[time-nuts] Looking for Z3801 Power Supply Board

My Z3801 power supply board has given up the ghost. It had been working well apart from an occasional Error 230 causing it to go into Holdover for no good reason from time to time which may well be related of course. Does anyone have a good power supply from an otherwise dead unit which

Re: [time-nuts] Looking for Z3801 Power Supply Board

On 5/23/2016 3:54 PM, Dave M wrote: Dan, If you haven't already found the Z3801A page at http://www.realhamradio.com/GPS_Frequency_Standard.htm, you should read it thoroughly (in your case, especialy the section on the power supply). there is a good pictorial that shows locations of all the

Re: [time-nuts] Rpair of an 8662 HP Generator

On 4/15/2016 3:38 PM, John Miles wrote: Have a look at the capacitors in the voltage divider that drives the bases of the switching transistors. There's a good chance that's your problem, and they probably need to be replaced even if not. 75-TVA1607 (Mouser p/n for Sprague TVA1607) works well.

Re: [time-nuts] 5061B Service Manual, Page 8-57 (BEAM I, if LOW)

On 7/16/2016 8:11 PM, Christopher Hoover wrote: My 5061B (with FTS tube) has a low beam current. Maybe 7 on the meter when adjusted onto the primary peak. I bought the Ops and Service manual, but my copy is missing page 8-57 (and 8-56 if that exists). Christopher, Given that Foldout Page

Re: [time-nuts] There is a Tracor 527E on ebay

On 7/15/2016 4:19 AM, Bert Kehren via time-nuts wrote: Have been using mine for over 15 years, very handy tool and using the > 1 MHz output for very high resolution measurements. Bert Kehren If anyone is in need, I have both a 572E as well as a 572A (the version with a 1" CRT display, a

Re: [time-nuts] Visiting Greenwich

Dave, it's been a few years since I was there but the Harrison clocks are not in the main part of the museum but in the Observatory which is a bit to the South and East if I remember right. Both are well worth a look, but the Harrisons are magic of course. Dan

Re: [time-nuts] HF frequency counting receiver

On 6/20/2016 11:18 AM, Mark Spencer wrote: I am quite convinced that HF Doppler shift is a real issue at times. Absolutely true Mark. I spent some time looking at this way back when and it is quite possible to observe (in Southern Calfornia) transitory phase shifts on the 10 MHz signal

Re: [time-nuts] HP5065A Rubidium questions: some progress

On 2/20/2017 4:25 PM, David Scott Coburn wrote: One odd bit is that the resistor in the transistor emitter leg measures about 350 ohms (this is R3 in my schematic). The schematic says it should be 10 ohms. This resistor is on solder posts, so it looks like a 'selected at assembly' item.

Re: [time-nuts] Vintage Frequency Measurement

On 2/11/2017 10:08 PM, Scott Stobbe wrote: I was inspired recently coming across a Lampkin 105 frequency meter, as to how frequency measurement was done before counters. Certainly zero-beating a dial calibrated oscillator, would be one approach. Google BC-221 and you may get some idea of how

Re: [time-nuts] Vintage Frequency Measurement

To put BC-221 things in perspective, the 1 Mc/s reference crystal was adjusted, according to the manual, to within 5 c/s... Things have come a ways since! Dan ___ time-nuts mailing list -- time-nuts@febo.com To unsubscribe, go to

Re: [time-nuts] TNS-BUF High Isolation, Low Noise Buffer Amp Available

For those of us who aren't scared of surface mount stuff, and maybe even prefer it, will there be any bare boards available? Dan - ac6ao ___ time-nuts mailing list -- time-nuts@febo.com To unsubscribe, go to

Re: [time-nuts] Thunderbolt spurs on 10MHz output at 100Hz and 200Hz from signal.

On 9/21/2016 9:01 AM, David C. Partridge wrote: Yes, I fear a timepod is a bit out of my budget (I can dream tho'). Over here in the UK PN measurement kit is a bit thin on the ground too. So I looked at but that seemed a little thin

Re: [time-nuts] Thunderbolt spurs on 10MHz output at 100Hz and 200Hz from signal.

On 9/21/2016 8:01 AM, David C. Partridge wrote: Looks like all I've managed to do is measure the baseline noise of the analyser. Ho-hum looks like I need something a *lot* quieter to do these measurements. Indeed Dave, yes. I made the same mistake a few years ago when I tried to compare

Re: [time-nuts] Thunderbolt spurs on 10MHz output at 100Hz and 200Hz from signal.

On 9/18/2016 5:42 AM, David C. Partridge wrote: I've just redone the measurement without the external attenuator and with 10dB attenuation set internally to the analyser. The results are attached. I suspect that you are measuring the analyser phase noise, but it's rather early in the

Re: [time-nuts] Normal operating specs of a Morion MV89?

These have been discussed before at some length. It is not just the output cap that is easily damaged by rough salvage efforts, which however are sadly common enough. There is also a frequently seen problem of bad output spectra with a lot of non harmonic related stuff in the output, not a

Re: [time-nuts] Opening an Isotemp OCXO

On 10/28/2016 9:09 AM, Peter Reilley wrote: The only document that I could find said 12 volt. Pete. The 82 series came in a lot of flavors. I have one 82-49 which is definitely 12V ( draws 0.12A when warm and maybe 0.3 when cold) and has a 5V pp square wave output at 10 MHz. It also has a

Re: [time-nuts] hp 5065A

On 10/29/2016 9:42 AM, John Ponsonby wrote: Gentlemen, I am interested in getting an old hp 5065A Rubidium frequency standard working again. I recall that if one of these units is left not running for a long time that the rubidium atoms get adsorbed onto the glass of the cell and

Re: [time-nuts] Why is holdover LED on HP 58503A not lit, when GPS lock is unlit too?

On 12/18/2016 9:34 AM, Dr. David Kirkby (Kirkby Microwave Ltd) wrote: *12 -- ---MODE Survey: 0% complete If it's still showing that after being on for five hours, maybe it needs to be explicitly told to

Re: [time-nuts] Conversion of Stanford PRS10 to RS-232 Communication

On 4/3/2017 1:05 PM, Philip Jackson wrote: I understand that the PRS10 Rubidium units either talk to the host device via a RS-232 serial command language or via analog values using the same set of pins in both cases. Does anyone know how the format can be changed? The manual doesn't say

Re: [time-nuts] TAPR Oncore M12+ kit

Worth looking closely at these if you've bought one. On mine, apart from the connector to the DB9 being pulled off and some pins bent, which I could fix, there are two tiny SM ceramic caps that have been knocked off the M12 GPS board, both hanging by one of the detached PC traces. This I

Re: [time-nuts] Fwd: HP10811 Oscillator Thermal Fuse

As I reported the last time this subject came up, or maybe the time before, the only time I had an open thermal fuse was in a 10811 that had an open thermistor. I was able to replace that and get the OCXO working, but if the fuse had been replaced with a wire link I'm sure the entire oven

Re: [time-nuts] poor-man's oven

The attached plot shows the sort of improvement in warm up time and stability of a simple "oven" made by attaching a Darlington heater transistor and thermistor to a Crystek 100 MHz oscillator, adjusted to set the osc temp to around 35C and wrapping it all in foam. In this application, a DDS

Re: [time-nuts] HP 3048A Phase Noise System needs a new home

On 5/1/2017 4:14 PM, Dan Rae wrote: Basic system comprising: 3561A Analyzer 11848A Interface 11729C Carrier Noise Test Set with all extras to 18GHz Basic system is spoken for. Thanks to all and to tvb for being there. Dan ___ time-nuts mailing

[time-nuts] HP 3048A Phase Noise System needs a new home

Basic system comprising: 3561A Analyzer 11848A Interface 11729C Carrier Noise Test Set with all extras to 18GHz Bunch of HPIB and Coax cables as needed and pretty much all the paper manuals, several shelf feet. An -hp- 2225A hpib printer which I couldn't get to work in the system as I had

Re: [time-nuts] R XSRM Rubidium Standard

On 9/12/2017 5:58 AM, GandalfG8--- via time-nuts wrote: A friend of mine has bought a just out of calibration R & S XSRM Rubidium standard from one of the so called "recyclers" on Ebay. Nigel / David, Sorry to hear of your "bargain".   However I doubt very much that the lamp was made by R

[time-nuts] A Lady H mystery

I've been trying to get LH (V5) to control and set position for the GPS board in one of my GPSDOs.  It is a Trimble "Lassen Ace III" Rx according to itself.  LH auto detects it quickly enough, reports it as a TSIP receiver but then shows a screen saying "LOG: OFF", a blank graph grid and

Re: [time-nuts] Motorola GPS Antenna?

On 5/21/2018 8:24 AM, Clint Jay wrote: Found on eBay with no further information, can anyone identify? https://www.ebay.co.uk/itm/EX-MOD-Motorola-Antenna/323177970249?hash=item4b3ee87a49:g:tHIAAOSwUCZavUAe It looks like the standard "Marine" antenna, probably 5v, loads of gain (30 dB?), like

[time-nuts] FS -hp- 5370 "Time Nuts Processor" board + +

Bought some time around 2013 and not used if this is any use to anyone please contact me direct.   No reasonable offer refused.  I also have a 5370B to go with it but that will have to be picked up in Santa Monica CA.  $100 with an A parts unit and a few spare boards rescued from the gold

Re: [time-nuts] FS -hp- 5370 "Time Nuts Processor" board + +

Board is spoken for, thanks, Dan ___ 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.

Re: [time-nuts] Antennas for Symettricom 2500 Time Source

On 6/9/2018 12:05 PM, Bruce Hunter via time-nuts wrote: Has anyone stumbled across the 12V antennas for Symmetricom 2500 Time Source units. I have a Symmetricom "Replacement GPS Antenna Kit" P/N 142-614-50 which consists of "one wide range 5-12 VDC L1 antenna" and 50 feet of Belden 9104 coax

Re: [time-nuts] Racal 9475 Rubidium

On 5/1/2018 2:18 AM, Paul Bicknell wrote: As I have just bought a Racal 9475 Rubidium and it has problems Is there any stock faults ? What is the life of the rubidium standard? The Racal manual for this only covers the support stuff.  Your problem is almost certainly with the Rb

Re: [time-nuts] Racal 9475 Rubidium

On 5/3/2018 9:55 AM, Bob kb8tq wrote: Hi You *really* need to keep the baseplate of the FRK series devices down. Their reliability drops quite a bit as you go from 40 to 50 to 60 C on the baseplate. I would avoid boosting the input voltage without a very good heatsink ( or heatsink + fan )

Re: [time-nuts] Racal 9475 Rubidium

On 5/3/2018 7:38 AM, Adrian Godwin wrote: What sort of heatsink does it need ? Do you need the original part or would a lightly-machined generic module do ? At the time, at least in the UK, it was a very common extrusion, often used for power supplies etc., and in fact I see two on the back of

Re: [time-nuts] Tracor 527 CRT

On 4/4/2018 2:28 PM, ew via time-nuts wrote: Lat year some one from the UK asked me about a 1 inch CRT for the Tracor 527. I sent David Partridge one at the time, so he is now happy. Dan ___ time-nuts mailing list -- time-nuts@febo.com To

Re: [time-nuts] Any guesses as to how Citizen is claiming ±1 second/year with using this AT-cut 8.4MHz XTAL?

Way back in 1960 something Braun in Germany made a little alarm clock using a 4.194304 MHz crystal which could reach this level of accuracy.  I had one and it certainly met the Harrison level of timekeeping when I used it for navigation.  I think that the crystal cut used had a temperature

Re: [time-nuts] Introduction & GPSDO Question

I'm mainly interested in creating a reasonable 10mHz standard for my various pieces of test equipment here at home. To that end I've purchased and received an Ebay "Trimble Inside" GPSDO unit, described as model 57963. No instructions or manual were included with the hardware. The unit has

[time-nuts] Ref Voltage for GPSDO?

I've been trying to use an Oscilloquartz 8663 in my recently resurrected Shera GPSDO, but the built in V ref of the 8663 has major random instabilities.  I've tried another (MTI) ocxo in it's place but that one has galloping ageing problems (the equivalent of 10 to 20 milliHertz per day) and

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