Rob:
The frequency drift problem on Orions and Orion II's is well documented.
Since every TCXO is slightly different, replacing the unit might improve
overall stability, but it might also make it worse. Adjusting the TCXO will
get it closer on frequency but it won't improve the drift problem.
If you go to my web site, www.n6ie.com, you see two pages that deal with the
problem. One is a simple mod that involves placing a small fan over the
TCXO to slow down its heat-up rate and allow the temperature compensation in
the oscillator module time do its job, which improves overall stability.
The other shows how to adjust the TCXO so that after a reasonable warm-up,
which is reduced to about 30 minutes with the fan mod, the frequency ends up
pretty close to WWV, generally within +- 3 Hz at 15 MHz.
Ron N6IE
www.N6IE.com
----- Original Message -----
From: "Rob Santello" <K6DQ@drumon.com>
To: <tentec@contesting.com>
Sent: Tuesday, May 20, 2008 12:04 AM
Subject: [TenTec] Orion 565 Oscillator frequency problem
> Hello group,
>
> I've lately noticed my Orion 565 is way off frequency and drifting
> during warm-up. These measurements were taken at 80 degree room
> temperature beating against WWV on both 15 and 20 MHz.
>
> Initial turn on:
> 15 MHz WWV: 14.999.968
> 20 MHz WWV: 19.999.956
>
> 45 Minutes into warm-up:
> 15 MHz WWV: 14.999.946
> 20 MHz WWV: 19.999.928
>
>
> 1hr 30 Minutes into warm-up:
> 15 MHz WWV: 14.999.939
> 20 MHz WWV: 19.999.919
>
> 3 hours into warm-up:
> 15 MHz WWV: 14.999.936
> 20 MHz WWV: 19.999.914
>
> So my questions are:
> 1. Does it look like the TCXO has a problem or might it be something else?
> 2. Will adjusting the oscillator fix the frequency problem and
> somehow positively affect the drifting as well?
> 3. If the TCXO is bad, can the TCXO be replace at home or do I need
> to send it to Ten-Tec (and hopefully get any needed updates too)
>
> Thanks for any help, suggestions and information.
> --rob--
> K6DQ
>
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