[time-nuts] Re: GPSDO replacement recommendation

[Bob Camp]

Hi

I think that there are a lot of us looking for a “really good deal” on a PolaRx5TR :) :) :)

Bob

> On Apr 17, 2024, at 12:37 PM, Attila Kinali via time-nuts <time-nuts at lists.febo.com> wrote:
> 
> 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
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