[Test-Equipment] Austron Model 1250A

[J. Forster]

Alan Melia wrote:

> Hi, I have just acquired an Austron 1250A frequency standard. This seems to
> work but the performance is a little disappointing, it seems to have a short
> term "wobble". Can anyone help with a copy of the specification so I have an
> idea of what I am testing against.

Google yields:

http://www.leapsecond.com/museum/au1250a/specs.htm

> Better still is there a service manual
> available, I havent seen it listed on any of my favourite sites.
>
> The "wobble" is a "backwards and forwards movement" compared with an LF
> off-air standard and 5MHz output has a pk-pk amplitude of about 90degrees
> over about 10 seconds. Watching it on a scope suggests that there are two
> source of instability that may be "beating together"...double oven ??. At
> the moment I suspect the oven control. I have several other OCXO reference
> instruments that do not display this "feature"...Racal, HP, Adret...

In my experience it's common for a local xtal oscillator to display jitter
against a LF (60 KHz) station. Some days it's worse, some days better. The LF or
Loran is only used for long a term frequency reference.

-John

>
>
> Thanks and Cheers de Alan G3NYK
> alan.melia at btinternet.com