Re: [time-nuts] Traveling to the US west coast

[David Smith]

If Attilla is going to be in the Bay area I would like to come up and maybe 
have dinner. I live in Fresno, 180 miles south of San Francisco.

Dave W6TE

-Original Message-
From: time-nuts  On Behalf Of Pete Stephenson
Sent: Friday, May 18, 2018 8:29 PM
To: time-nuts@febo.com
Subject: Re: [time-nuts] Traveling to the US west coast

Interestingly enough, I've moved from. Switzerland (where I've met Atilla) and 
am now in the Bay Area. It's be great to meet up again. 

Even if Attila doesn't make it to the SF area, I'd be interested in getting 
some local time nuts together. 

Cheers! 
-Pete

On Fri, May 18, 2018, at 6:36 PM, Jerry Hancock wrote:
> Are you going to be in San Francisco area?  Maybe we could get a time- 
> nuts breakfast together with a couple of us.
> 
> Regards,
> 
> Jerry
> 
> 
> 
> > On May 17, 2018, at 11:25 PM, Attila Kinali  wrote:
> > 
> > Hi,
> > 
> > Some of you might already know, I will fly to the US west coast to 
> > attend IFCS. Afterwards, I will be in Seattle for a couple of days 
> > (from 25th to 31st). If you are in the area and want to meet up, 
> > please drop me an email (off-list).
> > 
> > 
> > Attila Kinali
> > --
> > It is upon moral qualities that a society is ultimately founded. All 
> > the prosperity and technological sophistication in the world is of 
> > no use without that foundation.
> > -- Miss Matheson, The Diamond Age, Neil Stephenson 
> > ___
> > time-nuts mailing list -- time-nuts@febo.com To unsubscribe, go to 
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> > AmbvPimzxeevqo%3D=0
> > and follow the instructions there.
> 
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> and follow the instructions there.


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

[David Smith]

If you have a low cost VPN account, you just need to connect to a server 
located in the US. Then you can watch it from where ever.

Dave W6TE

-Original Message-
From: time-nuts [mailto:time-nuts-boun...@febo.com] On Behalf Of Heinz Breuer
Sent: Wednesday, January 17, 2018 5:17 PM
To: Discussion of precise time and frequency measurement 
Subject: Re: [time-nuts] PBS, Tue evening, The Secret of Tuxedo Park

In Europe there is a good chance that the French/German cultural public TV 
Station "arte" will rebroadcast it via ASTRA satellite some day. arte shows a 
lot of PBS documentations.

vy 73 Heinz DH2FA, KM5VT

Von meinem iPhone gesendet

> Am 17.01.2018 um 23:07 schrieb Adrian Godwin :
> 
> Joe's link worked for me earlier this afternoon in the UK, but is 
> blocked now at 10pm local time.
> Glad I watched it when I could !
> 
> 
> On Wed, Jan 17, 2018 at 10:00 PM, Bill Metzenthen 
> wrote:
> 
>> It also worked in Australia last night.  I watched a few minutes and 
>> decided to watch the rest today.  Unfortunately, it is now 
>> geo-blocked :-( It's also blocked on the PBS site.
>> 
>> 
>> 
>>> On 18/01/18 02:09, Heinz Breuer wrote:
>>> 
>>> The link worked perfectly in Germany.
>>> 
>>> vy 73 Heinz DH2FA, KM5VT
>>> 
>>> Von meinem iPhone gesendet
>>> 
 Am 17.01.2018 um 15:48 schrieb EB4APL :
 
 Joe,
 Thank you for the pointer. The regular web site don't allow the 
 series to be viewed outside USA.
 
 73 de Ignacio, EB4APL
 
 
> El 17/01/2018 a las 2:47, Joseph Gray escribió:
> If you want to watch this episode online, go here:
> https://eur01.safelinks.protection.outlook.com/?url=http%3A%2F%2Fv
> ideo.unctv.org%2Fvideo%2F3008204310=02%7C01%7C%7C9ce35d569ce8
> 4cceb66b08d55e119ca7%7C84df9e7fe9f640afb435%7C1%7C0%7C
> 636518352086759489=CG1xCfztOS%2BdTuCo%2Bgd%2BQm%2BYffg%2FARL
> W%2BcN4sh2gRMw%3D=0
> 
> This is the UNC Public TV web site.
> 
> Joe Gray
> W5JG
> 
> 
> 
>> On Tue, Jan 16, 2018 at 2:28 PM, Bill Tracey  wrote:
>> 
>> To record OTA television I use an HDHomeRun :
>> https://eur01.safelinks.protection.outlook.com/?url=https%3A%2F%2
>> Fwww.silicondust.com%2Fhdhomerun%2F=02%7C01%7C%7C9ce35d569ce
>> 84cceb66b08d55e119ca7%7C84df9e7fe9f640afb435%7C1%7C0%
>> 7C636518352086759489=A93GBtLd7vrNcz58i9QQdiIEnfPmIzg7wkNAtk
>> Dn5hc%3D=0
>> 
>> I'll grab tonight's run of The Secret of Tuxedo Park
>> 
>> Cheers,
>> 
>> Bill
>> 
>> At 09:04 AM 1/16/2018, you wrote:
>> 
>> I can't stress enough how important Loomis was to the history of
>>> precise
>>> timekeeping in early radio, telephone, pendulum clock, quartz 
>>> oscillator era. And for those of us who still have Loran-C 
>>> receivers can thank him (Loomis Radio Navigation -> LRN -> 
>>> Loran).
>>> .
>>> 
>>> If someone knows how to record any time/clock/navigation parts 
>>> of PBS show for non-US viewers let me know, off-list.
>>> 
>>> /tvb
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> 

Re: [time-nuts] HP Spec Analyzer FS

[David Smith]

I'm interested in it. I think I'm in driving distance from Fresno, CA.
Dave W6TE

-Original Message-
From: time-nuts [mailto:time-nuts-boun...@febo.com] On Behalf Of Perry Sandeen 
via time-nuts
Sent: Sunday, December 31, 2017 2:38 PM
To: time-nuts@febo.com
Subject: [time-nuts] HP Spec Analyzer FS

Hi,
I have a HP 8590A that I got from Bob Camp in a trade.  In the spring we will 
be moving so I'm shedding some of my large TN gear.
I works OK but it may need to be cal'd if one wants precise mearsurments.
$365 plus shipping from 92220  about 30 lbs.
Regards,
Perrier
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Re: [time-nuts] H-maser drift

[David Smith]

Yes,



Thank you John. Enjoyable reading and informative.



Dave W6TE



Sent from Mail for Windows 10




From: time-nuts  on behalf of John Ponsonby 

Sent: Tuesday, November 21, 2017 12:26:35 PM
To: time-nuts@febo.com
Subject: Re: [time-nuts] H-maser drift

There seem to be a lot of misunderstandings about H-masers. To set the record 
straight note:
1. The flow of hydrogen is generally controlled using a palladium membrane, 
though a palladium-silver alloy is to be preferred because it is less likely to 
crack. Only hydrogen will diffuse through the palladium-silver membrane, so as 
well as being a temperature controlled regulator it is also a filter. Indeed it 
is an isotopic filter through which even deuterium doesn’t pass. The protons 
are thought to migrate through the membrane and recombine on the output surface 
first into atoms and then into H2 molecules. I used thin walled 
palladium-silver tubes which had roughly the dimensions of a match stick. 
Hydrogen on the inside was at about twice atmospheric pressure with output into 
“vacuum” on the outside. Control is by heating with a large current flowing 
along the rather low resistance tube. Russian H-masers use nickel tubes rather 
than the more expensive palladium-silver. Such a “palladium leak” requires only 
a few seconds on Turn-On to settle to a steady flow.
2. Hydrogen from the "palladium leak” passes to a “dissociator" which is a 
small bulb made of heavily boronated glass, e.g. Pyrex, in which the H2 
molecules are dissociated into H atoms by a non-contacting RF discharge. Atomic 
hydrogen recombines very readily on any metal surface so the discharge is 
either by magnetic or electric field acting through the glass wall. Metals are 
charactersised by having conduction bands full of free electrons. Boron is an 
electron acceptor, so Pyrex is very unlike a metal and it has a low surface 
recombination rate. Not as low as FEP120 (See 5. below) but one can’t line a 
discharge bulb with it.
3. The very high Q RF cavity (loaded Q ≈ 36000), which is tuned very exactly to 
the hydrogen frequency of 1,420,405,751Hz, operates in the TE011 mode in which 
the oscillating RF magnetic field is toroidal, going up the middle and down the 
outer part of the cavity. The resonant frequency is much more sensitively 
dependent on the cavity diameter than on its length.
4. Inside the cavity is the "storage bulb" which is made not of glass but of 
fused quartz. It is typically about 1mm thick. Fused quartz is chosen for its 
exceptionally low RF loss tangent. But of course it has a dielectric constant 
which results in its loading the cavity which is thus a little smaller than one 
first thinks. Since it is very difficult to manufacture quartz bulbs to normal 
engineering tolerances it is not possible to calculate how much the cavity will 
be loaded. So it is not unusual to manufacture the cavity to match the given 
storage bulb.
5. The inside of the storage bulb is coated typically with a layer of FEP120, a 
Dupont product akin to Teflon. An H atom can make of the order of 10,000 
bounces off its surface without change of quantum state. Also H atoms won’t 
stick to the coating. (Non-stick frying pans are coated with FEP120 and what is 
true for an egg is true for an atom.)
6. The shape of the storage bulb should be chosen to maximize the “filling 
factor”. This is defined as: η’=Vb^2b/Vcc  Here the numerator is the 
product of the storage bulb volume Vb times the square of the mean of the z 
component of the RF magnetic field Hz averaged over the internal volume of the 
bulb b, and the denominator is the product of the cavity volume Vc times the 
mean of the square of the magnitude of the RF magnetic field Ha averaged over 
the entire volume of the cavity c. A spherical bulb is non-optimal though may 
early masers had spherical storage bulbs.
7. The RF discharge generates UV. This shines up the beam path and illuminates 
the bulb coating in the region where the incoming atoms first make contact with 
the bulb coating. This UV undoubtledly damages the FEP120 coating. The 
deterioration of the coating may be one of the causes of long term drift.
Cheers
John P

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Re: [time-nuts] HP8640

[David Smith]

Hello Ulrich,

I have an 8640 I was going to put up for sale in the next few weeks. It’s in 
almost perfect condition. All of the gears are intact with no cracks or 
splitting. I think this SG may have been in a lab environment most of it’s 
lifetime.

Contact me off list if you are interested.

Dave W6TE
w...@msn.com

Sent from Mail for Windows 10

From: KA2WEU--- via time-nuts
Sent: Tuesday, June 6, 2017 6:06 PM
To: time-nuts@febo.com
Subject: Re: [time-nuts] HP8640

Hi , I am trying to find an well working  HP 8640 to do some  measurements
like SSB  FM and AM noise.

Who can help ?  73 de Ulrich N1UL
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[time-nuts] HP 5061A Cesium Beam Std

[David Smith]

Hello Time Nuts Friends,

I have acquired an HP 5061A off of EBAY and I believe the cesium beam tube may 
be bad. The ion pump meter pins out and never comes down to a reasonable level. 
I don’t have an external HVPS to check the tube as suggested in the manual. I’m 
thinking the worst here… that the tube is probably bad. The seller listed it 
“For Parts” and the usual “I have no way of checking it.” Fortunately, he has a 
14 day return policy. He’s offered me $400 to keep it. I have $725 in it.

My question to the group is… are there replacement tubes available? Any 
suggestions on what to do with it if I can’t get a replacement tube?

Thanks in advance,

Dave Smith / W6TE
Sent from Mail for Windows 10

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Re: [time-nuts] Abstract for consideration at 2016 New Mexico TechFest

[David Smith]

Hi Cash,
My interest in time and frequency measurement goes way back when I was just out 
of high school and was employed by a few local radio stations. We were charged 
with ensuring the station frequency was within the FCC limits. I remember 
receiving the report from our external frequency referance "expert" every 
month. "Northwest Frequency Monitoring" (or something like that). He flew 
around the Western US in his Piper Aztec taking frequency measurements for 
radio and TV stations. This was 1965 or so. I would then compare his readings 
with my own HP-117A, VLF Frequency Comparator at 60 KHz.
A few years later there was an article published in 73, magazine (I think) that 
described using the 3.58 MHz color burst frequency from local TV stations (when 
they had a network feed) which one could use to phase lock oscillators etc. A 
Rubidium standard was out of the question at that time. 
Then along came Brook Shera's neat little GPS frequency standard. That's about 
the time the telecom industry was removing from service the HP Z3801A GPSDO's. 
I bought several of them at $285 each and thought that was a bargain.  I still 
have one that distributes a 10 MHz signal throughout my lab with an HP 5087A 
Distribution Amp configured for 5 and 10 MHz output.
A few years later I became interested in EME (earth-moon-earth) operation as 
well as roving on the microwave bands. I was fortunate to operate (in 2009) the 
Stanford University's 145 foot dish operated and maintained by SRI. We operated 
1296 MHz and used a Rb for phase locking the radio although that really wasn't 
necessary at that frequency and mode. It wasn't very long ago that the market 
was flooded with 10 MHz Rb's that could be had for $60 or less. I think that 
market has dried up now.
I operate on the microwave bands up through 24 GHz. Without phase locking the 
transverter's onto a very good standard, it's very difficult to make contacts 
on the upper bands (10 and 24 GHz). I use G3RUH's fine GPS DO for generating 
the 10 MHz reference as well as a Jackson Labs GPSDO.  

Dave - W6TEARRL Technical CoordinatorAMSAT Area Coordinator

> From: m...@alignedsolutions.com
> Date: Tue, 29 Dec 2015 12:45:32 -0800
> To: time-nuts@febo.com
> Subject: Re: [time-nuts] Abstract for consideration at 2016 New Mexico
> TechFest
> 
> Hi Cash.   
> 
> Here is a bit of a narrative and some comments from an amateur radio 
> perspective.
> 
> I got into the time nuts hobby as off shoot from amateur radio.   I was using 
> a pc sound card to evaluate the frequency stability of some of my ham radios 
> by looking at the change in "beat note" when receiving wwv in SSB mode.
> 
> I realized that I couldn't use wwv as a frequency standard due to Doppler 
> shift and in practice my radios with tcxo's were stable enough that it wasn't 
> clear if I was seeing Doppler shift from wwv or the radios drifting.   
> 
> After some research I purchased a gpsdo from James Miller G3RUH which 
> provided a suitable frequency source to replace wwv for my purposes.   Later 
> I wanted to see accurate that GPSDO was.  To make a long story short
> 
> Ended up buying half a dozen HP5370 and HP5335 time interval counters a 
> Jackson labs fury GPSDO, two Z3805 GPSDO's, a thunderbolt, a BVA, a FTS1050, 
> an HP105, two time source 2700's (with prs 10 rb's) various stand alone rb's, 
> ocxo's, various HP5328 counters with 10811 ocxo's, an NTP server etc.
> 
> Wrote  some scripts using Ulrich's plotter software to log the data to text 
> files and processed the data using John's time lab software (thanks !).  
> 
> Couldn't quite convince my self to buy a cesium standard and a time pod 
> (figured I would end up wanting to get two or three of each once I started 
> down that road.)
> 
> I was (and am) more than satisfied with the performance of the G3RUH GPSDO 
> for my amateur radio activities.
> 
> At the time work involved long periods of travel so collecting data for a few 
> weeks at a time then looking at it later worked out ok.  Later I also had 
> little time or interest for Amateur radio due to travel.
> 
> After a few years I decided to get back into amateur radio.   I still use the 
> G3RUH gpsdo to check the frequency of my VHF and up gear.   It works well for 
> this as it produces useable harmonics to over 1.3 GHz and it runs from a 13.8 
> volt power source.  From time to time I still compare the G3RUH GPSDO to my 
> other references.   
> 
> I have found for VHF and up weak signal work it is very helpful to have a 
> suitable frequency standard.   
> 
> Regarding frequency calibration of my radios.  In practice listening to 
> harmonics from the G3RUH GPSDO with the radio set to SSB mode and looking at 
> the resulting audio frequency works well for me.  So far I've resisted the 
> temptation to modify my radios to accept an external frequency reference, but 
> checking their accuracy prior to use is part of my setup routine.   I suspect 
> at some point I'll 

Re: [time-nuts] New GPSDO on EBAY From China

[David Smith]

Thanks for the discussion on this GPSDO. 
I researched the archives on this going back a few months but didn't find 
anything. 
Although I consider myself a newby or novice Time-Nut I do have three other 
GPSDO's I've had a Z3801 running for more than 10 years. 
My interest in the unit in question lies in the need for a light weight unit I 
can use as a stable accurate source for my 24 GHz transverter that I use for my 
rover and contesting efforts. I need something light weight as well as accurate 
and stable with low phase noise and needs to be able to be located on or close 
to a portable tripod. I did order one of James Millers units to fulfill these 
needs. I just thought this may be a much less expensive alternative.
Thanks again for the discussion. 
Happy New Year to all! 

Dave - W6TE From: kb...@n1k.org
 Date: Tue, 30 Dec 2014 09:33:06 -0500
 To: time-nuts@febo.com
 Subject: Re: [time-nuts] New GPSDO on EBAY From China
 
 Hi
 
  On Dec 29, 2014, at 8:51 PM, Li Ang lll...@gmail.com wrote:
  
  Hi
  One of my friend had one. Here is the test result from him.
  
  
 
 Ok, that data is actually more encouraging than the data on the selling site. 
 He ran it long enough to get past the hump in the ADEV curve at 4,000 
 seconds. The blue trace shows that the test setup *can* resolve the data 
 properly. 
 
 So now the question becomes - what is going on with the filter software in 
 the BG7TBL unit? It’s obviously done differently than the HP filter software. 
 There are a number of people (not me) on the list that have expressed 
 interest in digging into GPSDO firmware.
 
 Bob
 
  
  Bob Camp kb...@n1k.org于2014年12月29日星期一写道：
  Hi
  
  Ok, well that’s a move forward on this GPSDO. There is a *lot* more data
  on that listing than there was a month ago.
  
  Thanks for digging it up  and posting the link.
  
  If you look at the ADEV at 1 second, it’s running at 2.67 x10^-11. That’s
  all coming from the Erratum Rb that they are using as a reference. At 100
  seconds the Rb should be around 2.67 x10^-12 and the MV-89 should be about
   2x10^-11. They combine as the square root, so that would be 3.3 ppt or
  less. The unit is running at 4.8 ppt so the filter is having some impact at
  that point.
  
  Out around 5,000 seconds the unit has a major hump. The Nortel GPSTM has
  a similar hump, but much closer in. It’s performance at 5K seconds is much
  better. The Lucent KS boxes beat this part across the entire range. That
  makes some assumptions, since there is no good ADEV data inside 100 seconds
  on the plot.
  
  The final question about the plot would be - what happens at longer tau?
  The run was stopped before it really got past the peak in the filter. It
  would be nice to see some data that at least gets back down to  1 ppt at
  the longer tau’s. Without that data it’s unclear how well the whole system
  is doing. That’s not to say it’s not doing well. It could be doing a great
  job, there’s just no way to know from the data.
  
  
  
  My guess is that this is very much like your counter project, just a bit
  further along. They have a nice looking unit, but are still trying to
  figure out the bugs and finish up the software …
  
  Bob
  
  On Dec 28, 2014, at 6:19 PM, Li Ang lll...@gmail.com wrote:
  
  Hi
   This unit is done by BG7TBL. In his store on taobao.com, there is a
  adev
  chart. Please refrer to this link
  
  http://item.taobao.com/item.htm?spm=a1z10.3.w4002-1278071728.49.XHJlQLid=42336500072
  
  
  
  
  2014-12-29 1:56 GMT+08:00 Dan Rae dan...@verizon.net:
  
  On 12/28/2014 7:25 AM, David Smith wrote:
  
  Hello Friends,
  I found this new inexpensive GPSDO on ebay listed from a seller from
  China:
  
  Dave, these have been discussed in the past at some length on this list.
  I would point out that they use a re-cycled Morion OCXO.  I have had
  two of
  these ovens from China; one worked fine, the other has a very high
  level of
  spurious outputs.  I would be wary of using these in anything without
  first
  testing them thoroughly.
  
  Dan
  
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[time-nuts] New GPSDO on EBAY From China

[David Smith]

Hello Friends,
I found this new inexpensive GPSDO on ebay listed from a seller from China: 
http://www.ebay.com/itm/GPS-DISCPLINED-CLOCK-GPSDO-10M-OUTPUT-SQUARE-WAVE-/111514491254?pt=LH_DefaultDomain_0hash=item19f6c81976
It looks interesting and tempting BUT the seller doesn't give any spec's on 
the unit or osc type. The seller has 10 negative and 18 neutral feedback's in 
the past 6 months out of a total of 2110 for a feedback score of 99.6%; many 
for poor communication.
Does anyone on the list have any experience with this GPSDO? Any advice on 
buying one?
Best regards and Happy New Year!

Dave - W6TE   
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[time-nuts] Rockwell/Conexant Jupiter(?) 10kHz Output Off Frequency

[David Smith]

The Jupiter (TU-30) board in my homebrew GPSDO has died.

A friend gave me some unmarked Jupiter-like boards with Conexant chips 
that he had been told were Jupiter compatible.
The boards are mounted on an aluminium plate that has a puck-type 
antenna on it.  One of the chips has a sticker with ZOD8 V1.83 printed 
on it.


The boards have the same connections as a Jupiter, and I've been able to 
connect one to my GPSDO in place of the dead Jupiter.
It eventually starts outputting sensible messages with location etc. and 
the homemade display on the GPSDO shows that everything is supposedly 
normal.


However, the PLL will not lock.  Even though there's 10 kHz from the 
board (which I can only measure to 1 Hz accuracy), the PLL keeps hunting 
for lock.
The 10kHz is in sync with the 1pps also from the board.  However, when I 
compare the 10kHz to 10 MHz from another GPSDO, it doesn't appear synced 
to GPS - it must only be fractions of a Hz off, though.


At the moment, I'm thinking there are 3 possibilities:
- I need to send a command to the board to configure the 10kHz/1pps 
somehow.  The Jupiter doco doesn't show any command like that and seems 
to assume the 10kHz and 1pps are always there.
- There are components for the 10kHz/1pps syncing missing.  I've already 
had to add a jumper wire where bits for supplying active antenna power 
were missing (from factory).
- The firmware doesn't support 1pps / 10kHz.  Perhaps the boards were 
meant for navigation only.


Does anyone recognise these boards and have experience with extracting 
10kHz from them?


Regards,
David Smith

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Re: [time-nuts] Subject: HP Agilent VLF Comparator Receiver 117A Frequency

[David Smith]

That's my HP 117A receiver that I listed. It's $120 and I pay for shipping. 
It's the last of three I had. Shipping will cost between $20 -$25 depending on 
where you live. I could either offer it for sale or send it to the landfill. I 
chose to offer it to someone who might want to own a piece of history.
And yes I have the antenna as well.
73,

Dave - W6TE

**
  
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Re: [time-nuts] Maintaining boatanchors (was Capacitor Failures)

[David Smith]

Where is k4obb's website?

Dave W6TE
  - Original Message - 
  From: paul swedmailto:paulsw...@gmail.com 
  To: Discussion of precise time and frequency 
measurementmailto:time-nuts@febo.com 
  Sent: Friday, October 22, 2010 7:00 PM
  Subject: Re: [time-nuts] Maintaining boatanchors (was Capacitor Failures)


  I save images at k4obbs website.
  I will have to look at bluefeather see what thats about.
  Thanks

  On Fri, Oct 22, 2010 at 7:02 PM, Chuck Harris 
cfhar...@erols.commailto:cfhar...@erols.com wrote:

   I don't believe the parts are failing due to structural
   problems, but rather are just leaking down their buried charge.
  
   It should be quite possible to refresh them by erasing them and
   reprogramming.
  
   -Chuck Harris
  
  
   Bob Camp wrote:
  
   Hi
  
   Find pin compatible replacement EPROM's while you still can. They don't
   make all those small / slow / multiple supply
   / parts any more.  Saves building all sorts of strange adapter boards as
   well as re-shooting the memories.
  
   Bob
  
  
   On Oct 22, 2010, at 6:44 PM, Poul-Henning Kamp wrote:
  
In message
   
1498648302.205602.1287785250803.javamail.r...@sz0110a.emeryville.camailto:1498648302.205602.1287785250803.javamail.r...@sz0110a.emeryville.ca
 .
   mail.comcast.net,
   k6...@comcast.netmailto:k6...@comcast.net writes:
  
What to do? Pop out the parts and rewrite them? Dump them to disk as
   well?
  
  
   Make backup-copies while they have no problems.
  
   -- Poul-Henning Kamp   | UNIX since Zilog Zeus 3.20 
p...@freebsd.orgmailto:p...@freebsd.org| TCP/IP since RFC 956 FreeBSD
   committer   | BSD since 4.3-tahoe Never attribute to malice what can
   adequately be explained by incompetence.
  
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Re: [time-nuts] watch innards video

[David Smith]

Norm, the link was stripped out of your message. Please send it to me directly.
 
Thanks,
 
Dave W6TE
 
 Date: Wed, 8 Sep 2010 10:32:52 -0400
 From: normn3...@stny.rr.com
 To: time-nuts@febo.com
 Subject: [time-nuts] watch innards video
 
 Hi all!!
 If you don't know a mainspring from an escapement, watch this video. 
 I was wondering about the physics of the hairspring, jewel pin and 
 escapement/pallete arm. 
 Cool stuff.
 Norm n3ykf
 
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Re: [time-nuts] Slightly OT - GPS-Based Accurate Direction Finding

[David Smith]

Thanks for all the interesting responses.

Some background - I'm needing an accuracy of 1 degree or better.  The 
experiments are using digital communication modes and sometimes aircraft 
scatter so signals are regularly inaudible and often non-existent, so 
peaking by ear is not usually an option.


I've paced out direction using a handheld GPS (GPSMap 60CSX) and this 
gives reasonable results if there's a reasonable baseline.  It's a bit 
impractical when operating from a firetower though!


Using Sun/Moon/Stars is difficult when there's cloud. We've tried using 
Sun RF Noise, but accuracy declines significantly when the sun is high 
in the sky.


VOR is an interesting suggestion, but a very sharp (and large) antenna 
would be needed and multi-pathing may cause problems.


So, my interest turns back to a GPS-based solution and the military 
units suggested by Brooke look perfect ... except that they are most 
likely a restricted export and unavailable to us Down Under.


Other links on Brooke's site have lead me to many papers researching 
GPS-based attitude systems.  I note that the Uni of Calgary have 
developed a package called HEADRT+ that can take raw measurements from 
several GPS mounted on a small baseline and produce attitude 
information.  This is the sort of thing I'm after, but I get the 
impression that licensing costs are high.


As Atilla says, the software is probably not that fundamentally 
complicated.  However, the devil is possibly in the detail of aligning 
sample timing, positioning ...


Any other suggestions?

Regards,
Dave

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[time-nuts] Slightly OT - GPS-Based Accurate Direction Finding

[David Smith]

As a fair percentage of the discussion amongst the learned gentlemen on 
this group involves GPS-based timing systems, I'd like to ask a non-time 
related, but GPS-related question.


As part of microwave radio experimentation, often on windy hilltops, I 
have a need to find direction very accurately.  I have seen advertised 
GPS-based Azimuth Pointing Systems such as this:

http://www.ascscientific.com/APS.html
However they are a little (lot) out of my budget range.

The system seems to work by taking the raw satellite phase information 
from two separate GPS systems and crunching the data to come up with an 
azimuth figure.  Has anyone heard of a (Open Source?) program that could 
be used to do these calculations?


Regards,
David Smith

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Re: [time-nuts] FRS-C TTL / sine outboard filter question

[David Smith]

Leigh, I have the same FRS-C TTL unit. I do not have a manual.

Would you be so kind as to send the conversation info to me?

Thanks,

Dave W6TE
  - Original Message - 
  From: Leigh L. Klotz, Jr WA5ZNUmailto:le...@wa5znu.org 
  To: time nutsmailto:time-nuts@febo.com 
  Sent: Tuesday, June 22, 2010 9:54 PM
  Subject: [time-nuts] FRS-C TTL / sine outboard filter question


  At the local flea market, I picked up what appears to be an Efratom 
  FRS-C.  It is marked TTL internally.  It has the passive connector 
  board, but not the active board with the 15 MHz synthesizer on it.

  Mine is marked TTL internally.  The service manual has a chart showing 
  the differences between the sine and TTL options, and I converted it to 
  the sine version by changing a jumper to a resistor and populating an LC 
  filter with 10uH and 100pF (~5 MHz).  I also terminated the RF 
  connection on the connector board with a 47 ohm resistor to ground.

  The output now doesn't have the tremendous overshoot it used to have, 
  but it's also not very sinusoidal.  That's not surprising given the 
  simplicity of the on-board filter.

  Instead of a multi-stage LC filter, I wondered about a crystal ladder 
  filter: since the output frequency is fixed, the high Q and low cost of 
  the crystal filter might be an advantage, but I wasn't sure about how 
  effective xtal ladder filters are at suppressing harmonics, as each 
  individual crystals would have odd overtone responses, so it might not 
  be a good plan.

  Does anyone have practical experience with a filter topology for 
  cleaning up the output of the FRS-C at 10 MHz?

  Leigh.

  P.S. Just so that I can be topical, note that the FRS-C has a C-field 
  adjustment 0-5V input, so I could use it as the reference oscillator for 
  a TPLL.


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Re: [time-nuts] 10 MHz Distribution Amplifier

[David Smith]

Hi Chuck,

Great to see you here. I just joined this GREAT group a few days ago,

You may not remember me. I'm Dave W6TE ex WA6YDI. You were one of my first 
contacts on 2M EME back in the early 80's. You were up in the Bay area and I 
was in Fresno. I'll never forget the contact because (you were one of my first 
and) I was hearing you on two paths; the terrestrial path as well as 2.5 
seconds later the EME path. I think that was the year that Michael Owen and 
group activated the big Ontario dish VE3ONT. 

I hope things are well with you and your wife. Please take care and stay in 
touch

73,

Dave W6TE 
w...@msn.commailto:w...@msn.com
  - Original Message - 
  From: Chuck Smallhousemailto:w...@theriver.com 
  To: time-nuts@febo.commailto:time-nuts@febo.com 
  Sent: Friday, November 13, 2009 1:03 AM
  Subject: [time-nuts] 10 MHz Distribution Amplifier


  Down East Microwave Inc now has a four channel 10 MHz distribution 
  amplifier with some gain and  LP filters on each output.

  Their price with the PC board and all components, but without 
  connectors and enclosure is about $25

  Chuck,  W7CS


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Re: [time-nuts] Rubidium standard

[David Smith]

Yes, that's the page .

Thanks, Dave
  - Original Message - 
  From: philmailto:fort...@bellsouth.net 
  To: Discussion of precise time and frequency 
measurementmailto:time-nuts@febo.com 
  Sent: Thursday, November 12, 2009 12:27 AM
  Subject: Re: [time-nuts] Rubidium standard



  - Original Message - 
  From: David Smith w...@msn.commailto:w...@msn.com
  To: Discussion of precise time and frequency measurement 
  time-nuts@febo.commailto:time-nuts@febo.com
  Sent: Thursday, November 12, 2009 2:31 AM
  Subject: Re: [time-nuts] Rubidium standard


  I'm new to the list. Having said that, I ran across a webpage from a chap in 
  Australia or maybe it was New Zealand. In any event he claims that the Rb 
  lamp can be brought back to life. He says that he has rejuvenated over 30 
  units with bad lamps and they work great after his process.

  I will try and dig up the webpage if anyone is interested.

  Dave / W6TE
- Original Message - 
From: Hal 
Murraymailto:hmur...@megapathdsl.netmailto:hmur...@megapathdsl.net
To: Discussion of precise time and frequency 
  measurementmailto:time-nuts@febo.commailto:time-nuts@febo.com
Sent: Wednesday, November 11, 2009 11:15 PM
Subject: Re: [time-nuts] Rubidium standard



 I was told by a Technical Support Engineer from Symmetricom Global
 Services that The typical life span is ~10 years for these Rubidium
 Time Bases.

 This is in response to my request for information on a Ball/Efratom
 PTB-100.

 Is this a typical life span of a rubidium standard?

It's lower than what I would expect.  The target market is the Telco and 
  Cell
Phone industry.  They expect (or at least used to) long lifetimes.

Maybe life span means how long they run it, planning to replace it with
newer gear long before it actually wears out.

I would have expected more like 20 years of useful life.  That's running 
  24x7
in a reasonable environment.  That's also with hacker reliability, aka 
  it's
not a disaster if it dies.  So if you get one that was dumped by a Telco
after 10 years, it's not crazy to run it 24x7 and expect many more years.
(Just as long as you don't go crazy if it doesn't last that long.  I can 
  buy
a lot of surplus stuff for the price of new gear as long as I'm willing to
tolerate the time gaps and effort of replacing it when it dies.)


The LPRO-101 blurb says:
  Amb.Temp: 20 °C 25 °C 30 °C 40 °C 50 °C 60 °C
  MTBF (hrs) 381k 351k 320k 253k 189k 134k

A year is 8760 hours (ignoring leap years).  Call that 10K.  So they 
  expect
25 years at 40C and 32 years at 30C.

That's calculated MTBF.  YMMV.


 Do some standards last longer than others?

I'm sure some are better than others.  I don't have any data.


 What are the symptoms of a failing rubidium bulb?

Externally?  It stops working.  The error signal (maybe a LED too) will go
on, or rather the locked signal (open collector?) will go off.

The frequency stability will fall off a cliff.


  He says that he has rejuvenated over 30 units with bad lamps and they work 
  great after his process. 
  Is this what you were referring to? Near the end he explains how to 
  rejuvenate lamps.
  
http://www.febo.com/pipermail/time-nuts/attachments/20081103/c205b683/attachment.pdfhttp://www.febo.com/pipermail/time-nuts/attachments/20081103/c205b683/attachment.pdf
 


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Re: [time-nuts] 10 MHz Distribution Amp

[David Smith]

Hi Dick,

Down East Microwave makes a 10 MHz distribution kit called the 10-4. I think it 
sell around $50. 1 input port and 4 output ports.

Dave W6TE
  - Original Message - 
  From: Richard W. Solomonmailto:w1...@earthlink.net 
  To: time-nuts@febo.commailto:time-nuts@febo.com 
  Sent: Thursday, November 12, 2009 10:20 AM
  Subject: [time-nuts] 10 MHz Distribution Amp


  A friend of mine is looking for an inexpensive way to distribute
  his 10 MHz T-Bolt signal to other instruments. The TAPR unit, while
  very nice, is a tad on the pricey side when you add in the enclosure.

  Any ideas what he could use that is not so expensive ?

  Thanks, Dick, W1KSZ

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Re: [time-nuts] Rubidium standard

[David Smith]

I'm new to the list. Having said that, I ran across a webpage from a chap in 
Australia or maybe it was New Zealand. In any event he claims that the Rb lamp 
can be brought back to life. He says that he has rejuvenated over 30 units with 
bad lamps and they work great after his process. 

I will try and dig up the webpage if anyone is interested.

Dave / W6TE
  - Original Message - 
  From: Hal Murraymailto:hmur...@megapathdsl.net 
  To: Discussion of precise time and frequency 
measurementmailto:time-nuts@febo.com 
  Sent: Wednesday, November 11, 2009 11:15 PM
  Subject: Re: [time-nuts] Rubidium standard



   I was told by a Technical Support Engineer from Symmetricom Global
   Services that The typical life span is ~10 years for these Rubidium
   Time Bases.

   This is in response to my request for information on a Ball/Efratom
   PTB-100.

   Is this a typical life span of a rubidium standard?

  It's lower than what I would expect.  The target market is the Telco and Cell 
  Phone industry.  They expect (or at least used to) long lifetimes.

  Maybe life span means how long they run it, planning to replace it with 
  newer gear long before it actually wears out.

  I would have expected more like 20 years of useful life.  That's running 24x7 
  in a reasonable environment.  That's also with hacker reliability, aka it's 
  not a disaster if it dies.  So if you get one that was dumped by a Telco 
  after 10 years, it's not crazy to run it 24x7 and expect many more years.  
  (Just as long as you don't go crazy if it doesn't last that long.  I can buy 
  a lot of surplus stuff for the price of new gear as long as I'm willing to 
  tolerate the time gaps and effort of replacing it when it dies.)


  The LPRO-101 blurb says:
Amb.Temp: 20 °C 25 °C 30 °C 40 °C 50 °C 60 °C
MTBF (hrs) 381k 351k 320k 253k 189k 134k

  A year is 8760 hours (ignoring leap years).  Call that 10K.  So they expect 
  25 years at 40C and 32 years at 30C.

  That's calculated MTBF.  YMMV.


   Do some standards last longer than others?

  I'm sure some are better than others.  I don't have any data.


   What are the symptoms of a failing rubidium bulb? 

  Externally?  It stops working.  The error signal (maybe a LED too) will go 
  on, or rather the locked signal (open collector?) will go off.

  The frequency stability will fall off a cliff.




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




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Re: [time-nuts] Calculating frequency differences using Lissajoufigures

[David Smith]

I'll drink to that!
Dave W6TE
  - Original Message - 
  From: J. L. Tranthammailto:jlt...@worldnet.att.net 
  To: 'Discussion of precise time and frequency 
measurement'mailto:time-nuts@febo.com 
  Sent: Saturday, November 07, 2009 3:45 PM
  Subject: Re: [time-nuts] Calculating frequency differences using 
Lissajoufigures


  And you watched it the whole time to see the 'reversal' of the rotation.  

  Once going, it is not possible to tell 'which way' it is rotating.  In other
  words, can you tell if it is rotating clockwise or counter clockwise?  

  I would suggest making the GPSDO the 'trigger' for the scope and watch the
  LPRO on one of the input channels of the scope.  If I recall correctly, if
  it moves left, the LPRO is high and if it moves right, it is low in
  frequency.  Please do not quote me on this as I have had a glass of wine.
  After all, it's 5 o'clock somewhere.

  Joe

  -Original Message-
  From: time-nuts-boun...@febo.commailto:time-nuts-boun...@febo.com 
[mailto:time-nuts-boun...@febo.com] On
  Behalf Of Hal Murray
  Sent: Saturday, November 07, 2009 3:50 PM
  To: Discussion of precise time and frequency measurement
  Subject: Re: [time-nuts] Calculating frequency differences using Lissajou
  figures


   So your frequency drift in this example is 1.7e-11 / month.

   Not quite, you need to take the sign of the frequency difference into 
   account.

   But the sign of the difference would be obvious from the rotation
   direction of the Lissajous.   

  Only if you remembered to include the direction when you took the first 
  measurement and if you connected the scope up the same way a month later.


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




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Re: [time-nuts] Thunderbolt and USB to RS232 converters

[David Smith]

 
 In the device manager, choose View: Show hidden devices. The grayed
 out devices have once been, but are no longer, connected to your
 machine. Remove the ones that you no longer care about. You can also
 remap the comport-numbers in the properties of the serial port devices,
 use the button Advanced... there.
 
 I'm aware of those, but the next new USB serial device you plug in will
 still be the next higher number.  It is the counter for this number I've
 not been able to locate.


I've just sorted this problem on another thing I was doing, although I 
was only up to COM14!

It seems there are hidden hidden devices.  Have a look at this:
http://support.microsoft.com/kb/315539

So once you clean out the hidden devices and the hidden, hidden devices, 
then you can remap your USB Com port back to COM3 or whatever, and it'll 
stay there!

Note that even plugging the same USB-RS232 converter into another USB 
port on a hub will create a new COM port.

Regards,
Dave
VK3HZ


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[time-nuts] Jupiter GPS Settings For Best Timing Performance

[David Smith]

I've been working on the performance of my portable GPSDO (very similar 
to G3RUH design) and have got down to a reasonable level.  Testing 
against an HP3815A, it will remain within better than 1x10^-10 for 
periods of 10-15 mins.

However, there are times when it seems to get a hit and it will then 
move up to ± 5x10^-10 before settling down again.  The movement seems to 
follow the time constant of the PLL loop filter, possibly indicating 
that it's coming from the Jupiter GPS?

Reading the Jupiter doco (Zodiac GPS Receiver Family Designer's Guide), 
there seem to be several Zodiac Binary messages that can be used to 
alter the GPS's performance (e.g. Satellite Elevation Mask Control).  I 
already have a processor talking to the GPS card and displaying 
position, time, gridsquare, status etc.  It would be a simple matter to 
have it tweak the parameters as required.

Does anyone have any experience with this?

Regards,
David Smith

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Re: [time-nuts] Trak 8426-1 manual

[David Smith]

); SAEximRunCond expanded to false
Errors-To: [EMAIL PROTECTED] RETRY

Not sure if this helps, but I had an 8821A, bought with no manual.  I 
emailed Trak and they were happy to provide the appropriate User Manual 
as a PDF, once I'd identified the unit.  If you want the contact details 
for the Trak person, please contact me off-list.

The 8821A manual may provide some useful info (e.g. Command set):
http://home.exetel.com.au/dwsmith/trak/8821A_GPS_Clock_User_Manual.pdf

Regards,
Dave.

 --
 
 Message: 7
 Date: Thu, 15 Nov 2007 09:56:09 -0700
 From: Frequency Standards  Services
   [EMAIL PROTECTED]
 Subject: [time-nuts] Trak 8426-1 manual
 To: Time Nuts List Time-nuts@febo.com
 Message-ID: [EMAIL PROTECTED]
 Content-Type: text/plain; charset=iso-8859-1
 
 Does anyone out there in Time Nuts land have a service/operation manual for a 
 TRAK 8426-1?
 Thanks, Chuck Norton
 

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Re: [time-nuts] Isotemp OCXO (David Smith)

[David Smith]

); SAEximRunCond expanded to false
Errors-To: [EMAIL PROTECTED] RETRY

Sorry gents.

I repeated my testing to make sure I hadn't messed up - and indeed it 
appears that I had!  I tried grounding the EFC input to the OCXO, and it 
immediately moved down about 7Hz.  Not sure what I did wrong before.

Back to further testing.

Regards,
Dave
VK3HZ

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[time-nuts] Isotemp OCXO

[David Smith]

); SAEximRunCond expanded to false
Errors-To: [EMAIL PROTECTED] RETRY

Hi,

I've built a GPSDO using an Isotemp 10MHz OCXO (134-10) as available on 
eB*y a while back.

The OCXO seems to be very slow to respond to changes in the control 
voltage.  I assume there is an internal RC filter or similar to improve 
performance.  However, the datasheet makes no mention of this.  Does 
anyone know what the time-constant of the control input might be?

Regards,
David Smith

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Re: [time-nuts] Failure mode in GPS receivers

[David Smith]

Hi Bruce,

Bruce Lane wrote:

  snip 

 P.S. Have you got any software for yours?  I've got a User Manual
 PDF for mine if that helps.
 
 For the Trak? I've got an archive file with the last release of
 firmware, if that's what you mean. Trak was nice enough to send such
 my way after some protracted begging.

I was more thinking (PC) application software.  I've seen mention of 
TrakGPS, but a web search turns up, I suspect, a different product.

Do you have any suggestions on how it might be set up as a time ref on a 
network?

Regards,
David Smith.


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Re: [time-nuts] Failure mode in GPS receivers

[David Smith]

Bruce,

I've owned a Trak Systems 8821 for over a year, and had a problem with 
the antenna side.  Yours may be different.

My unit is designed to work with a powered antenna, and it feeds 12V up 
the coax to power it.  Apparently this is the standard voltage for TNC 
antenna connections - the smaller MCX etc. are 5V standard.

In my ignorance, I initially connected one of the regular mouse type 
antennas to it that requires 5V.  The antenna worked OK for months, and 
I only discovered the error when I was fitting another more permanent 
antenna.  Strangely, the mouse no longer works on 5V, but seems to get 
by on 12V.

Because most powered antennas these days seem to be 5V, I modded the 
Trak with a 78L05 in the antenna power circuit to match.

So, what you could have done is fried the port on your splitter with the 
12V?  Just a guess.

Regards,
David Smith.

P.S. Have you got any software for yours?  I've got a User Manual PDF 
for mine if that helps.

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