[time-nuts] Re: GPSDO replacement recommendation

[Attila Kinali]

Moin,

Thanks everyone who answered. All your suggestions have been noted!

I'd like to pick a few points out and comment on them, partially to explain
a bit what I'm doing and partially to give feedback to the group in general.

On Sun, 14 Apr 2024 09:53:33 -0400
Bob Camp via time-nuts <time-nuts at lists.febo.com> wrote:

> If cost is no object, there are lots of crazy choices.  Each of them has 
> it's own unique advantages and (usually) unique issues. 

If cost was no object, I'd go for a PolaRx5TR. But alas, I do not have
the small change to afford one of these. But I would definitely not say
no if someone at Septentrio would let me "borrow" one :-)

Yes, this is only a home lab (ok, a little bit more as I'm using it
for my scientific work as well, as my curent employer is very
very stingy when it comes to spending money on their scientists),
which means that I'm not going to spend thousands of euros on a nice
clock from Septentrio, Meinberg or SRS, even though I would like to.

On Sun, 14 Apr 2024 09:51:05 -0400
"David G. McGaw via time-nuts" <time-nuts at lists.febo.com> wrote:

> You might check the OCXO.  I recently repaired a Symmetricom UCCM that 
> the oscillator had died.  There are replacements available on-line and 
> there are footprints on the PCB to accommodate various versions.  The 
> only gotcha on the Symmetricom version was that it uses an oscillator 
> with 12V supply and 5V oscillators did not work. Had to replace with 
> same.  The others, Trimble and Samsung, use more generic 5V oscillators.

It's my second Trimble UCCM that died. And I guess it's the same failure
again: A dead reference in the OCXO. I could probably sit down and
get it working again. But I saw this as an opportunity to see whether
I can get something more up-to-date than an UCCM.

On Mon, 15 Apr 2024 19:07:03 +0100
David Taylor via time-nuts <time-nuts at lists.febo.com> wrote:

> Leo Bodnar has a 1 Hz to 1.6 GHz unit:
> 
> The unit now has firmware allowing operation up to 1.6 GHz, even though the 
> data sheet says 1.1 GHz.
> 
> Not an expensive unit, and very versatile.

I looked at Leo's original design many years ago. I was not thrilled at what
I saw. While the design per se is ok for what it is intended: a cheap, kind
of accurate frequency source for the hobbyist who needs to calibrate his
3-digit counter or to set his kitchen clock. But it is no good for what
a time-nut needs. We have had many DIY designs coming through this list
that were much better fits for time-nuts. I'm quite fond of the very simple,
yet astonishingly performant design of Nick Sayer a couple of years ago.
And one cannot beat Lars Valenius' design for simplicity.

Overall, what I found on ebay & co doesn't look very enticing at the moment.
The prices are astonishingly high. Most GPSDO go for higher prices than
rubidium clocks would go for just 5 years ago. I'm not sure I want to pay
that much for a GPSDO of questionable origin.


			Attila Kinali

-- 
In science if you know what you are doing you should not be doing it.
In engineering if you do not know what you are doing you should not be doing it.
        -- Richard W. Hamming, The Art of Doing Science and Engineering