Re: [time-nuts] A Symmtricom GPSDO Board

More likely the missing GPS receiver board is installed over the ground plane. Bruce On Sunday, 5 June 2016 4:11 PM, Hui Zhang wrote: Dear group:     Does anyone familiar with this Symmtricom GPSDO board? I have searched on internet but I have not found any manual or

[time-nuts] A Symmtricom GPSDO Board

Dear group: Does anyone familiar with this Symmtricom GPSDO board? I have searched on internet but I have not found any manual or technical infomation about it. It seems can use a RS-232 cable and simple SCPI or serial command to control it, just like HP 58540 or other GPSDO board that I

[time-nuts] HP 106a oscillator connectors question

Thanks for all the info. They are the 1/4-32 (S-93 compatible) Microdot !!! I ordered a double ended cable and will cut it in half to give me the two connections I need (5Mhz out and EFC in). Cheers, Corby ___ time-nuts mailing list --

Re: [time-nuts] Mystery hp Ovens For Sale

On 06/04/2016 08:24 AM, Bob Camp wrote: Not accurate, but at least a hand waving sort of number: Bob, It serves a crystal calibrator marker on each 100 kHz of a ten inch dial 600 kHz wide. It is good enough for the job, but not really in the time-nuts realm, except for the accuracy

Re: [time-nuts] How to get unknown frequency quartz crystals oscillating

Hi There are two things you may be talking about: 1) The pressure springs on things like FT-243 holders, they are generic springs. 2) The connection leads on plated blanks, they are indeed strange *and* soldering to the blank is a big problem. I’m guessing you are in bucket number 2. Bob

Re: [time-nuts] How to get unknown frequency quartz crystals oscillating

Hi George: A Crystal Activity Meter is the most straight forward way: http://www.prc68.com/I/Xam.html -- Have Fun, Brooke Clarke http://www.PRC68.com http://www.end2partygovernment.com/2012Issues.html The lesser of evils is still evil. Original Message Hi, I have a number

Re: [time-nuts] How to get unknown frequency quartz crystals oscillating

Mike, XTALs does work in air, or better: dry gases (i.e. nitrogen) too, but OK; quality exemplares are (for better, spurious free, oscillating) in vacuum... Karl Virenfrei. www.avast.com

Re: [time-nuts] HP 106a oscillator connectors question

Several have suggested that these are 10-32 connectors. If this is true, a 10-32 nut will thread on them with no trouble. I believe these **may** be the 1/4" diameter variant that was 93 ohm characteristic impedance. I **think* they are called an S-93. Still 32 tpi, but 1/4" in diameter. You

Re: [time-nuts] How to get unknown frequency quartz crystals oscillating

Tim wrote: The Pierce logic-gate-biased-active oscillator is pretty reliable to start and will oscillate somewhere with most crystals from kHz to MHz. As you found out, it will often come up on one of many overtones. To reduce chance of coming at an overtone, a series resistor from logic gate

Re: [time-nuts] How to get unknown frequency quartz crystals oscillating

Thanks all for your advice, hints, tips and links. Lots to read , do and some hardware to check. I don’t have a frequency generator so I’ll have to go another route. Oh. One last Q. Has anyone tried repairing the « spring » wire electric connections on large quartz plates. In one large unit

Re: [time-nuts] How to get unknown frequency quartz crystals oscillating

Tim Shoppa wrote: >The Pierce logic-gate-biased-active oscillator is pretty reliable to start and >will oscillate somewhere with most crystals from kHz to MHz. >As you found out, it will often come up on one of many overtones. >To reduce chance of coming at an overtone, a series resistor from

Re: [time-nuts] HP 106a oscillator connectors question

Corby wrote: Need help identifying the RF connectors on the unit. Corby, I may have some connectors on leads but would have to dig deep in my garage. They were used a lot on some UK made Racal receivers in the sixties... Let me know if you still need them. Dan

Re: [time-nuts] Mystery hp Ovens For Sale

Hi The “small” (less than a pound) 100 KHz crystals are not really great in terms of performance. If you get a GT (big thin square plate with attach right in the middle) they can have ok temperature performance. Because of their small size, their Q is relatively low and thus things like phase

Re: [time-nuts] How to get unknown frequency quartz crystals oscillating

With random old crystals in holders, it often helps to disassemble the holder and clean crystal and holder plates with alcohol (my favorite back in my youth was carbon tetracholoride but not so easy to find these days.) I'm guessing most of your round blanks were for FT-243 type holders. The

Re: [time-nuts] How to get unknown frequency quartz crystals oscillating

Hi Simple approach is to assume that you have a crystal resistance in the range of 100K ohms. If you guess to high, the oscillator will just work to well :) Multiple JFETS in cascade for the higher frequency stuff should work. For anything below 20 KHz, an op-amp is likely your best bet. A

Re: [time-nuts] How to get unknown frequency quartz crystals oscillating

A vector voltmeter can be replaced by a spectrum analyser or even a 14 bit scope with or without a preamp. In lieu of phase information one can measure the 3dB bandwidth to elicit the Q, combined with measurement of the low frequency shunt capacitance and the attenuation at resonance, the

Re: [time-nuts] How to get unknown frequency quartz crystals oscillating

Some idea of the crystal equivalent circuit at the oscillation frequency would help considerably. Usually lower frequency crystals have a considerably higher series resistance than those operated at 1MHz or above. At frequencies below 100kHz or so a Meacham bridge using something likke a

Re: [time-nuts] How to get unknown frequency quartz crystals oscillating

On reflection, building a jig to measure the crystal transmission as a function of frequency may be much easier than attempting to build an oscillator for an unknown crystal. However a suitable signal generator and detector are required. Once the crystal parameters are known its much easier to

Re: [time-nuts] How to get unknown frequency quartz crystals oscillating

On Sat, 4 Jun 2016 10:46:40 +0200 Mike Cook wrote: > If you had a crystal with unknown frequency and drive requirements > that you wanted to investigate. How would you go about it? I would use some signal generator to generate a tunable sinusoid and feed this to the quartz

Re: [time-nuts] HP 106a oscillator connectors question

Corby wrote: Need help identifying the RF connectors on the unit. Original MALCO connectors: Instruction sheet (note that these connectors require an installation tool):

Re: [time-nuts] Mystery hp Ovens For Sale

> Le 4 juin 2016 à 06:59, Ian Stirling a écrit : > > It looks like the quartz is in the sealed glass "valve", or "tube". > > I have removed a similar glass vacuum enclosed 100 kHz frequency > marker generator from my Eddystone EA12 receiver that I bought from > Tom Roberts,

[time-nuts] How to get unknown frequency quartz crystals oscillating

Hi, I have a number of crystals either in glass, bakelite, ceramic or metal housings that I would like to get resonating . They are of three basic types. Square, or rectangular flat Round flat Bar square section Sizes range from 2-10cm or more in the longest face. Some have frequency

Re: [time-nuts] Transformer inrush current and transformer simulation

Don't let the start of the simulation be the power on time. Best to set up the AC mains volts at zero volts for a half second then go up to 120 VAC. So you actually simulate the power switch. The time before the start of the run is not defined Also you should Google "spice transformer model"