Re: [time-nuts] Time nut over from the old days

[John Franke]

I still use them, both the Bliley and James Knights versions. Especially like 
them for 100 KC crystals.

John Franke
WA4WDL

> On February 28, 2018 at 12:22 PM Pete Lancashire <p...@petelancashire.com> 
> wrote:
> 
> 
> https://photos.app.goo.gl/gIw4P1RQHPk2t4K33
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Re: [time-nuts] HP5065 - Some OP-Amp, FB and Teflon

[John Franke]

Great story! Congratulations on the recovery and restoration.

John WA4WDL

> On November 28, 2017 at 1:52 PM Ulf Kylenfall via time-nuts 
>  wrote:
> 
> 
>  
> All,
> Your comments regarding my hobby project are appreciated.
> The story behind the first 5065A that I was able to bring back to life was 
> that I encountered it when I was 13 yearsold in 1968, taking part in the 
> schools intern programme (first experience about what a job was and what 
> engineersdo in their work). I was given a tour of the Onsla Space Observatory 
> and the 5065A, the pride of the observatorywas shown to me. (I was not 
> allowed to touch it.) In the late 90's it was decomissioned because of the 
> burned Rubidium cavityheater and would eventually have gone into the 
> recycling container had I not salvaged it almost 50 years later.
> 
> (I found the OPA111 link in one of the answers in the thread and purchased 
> the remaining 3 pieces.)
> Ulf - SM6GXV
> 
> 
> 
> 
> 
> 
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Re: [time-nuts] Deaf Z3801

[John Franke]

Try:


Shut off power to the GPS receiver

Disconnect the GPS antenna downlead

Reapply power to the GPS receiver

Enter  :GPS:INIT:DATE 2017,01,01 (The only space is between DATE and 2017)

Reconnect the GPS antenna downlead and wait


John

> 
> On November 14, 2017 at 10:43 PM Bob Bownes  wrote:
> 
> I put my 3801 back in service the day before yesterday, or tried to. It’s 
> been on the shelf for about a year (off).
> 
> I powered it up, and while it sees a few sats, it will not acquire any. 
> Changing to a known good antenna (off the NTP server) makes no difference.
> 
> Anyone seen the behavior before? The location data is good, but the 
> time/date are way out.
> 
> Thanks!
> Bob
> 
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Re: [time-nuts] Frequency counter questions

[John Franke]

And there was the HP 540 and the HP 2590B... I still use a HP 2590B for 
frequency measurement and in conjunction with a HP 851B display as a spectrum 
analyzer.


John WA4WDL

> 
> On June 8, 2017 at 8:35 AM Scott McGrath  wrote:
> 
> The heterodyne trick has been done before the first
> 'Modern' frequency counter the HP 5245 used plug ins to extend its range 
> to 18 Ghz by doing exactly that. The plug in contained a tunable LO mixer and 
> indicator to show tuning lock
> 
> These were a pain to use but they beat the 'frequency meters' by a mile
> 
> Content by Scott
> Typos by Siri
> 
> > > 
> > On Apr 26, 2017, at 2:52 PM, al wolfe  wrote:
> > 
> > such
> > 
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Re: [time-nuts] Relationship of frequency to stability

[John Franke]

There is no direct relationship between frequency and stability. For any given 
frequency, the stability is determined to a large extent by the technology used 
for the oscillator. For instance, at 1 kHz, a quartz crystal is normally more 
stable than a tuning fork which is normally better than a LC circuit which is 
normally better than a RC circuit. And even amongst a set of oscillators the 
stability is determined by the stability of the individual components, the 
design of the oscillator, and environment factors. There have been pendulum and 
tuning fork clocks better than some quartz crystal clocks. Quartz crystal 
clocks eventually became more stable than free pendulum clocks which were 
limited by gravitational variations. Some quartz oscillators are better than 
ammonia atomic clocks. I have tuning forks at 1 kHz that are more stable than 
some crystal oscillators and microwave klystrons. Stability is more related to 
the quality of the parts, the design of the oscillators the base tech
 nology and the control of environmental factors than to the frequency. 
Examples can be found where an oscillator based on older technology outperforms 
a newer potentially more stable technology through attention to detail in the 
construction and operation. 

Hope this helps!

John  WA4WDL
> On June 7, 2017 at 10:25 AM John Sloan  wrote:
> 
> 
> 
> SHORT VERSION: I’ve been trying to figure out what the relationship is 
> between frequency and stability - if there is one - that is, why oscillators 
> with higher frequencies tend to be more stable.
> 
> LONG VERSION: I got into this by building a home-brew NTP server using a 
> cesium-disciplined oscillator, specifically a Jackson Labs GPS-disciplined 
> oscillator board that incorporates a Microsemi Chip Scale Atomic Clock. I 
> started thinking about the 9,192,631,770Hz oscillator in the CSAC, the quartz 
> oscillator in my $10 Casio wristwatch that is perhaps 32768 Hz, the 8 Hz 
> balance wheel in my Rolex GMT Master II, the 6 Hz balance wheel in my 
> Hamilton Jazzmaster, and the maybe 5 Hz of some of my less expensive 
> mechanical wristwatches. In my personal experience, there is a correlation. I 
> kinda figure this has to do somehow with the Q calculation, but it’s just not 
> happening for me, math-wise. For example, arguments about relative error seem 
> to cancel out because of the greater number of ticks per second. I’m putting 
> a talk together and would like to rationalize this somehow. Googling hasn’t 
> provided any insights so far. Links to references would be great. Thanks for 
> any pointers!
> 
> --
> J. L. SloanDigital Aggregates Corp.
> +1 303 940 9064 (O)3440 Youngfield St. #209
> +1 303 489 5178 (M)Wheat Ridge CO 80033 USA
> jsl...@diag.comhttp://www.diag.com 
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Re: [time-nuts] Need schoolin PPM vs E to the umth?

[John Franke]

1 PPM is one part per million or 1 X 10^-6.  An uncertainty of 1 PPM for a 
frequency of 1 MHz would mean an uncertainty of 1 Hz.  At 3.5 MHz, the 
uncertainty would be 3.5 Hz.  An accuracy of 1 X 10^-10 is 10,000, or 10^4, 
times better than 1 X 10^-6. 1 X 10^-10 is equivalent to 0.0001 PPM.

John WA4WDL

- Original Message - 
From: n3...@aol.com
To: time-nuts@febo.com
Sent: Wednesday, December 31, 2008 10:56 AM
Subject: [time-nuts] Need schoolin PPM vs E to the umth?


 So can any one bring it down a few clicks and explain the accuracy thing 
 to this balding hippie?

 I'm leaning towards ham radio applications. GPSDO are rated in one way 
 like 1 X 10 to something. Ham radios are coming with High Stability 
 oscillators that are rated in ? PPM.

 In laymen's terms what do those numbers mean and how do they relate to 
 each other?

 Hope this doesn't start to much controversy on the board.

 73
 Chris



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[time-nuts] CHU to QSY

[John Franke]

CHU TO QSY JANUARY 1ST
The CQ Newsroom reports: Canadian time/frequency standard station CHU -- a 
fixture for decades on 7335 kHz -- will change frequency to 7850 kHz at  
UTC on January 1, 2009. The move comes as a result of the International 
Telecommunication Union's decision in 2007 to expand the 40-meter ham band 
in Europe and Africa (Region I) to 7000-7200 kHz. It was previously 
7000-7100 kHz, with -- as every 40-meter DXer knows -- international 
broadcasting allocated from 7100-7300 kHz.

As part of the 40-meter expansion, the international broadcast band was 
shifted to 7200-7350 kHz. As broadcasters began relocating, CHU on 7335 
began experiencing significant interference. Thus, officials at Canada's 
National Research Council which operates CHU, decided to move the 
time/frequency standard station's transmissions to 7850 kHz as of the 
beginning of 2009. The complete NRC announcement (English version) is online 
at:

http://inms-ienm.nrc-cnrc.gc.ca/common_files/stories/chu/communique_e.pdf


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Re: [time-nuts] Wenzel Associates 100 Mhz osc

[John Franke]

If labeled 12V, that means 12V, not 12V automobile.

- Original Message - 
From: [EMAIL PROTECTED]
To: time-nuts@febo.com
Sent: Wednesday, December 03, 2008 1:33 PM
Subject: Re: [time-nuts] Wenzel Associates 100 Mhz osc


I have some drive time so I might give Wenzel a call and see how it goes.

 Meanwhile I looked around some more and found some with PTI oscillators. 
 The pins are laid out in a square where as the Wenzel unit is in a 
 straight row. The attached cable is the same with the same colors so I'm 
 going to guess I can find the power and control leads. I'll make a test 
 set up and start playing.

 Got a few questions.

 When it says 12 volts, most times 13.8~ 14 should be fine? These are 
 labeled 12 volts.
 Will that 12 volts need to be regulated?

 Do the specs look?decent?

 Here is a link to the PTI unit.?

 http://www.mtronpti.com/pdf/xo5051_datasheet51607.pdf

 Thanks
 Chris





 -Original Message-
 From: [EMAIL PROTECTED]
 [mailto:[EMAIL PROTECTED] On Behalf Of [EMAIL PROTECTED]
 Sent: Monday, December 01, 2008 2:00 PM
 To: time-nuts@febo.com
 Subject: [time-nuts] Wenzel Associates 100 Mhz osc

 I stumbled across a 100 Mhz oscillator. It comes from a
 Harris Constellation RX/TX.

 According to the website part number is proprietary. So I
 thought I would ask here or any info.

 Here is what is printed on it from top to bottom.

 500-06769D
 ISSUE 02
 PPD 786-020590-053
 100 Mhz
 +12 VDC
 0105-0201SSRG

 It has a SMA female or 100 Mhz out and 4 pins for power and AFC?

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Re: [time-nuts] WWV / WWVH / WWVB

[John Franke]

The ticks are diferent frequency tines.

From: http://tf.nist.gov/timefreq/general/pdf/1383.pdf :

The most frequent sounds heard on WWV and WWVH are the seconds pulses. These 
pulses

are heard every second except on the 29th and 59th seconds of each minute.

The first pulse of each hour is an 800 ms pulse of 1500 Hz. The first pulse 
of each minute

is an 800 ms pulse of 1000 Hz at WWV and 1200 Hz at WWVH. The remaining 
second

pulses are short audio bursts (5 ms pulses of 1000 Hz at WWV and 1200 Hz at 
WWVH)

that sound like the ticking of a clock.


John WA4WDL

- Original Message - 
From: Brad Stockdale [EMAIL PROTECTED]
To: time-nuts@febo.com
Sent: Thursday, November 20, 2008 1:40 PM
Subject: Re: [time-nuts] WWV / WWVH / WWVB


 Hello all,

Thank you to everyone that has helped (and some that continue to
 help) me with my GPSDO equipment post... I've got a few leads out
 there and hopefully I'll be able to get ahold of some of these units
 soon... I really am looking forward to getting to work with some other 
 GPSDO's.

Anyway, on to the reason for this post... I'd like to get some
 receivers so I can HEAR and USE the WWVB, WWV, and WWVH signals... I
 know that HEARING them may not be a 'normal' request, but I just
 would like to monitor the audio as well as being able to decode the 
 signals...

I guess the first thing to take care of is receiving the signals.
 Can anyone recommend decent receivers for these stations? I guess the
 list of frequencies would be:

 o WWVB = 60 KHz
 o WWV  = 2.5 MHz, 5 MHz, 10 MHz, 15 MHz, or 20 MHz
 o WWVH = 2.5 MHz, 5 MHz, 10 MHz, or 15 MHz

Hmm, I just noticed that WWV and WWVH overlap... How in the heck
 do you differentiate between the two stations if they broadcast on
 all the same channels?

Anyway, I wouldn't mind a kit type of project that would let me
 receive these signals... Maybe I'll check out Ramsey Electronics,
 Rainbow Kits, Velleman, et al. Surely one of them has kits for these
 broadcast ranges.

Can anyone suggest a kit, or project listed online with
 schematics and parts lists, or I guess even reasonably priced commercial 
 units?

If I can't get radios that have built in decoders for these
 stations, I'd be happy just receiving their audio and then trying to
 build my own decoder using a PIC or something...

Thanks for any advice.

 Brad



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Re: [time-nuts] Trimble Thunderbolt temperature judgment call

[John Franke]

The problem is knowing how much insulation.  If you use too much insulation, 
the Thunderbolt will overheat.  I would just block any direct drafts and let 
the unit do what it was designed to do.

John  WA4WDL

- Original Message - 
From: Mike Naruta AA8K [EMAIL PROTECTED]
To: time-nuts@febo.com
Sent: Wednesday, November 19, 2008 1:34 PM
Subject: [time-nuts] Trimble Thunderbolt temperature judgment call




 I love my new Trimble Thunderbolt.
 Thank you TAPR and Time-Nuts!


 I was thinking of putting insulation
 all around the Thunderbolt to thermally
 stabilize it.  It's in my basement and
 the temperature there rarely gets above
 18 C.

 That would also help with my dedicated
 power supply, as the 12 volt sags when
 the Thunderbolt is started.  The power
 supply is beautiful one from a 1985 HP
 fiber optic mux.


 The manual says that operating temperature
 is up to 60 C.  If extra-insulated, is the
 oven plus other power going to raise the
 whole unit temperature too high?

 Would insulating the Thunderbolt and
 raising its temperature lead to a shorter
 MTBF?

 Should I tuck some foam around the oven
 instead?

 Should I just run it ambient and let the
 oven do all the work?


 Mike - AA8K


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Re: [time-nuts] CHU: do not stay tuned...

[John Franke]

Thanks for the heads up!

John WA4WDL

- Original Message - 
From: David McGaw [EMAIL PROTECTED]
To: Discussion of precise time and frequency measurement 
time-nuts@febo.com
Sent: Wednesday, November 19, 2008 3:06 PM
Subject: [time-nuts] CHU: do not stay tuned...


 It appears that CHU on 7.335MHz will soon be moved.  While CNRC can
 keep transmitting on the frequency, so can broadcasters in other
 countries now use it.  I have been hearing World
 Harvest Radio WHRI in the United States broadcasting on top of it at
 times.  The word I got from NRC-INMS is that there will be an
 announcement soon of a frequency change.

 Be ready to retune,

 David McGaw



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Re: [time-nuts] How to get 32.768KHz from 10MHz.

[John Franke]

The only thing that comes to mind is to divide the 10 MHz by 250 
(5x5x10) and then use a phase locked loop to multiply by 8192.  Of 
course the PLL would best control a varactor with a clock crystal vice 
controlling an RC oscillator.  Other divisor multiplier pairs are: 
125/4096, 625000/2048, 312500/1024, 156250/512, and 78125/256.

John  WA4WDL

- Original Message - 
From: Max Skop [EMAIL PROTECTED]
To: time-nuts@febo.com
Sent: Wednesday, July 23, 2008 10:09 AM
Subject: [time-nuts] How to get 32.768KHz from 10MHz.


 How does one get a 32.768KHz signal from our 10MHz reference.
 There does not appear to be a nice divide ratio to do this.
 With a locked 32.768KHz signal one could lock the oscillator of  any of 
 the cheap (low cost) LCD clocks that are available with nice big digits, 
 temperature sensors and calendars, etc.
 Any suggestions on how to do it??

 Regards
 Max

 ps. I got sucked in good. Six months ago all I had was an HP 10811 and now 
 I have another crystal oscillator, two rubidiums and a Trimble GPS.
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Re: [time-nuts] Thunderbolt SV and AMU Signal levels

[John Franke]

Variation of +/- one count in the last digit is normal for any counter.  It 
is caused by a slight shift between the counter gate and the input signal. 
The longer the time between digit changes, the more stable the phase between 
the unknown and the counter gate.

John  WA4WDL

- Original Message - 
From: David Ackrill [EMAIL PROTECTED]
To: Discussion of precise time and frequency measurement 
time-nuts@febo.com
Sent: Tuesday, July 22, 2008 7:14 PM
Subject: [time-nuts] Thunderbolt SV and AMU Signal levels


 Sorry to be a bore, but like any kid with a new toy I'm facinated by the
 changing values on the display...

 What do the values under SV and AMU mean?

 Maybe I should recognise them from other GPS satellite days, but they
 don't seem to be values that I remember.

 I'm sure it all means that they are to the north, south, east or west of
 here and to do with signal strength to my location or how good, or bad,
 the lock to the satellites is..  But, nothing that I can remember, to be
 honest...

 The 10MHz output seems, as far as my old Multifunction Counter is
 concerned, to be to 10.0MHz within +/-0.1 MHz.

 The display showing 10.3 to 10.4 MHz all evening.

 So, my guess is that my poor old counter is +/- 10Hz out, but that may
 be due to the age and non-calibration of my frequency counter over the
 years.

 Or... The Thunderbolt 10MHz output is moving up and down by 0.1 MHz
 within a 10MHz band.

 This is where I start to get to grips with the spectrum analyser that a
 friend of mine lent to me.  I hope...

 Dave (G0DJA)

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Re: [time-nuts] Home built Ammonia cell std !! / Home built cesiumclocks???

[John Franke]

Now that is something I am interested in doing.  I finally secured use of a 
diffusion pump at a local university and expect to be making my first sealed 
all-glass absorption cells this fall.  The ammonia pressure needs to be 
around 8-10 microns.  I will be trying for a double pass cell giving a pass 
length between 10 and 12 feet.  The first ammonia atomic clock used a path 
length of 33 feet.  The cell was made from waveguide and did not hold a 
charge due to leaks or the ammonia reacting with the gold plated waveguide. 
I believe the best ammonia based standard was only good to 10 ^ -8 in 
frequency stability.

John WA4WDL

- Original Message - 
From: Luis Cupido [EMAIL PROTECTED]
To: Discussion of precise time and frequency measurement 
time-nuts@febo.com
Sent: Sunday, June 29, 2008 11:40 AM
Subject: [time-nuts] Home built Ammonia cell std !! / Home built 
cesiumclocks???


 We dont get much info/comments about this
 But what would an ammonia cell standard be able to do.
 I mean frequency/time wise.

 Maybe easier and simpler ?
 comments ?

 Luis Cupido.
 ct1dmk.

 (I understand the frequencies are much higher
 but that is not a problem, at least for me).

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Re: [time-nuts] Home built Ammonia cell std !! / Home built cesiumclocks???

[John Franke]

No, I am talking about the 1948 gas absorption design by Lyons, not the 
ammonia MASER.  There is no state-selection.  There is no flowing gas 
molecules.  There is no quadrapole device.  It is a simple oscillator locked 
to the attenuation dip in an absorption cell.  Once built, there is no gas 
replenishment or need for additional pumping.  But, the accuracy is limited. 
By the way, Lyons cell path was 25 feet not 33 feet as I had thought.

John  WA4WDL

- Original Message - 
From: Magnus Danielson [EMAIL PROTECTED]
To: time-nuts@febo.com
Sent: Sunday, June 29, 2008 1:26 PM
Subject: Re: [time-nuts] Home built Ammonia cell std !! / Home built 
cesiumclocks???


 From: John Franke [EMAIL PROTECTED]
 Subject: Re: [time-nuts] Home built Ammonia cell std !! / Home built 
 cesiumclocks???
 Date: Sun, 29 Jun 2008 12:20:28 -0400
 Message-ID: [EMAIL PROTECTED]

 Now that is something I am interested in doing.  I finally secured use of 
 a
 diffusion pump at a local university and expect to be making my first 
 sealed
 all-glass absorption cells this fall.  The ammonia pressure needs to be
 around 8-10 microns.  I will be trying for a double pass cell giving a 
 pass
 length between 10 and 12 feet.  The first ammonia atomic clock used a 
 path
 length of 33 feet.  The cell was made from waveguide and did not hold a
 charge due to leaks or the ammonia reacting with the gold plated 
 waveguide.
 I believe the best ammonia based standard was only good to 10 ^ -8 in
 frequency stability.

 More like 5E-11 both in cavity pulling and collision effects. Cavity
 pulling was reduced in 1961 by means of automatic cavity tuning.

 Recall that you do state-selection on the ammonia beam. An electrostatic
 quadrapole configuration was used. Just like a Hydrogen maser.

 Cheers,
 Magnus

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Re: [time-nuts] Piezo Little Wonder OCXO

[John Franke]

I have two PIEZO 10.230 MHz crystal oscillators in the same style package as 
the 10811.  But the oscillator in question is for 10.238 MHz.

John  WA4WDL

- Original Message - 
From: Jim Lux [EMAIL PROTECTED]
To: Discussion of precise time and frequency measurement 
time-nuts@febo.com
Sent: Friday, May 30, 2008 12:47 PM
Subject: Re: [time-nuts] Piezo Little Wonder OCXO


 At 08:33 AM 5/30/2008, you wrote:
Early GPS receivers used a 10.23 MHz time base.
Probably related to 2^10-1.


 yep.. the chip rate for the C/A code is 1.023 Megachips/second, the P
 code is 10.23 Megachips/second, and the L1 frequency (1575.42) is
 exactly 154 times the 10.23 MHz, the L2 is 120 times.
 So you can see that having a 10.23 MHz oscillator is a handy thing in
 a GPS receiver, especially if you can discipline it with the received 
 signal.

 These days, one might choose a reference oscillator somewhat higher,
 so that when you do your 1bit A/D of the signal, you get many
 samples/chip, and so that the signal directly aliases to somewhere
 convenient. A lot of receivers use a sampling clock such that you get
 1 bit I and Q samples at a convenient sample rate.  4*10.23 would
 work nicely, eh?  40.92 MHz



Some GPS manufacturers approached HP about making
a 10811 on 10.23 MHz.  There is a circuit modification
for 10.23 MHz and some crystals were made (I
have some somewhere).  However, I don't believe
any 10.23 MHz 10811's were sold.  This unit was
probably intended to meet the need not filled by HP.



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Re: [time-nuts] HP Z3801A Communications

[John Franke]

You might open up the case and check to see if the unit has already been 
changed to RS-232, one of mine was.

John  WA4WDL

- Original Message - 
From: Richard W. Solomon [EMAIL PROTECTED]
To: time-nuts@febo.com
Sent: Saturday, May 17, 2008 3:48 PM
Subject: [time-nuts] HP Z3801A Communications


I picked up one at a Flea and need to know how to access the internal
 status software using my old 486 laptop running WIN98SE. I have not
 done the RS-422 to RS-232 conversion yet.
 I think I need to do a System Re-Set.

 Thanks, Dick, W1KSZ

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Re: [time-nuts] Buffering the 1pps output from a Z3801A

[John Franke]

See;  http://www.realhamradio.com/sidecar.htm

John WA4WDL

- Original Message - 
From: Peter Vince [EMAIL PROTECTED]
To: time-nuts@febo.com
Sent: Wednesday, March 26, 2008 9:29 AM
Subject: [time-nuts] Buffering the 1pps output from a Z3801A


 Bruce, et al,

 The 1pps output of an HP Z3801A and Trimble Thunderbolt is
 only available (as far as I know) as a balanced ECL signal on the
 25-pin connector, with dire warnings in the manuals about not
 earthing either side of the ECL signals.  Would you be able to advise
 on a simple buffer circuit that would allow me to drive the usual
 unbalanced 50-ohm coax please?

 Thanks,

 Peter Vince  (London, England)

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Re: [time-nuts] GPS Antenna Cable Splicing

[John Franke]

First; how long does the total length need to be?  With lower loss cables, 
10m is no problem.

Second; if you go to the trouble of adding a length of cable, it would be 
best if you replace as much of the 5m cable as possible with lower loss 
cable rather than just adding to the 5m cable.

John  WA4WDL

- Original Message - 
From: Bruce Griffiths [EMAIL PROTECTED]
To: Discussion of precise time and frequency measurement 
time-nuts@febo.com
Sent: Saturday, March 01, 2008 8:25 AM
Subject: Re: [time-nuts] GPS Antenna Cable Splicing


 Matthew Smith wrote:
 Hi Folks

 I'm not so hot on RF stuff (actually not so hot on anything above
 50/60Hz - only studied power stuff) so thought I should ask:

 I have a few GPS antennae here, all with 5m (15ft-ish) cables on them.
 For me, that won't get the antenna anywhere near the highest ridgeline
 of the house.  (Australian Federation Style house - lots of weird bits
 of roof all over the place.)  So, I need to extend the cable.

 1) Can I actually extend the cables, or is 5m as far as I can go - all
 these are active antennae.

 2) My normal way of extending a bit of coax would be to splice in an
 appropriate length of similar cable.  To do this, I would strip the
 outer insulation for a couple of inches on both pieces, pulling back the
 braid.  I would then strip enough of the central insulation so that I
 can solder the two cores together.  I insulate this with tape or
 heatshrink, then solder the two braids together, wrap the whole thing
 with aluminium foil and use a glued heatshrink to case the whole lot.

 I know that this method works for 10-Base2 Ethernet and UHF Television,
  but have no idea if is suitable for SHF stuff like 1.5GHz...

 3) How far apart do I need to space my GPS antennae, or can they be
 nearly touching?  I suppose it would be easier if I used a distribution
 amp (assuming such things exist at this frequency), but that sounds
 expensive.

 Cheers

 M


 Matthew

 GPS distribution amplifiers are readily available, they appear from time
 to time on ebay.
 Symmetricom 58537 4 port active smart splitters can be quite useful.
 HP/Agilent/Symmetricom 58537A, 58536A are also useful.

 The small diameter captive cable used by some GPS antennas tends to be
 somewhat lossy and it may be better to extend the length by using a
 lower loss cable.
 Your splicing technique will create a significant discontinuity in the
 cable impedance at 1.57542 GHz.
 The maximum cable length is determined by the maximum allowable cable
 attenuation between the antenna and the GPS receiver.
 A high gain active antenna allows greater cable loss than a low gain
 active antenna or a passive antenna.

 The better active antennas use a TNC, N or similar connector so you can
 use a custom length cable.

 Bruce

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Re: [time-nuts] Setting time display on SatStat to UTC

[John Franke]

Using info from K8CU; 
http://www.realhamradio.com/GPS_Frequency_Standard.htm

Issue the command:

   :diag:gps:utc?

If it returns 0 you are in GPS mode; if 1 you are in UTC

Use the command:

   :diag:gps:utc 1

followed by

   :syst:pon

to set it to UTC mode.  Some units have to be powered off to actually reset 
to UTC depending on software version.

John  WA4WDL


- Original Message - 
From: Peter Vince [EMAIL PROTECTED]
To: time-nuts@febo.com
Sent: Thursday, February 21, 2008 11:40 AM
Subject: [time-nuts] Setting time display on SatStat to UTC


I have recently acquired a Z3801A, and it has locked up OK.  But the time
 display on SatStat is GPS time, and I can't see from the manual how to
 change it to UTC.  Can anyone help me please?

 Thanks,  Peter  (London, England)


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Re: [time-nuts] need recomendation for a portable 10mhz reference oscilator

[John Franke]

Snow is stable at its transition temperature.  Below that, it varies with 
the ambient temperature.  Snow temperatures in Greenland are often near -40 
degrees.  It is much like water.  At the boiling point, the water 
temperature is fairly stable.  Below the boiling point, the temperature of 
water follows the ambient.

I thought about using ice at one time, but a simple experiment set me 
straight.

John  WA4WDL


- Original Message - 
From: Hal Murray [EMAIL PROTECTED]
To: [EMAIL PROTECTED]; Discussion of precise time and frequency 
measurement time-nuts@febo.com
Sent: Friday, December 14, 2007 4:03 AM
Subject: Re: [time-nuts] need recomendation for a portable 10mhz reference 
oscilator



 Perhaps then this trick should be used with an ovenized oscillator of
 lesser quality, since it sounds like the E1938A will work just fine if
 stuck in the snow.

 Snow is probably a stable temperature.


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




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Re: [time-nuts] Upgrading possibilities for more accurate, precise stable mark ii

[John Franke]

Are you positive there are no locations at your apartment that can receive 
GPS.  I live in an apartment and can get suitable signals with hockey puck 
antennas mounted on four-inch square ground planes placed in various 
windows.  The ground planes are horizontal.  I thought about tilting the 
ground planes, but too much thermal ground noise is received.

John  WA4WDL

- Original Message - 
From: Ronald Held [EMAIL PROTECTED]
To: time-nuts@febo.com
Sent: Friday, December 14, 2007 8:34 PM
Subject: [time-nuts] Upgrading possibilities for more accurate,precise 
stable mark ii


 Greetings:
  I do not know how to properly add to a thread, so I am resubmitting
 this I do not have the necessary circuit skills, so i would have to
 buy preassembled components. I have a
 Endrun Precis Cf OCXO discipline via CDMA signals, which go into a display
 unit driven by a STAMP microprocessor(AFAIK, since Bob build and
 programmed it.
  Given that I cannot receive GPS signals in my apartment, what are my 
 options?
 Is it to go to a Rb/Cs standard and counter? if that is so how do I
 periodically sync up with a more accurate time source?
   Ronald

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Re: [time-nuts] Super stable BVA Quartz resonators... BVA??

[John Franke]

Try:

Boîtier à Vieillissement Amélioré

John WA4WDL

- Original Message - 
From: John Ackermann N8UR [EMAIL PROTECTED]
To: Discussion of precise time and frequency measurement 
time-nuts@febo.com
Sent: Friday, December 07, 2007 11:20 AM
Subject: Re: [time-nuts] Super stable BVA Quartz resonators... BVA??


 Michael Baker wrote:

 I have found out how a BVA resonator is fabricated, but
 I have not discovered what the acronym BVA stands for.

 I suspect that the B in BVA may refer to Raymond Besson
 the discoverer of the BVA quartz resonator, but I
 have not been able to confirm that.

 Can anyone on the list shed some light on this?

 I don't have the exact translation handy, but I ran across something
 indicating that BVA was an acronym in French for something like
 improved aging rate.

 John

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Re: [time-nuts] Improving the stability of crystal oscillators

[John Franke]

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

This is something I have thought about but never did any experimentation. 
With the low cost and increased availability of thermoelectric coolers, I am 
interested in pursuing this concept.  The unfortunate thing is that the 
crystals are ground for 25C or the higher turnover temperature point.  If 
someone has a crystal that has drifted, it may be a good candidate for 
experimentation.  Another thought would be to let the crystal operate at its 
natural frequency, divide it down to 1 or ten Hz and then phase lock a more 
convenient crystal frequency to the low pulse rate.  The idea is to save an 
otherwise aged and well performing crystal.

John  WA4WDL

- Original Message - 
From: Tom Van Baak [EMAIL PROTECTED]
To: Discussion of precise time and frequency measurement 
time-nuts@febo.com
Sent: Monday, October 15, 2007 10:12 PM
Subject: Re: [time-nuts] Improving the stability of crystal oscillators


 As far as I can tell, temperature curve plots for quartz typically
 show both an upper and a lower turnover point (for example,
 see the pages below). Since the upper is well above maximum
 ambient, it makes sense that this point is used in O[ven]CXO.

 The question is -- does anyone know if the lower turnover point
 (LTP) is ever used? I ask because I heard that a quartz oscillator
 might have slightly better short-term stability at the LTP compared
 to the UTP. If so, this might argue for the extra trouble of using
 TEC for cooling in some low-noise applications.

 /tvb

 http://www.ieee-uffc.org/freqcontrol/tutorials/vig3/vig3_files/slide0164.htm
 http://www.ieee-uffc.org/freqcontrol/tutorials/vig3/vig3_files/slide0306.htm


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Re: [time-nuts] Setting Rubidium to match GPS source

[John Franke]

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

I would like to see the details.

John  WA4WDL

- Original Message - 
From: Pete [EMAIL PROTECTED]
To: Discussion of precise time and frequency measurement 
time-nuts@febo.com
Sent: Thursday, September 27, 2007 7:37 PM
Subject: Re: [time-nuts] Setting Rubidium to match GPS source


 Chris,

 The 3575A does NOT have adequate phase resolution to set an Rb
 source to match a GPSDO. A few, now rather old, phase meters were
 sold for this purpose, but they used a strip chart recorder to average
 phase shift over 1 to 24 hour measurement times  required great
 investments of time to use.

 I proposed a 1KHz heterodyne scheme for this very purpose on this
 list a few months ago. The scheme took a few hits for lack of state-
 of-the-art performance, but I'm still using it without suffering any
 disappointments. It does require you to have a few items of test
 equipment (readily available on eBay) which not everyone has 
 it requires some circuit construction using readily available parts.
 Except you must wind a couple of 5mH inductors on your own.

 Contact me off-list if you want more details.

 Regards,
 Pete Rawson

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[time-nuts] Need Gen Rad type 276 crystal

[John Franke]

I recently powered up a General Radio model 275 piezo-electric oscillator, 
which according to General Radio information was introduced in 1924 as the 
first commercially available crystal oscillator.  Right now I am using a 
type 376-L 1.000 MHz crystal in the oscillator.  I am looking for a type 
276, which was more the correct period crystal.  I could use any frequency 
between 900 kHz and 2300 kHz as that is the tuning range of the plug-in tank 
coil I have.  By the way, the output is approximately 300 Hz high.

Thanks,

John WA4WDL 



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Re: [time-nuts] Pendulums Atomic Clocks Gravity

[John Franke]

I recently acquired at an estate sale a compact 10 MHz 27Vdc Austron Inc., 
Sulzer model 1630 crystal oscillator, but I cannot find any data via the web 
on how to hook it up. It has a ring of nine solder terminals on the base. 
Does anyone in this group have any information?

John  WA4WDL 



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