[time-nuts] AN/URQ-10A

[Tom Van Baak]

Roy,

In the early days of time-nuts and eBay the URQ-10A (made by FEI) was 
highly sought after due to its reputation for superb stability. There's 
also the -23A which is similar but has a frequency drift compensation 
feature.

With any old piece of gear it's hard to know if a specific unit for sale 
is bad, good, or superb so YMMV.

See fellow time nut Brooke's page with photos:

https://www.prc68.com/I/URQ10-URQ23.shtml

Is your -10A manual hard-copy or PDF? If the latter, consider adding it 
to fellow time nut Didier's page:

http://www.ko4bb.com/getsimple/index.php?id=manuals

I don't have any suggestions about fixing the ~10 Hz offset. It's either 
aged very far over the decades or perhaps there's just an oven problem. 
You can do some simple non-destructive experiments to determine which.

Note that some people would pay a lot for a ultra high stability 
oscillator with a 5 MHz + 10 Hz offset: it could make a wonderful beat 
note reference for a mixer-based frequency stability analyzer.

/tvb


On 7/17/2019 3:07 PM, Roy Thistle wrote:
> Hi All:
>
> I tried to search for this, in the forum, but, I didn't find much.
>
> I'm interested in getting a AN/URQ-10A... I have the manual. It's an old on ship, frequency standard.
>
> Does anyone have recommendations, or issues, concerning these units?
>
> The one I am thinking of is a little bit high (about +10 Hz, I think) and can't be "tuned" back to 5 MHz, without... I am guessing calibration. But, I am wondering if... because of the positive drift, if the crystal is damaged.
>
> By the way, how and why 5MHz... because its not that useful! … at least today.
>
> Does a frequency doubler… assuming a lock on the standard... cause errors in the 10 MHz signal obtained?
>
> Best regards and wishes
>
> Roy
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