[time-nuts] Good GPSDO on eBay?

Bob Stewart bob at evoria.net
Sat Jul 9 23:06:12 EDT 2016

And when you build your own, you're still left with the issue of the oscillator.  In my experience, only about 2 out of 3 of the 34310-Ts I get from China are worth using.  If you buy them one at a time your odds aren't good.  OTOH, as your first oscillator, especially for HF use, noise and stability aren't quite as important as if you're multiplying up to microwaves.

But, as a starter GPSDO, probably anything is good.  Frequency accuracy, even if a fraction of a Hz off, is all you're looking for at first.  I bought one of Bert Zauhar's (VE2ZAZ) circuit boards and chips for my first one.  It was a good experience.  And when I was done, I had a GPSDO that was as good as most of what you find on ebay in the bargain basement, but at a much lower cost.  But then you need a case, and something to compare it to, and something even better, and then you're a time-nut.

But one thing to remember Richard, is that the time-nuts idea of accuracy is much different from what you may be used to.  For HF ham use,+/- 1Hz accuracy is a big deal.  In the time nuts community, phase accuracy to the nanosecond level (and even better, if possible!) is what's important.



      From: Dimitri.p <dimitri at dotp.com>
 To: Discussion of precise time and frequency measurement <time-nuts at febo.com>; time-nuts at febo.com 
 Sent: Saturday, July 9, 2016 9:14 PM
 Subject: Re: [time-nuts] Good GPSDO on eBay?
since you asked ...
Many thoughts, none of them good.
Recycled components sold for real money.
Too many "versions" to figure out "what you got".
If all you want is a frequency standard to turn it on and "forget it" 
spend a few extra bucks and get one with all new components from a 
domestic company.
Or if you want to have some fun put together one of your own.

At 04:40 PM 7/9/2016, Richard Mogford wrote:
>This looks like a good beginner's GPSDO on eBay: 172148560746
>"This is GPS Disciplined Clock made with trimble GPSDO Board.Full 
>tested by Agilent 53132A with US-012 option and Ex-ref from trimble 
>thunderbolt GPSDO."
>      The seller says it has a sine wave output and is accurate from
>      10e-11 to 10e-12.
>Any thoughts?
>time-nuts mailing list -- time-nuts at febo.com
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