GPSDO will win. However, long-term the LO makes much less
> difference since GPS always wins. And GPS aside, clearly the
> holdover performance of Rb will blow away OCXO.
>

Good point, there's a big piece of the curve where simply upgrading a
quartz-based GPS standard to drive an Rb would not be a win.  Two pieces,
actually, since Efratom (at least) doesn't seem to care much about phase
noise.

> So it all depends on ones need. I guess my main point is that a
> typical rubidium-based TBolt is not necessarily, just because it's
> "atomic", automatically better than a stock TBolt at every point.
>
> If you'd like to test an FRS or LPRO version of a TBolt for me let
> me know. I'd rather see your plots than my words.

I could graft a rubidium source onto the original Thunderbolt platform I
used for the OCXO tests, but I currently don't have a good way to look at
Allan deviation compared to the TSC/maser setup you've got.  I can measure
the phase noise easily enough but it'd be better to get it back to you for
longer-term tests, especially if the loop parameters need to be adjusted
iteratively.  That would be a heat-death-of-the-Universe process on a
3048A...

-- john, KE5FX


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Re: [time-nuts] To improve a Tbolt?

[John Miles]

I've upgraded the graph on the http://www.ke5fx.com/tbolt.htm page to show
the performance of my Thunderbolt from the TAPR group buy (in orange) next
to the traces for my older unit before and after the 10811 upgrade.

There is no upside to tinkering with the OCXO on the TAPR units, unless you
have something that can beat a 10811.  You could replace it with a rubidium
source and get better short-term stability, but I don't think swapping one
quartz OCXO for another would be a useful thing to do.

-- john, KE5FX

> -Original Message-
> From: [EMAIL PROTECTED] [mailto:[EMAIL PROTECTED]
> Behalf Of Ulrich Bangert
> Sent: Friday, November 21, 2008 2:58 AM
> To: Time nuts
> Subject: Re: [time-nuts] To improve a Tbolt?
>
>
> I would be interested in this information as well!
>
> Best regards
> Ulrich Bangert
>
> > -Ursprungliche Nachricht-
> > Von: [EMAIL PROTECTED]
> > [mailto:[EMAIL PROTECTED] Im Auftrag von Dan Rae
> > Gesendet: Donnerstag, 20. November 2008 18:58
> > An: time-nuts@febo.com
> > Betreff: [time-nuts] To improve a Tbolt?
> >
> >
> > I have been reading with interest John Miles' page about his Tbolt
> > 'upgrade'.
> >
> http://www.thegleam.com/ke5fx/tbolt.htm
>
> I have a newly acquired Tbolt here, and also have lying around an almost
>
> identical 10811-60111 OCXO which I am considering using with it, exactly
>
> as John describes.  However my Tbolt is of a later vintage than John's
> (2005 date code) and I wonder if that would show as big an improvement
> as John reports.  The on board OCXO on this one has a Trimble sticker on
>
> it, but otherwise looks similar to the one pictured on John's page.  The
>
> GPS receiver area of my board also looks very different, but I don't
> think this would have any effect.
>
> Not having the sort of phase noise measuring facilities here to be able
> to test it, I am wondering if anyone else has done this with a similar
> vintage Tbolt, and could say if it is likely to show as big an
> improvement as John seems to be getting.
>
> I was a little surprised at the amount of short term variation, of the
> order of minutes duration, that I was seeing on another Tbolt when using
>
> it to set a Rb standard.
>
> The obvious answer to my question is to try it and see, but I'd
> appreciate hearing from anyone who has tried it!
>
> Dan
>
>


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