I also wish the oscillator could be replaced with an aftermarket unit, maybe
one like this:
http://www.greenrayindustries.com/library/yh1420.pdf
I don't know what those cost, but I would pay $200 to get better stability.
I know a lot of folks don't really care, but for ESSB, 10 Hz off frequency
starts to get noticeable. Besides, I just like being accurate!
Ron N6IE
www.N6IE.com
----- Original Message -----
From: "Martin Ewing AA6E" <aa6e@ewing.homedns.org>
To: "tentec-list" <tentec@contesting.com>
Sent: Tuesday, May 20, 2008 5:27 PM
Subject: Re: [TenTec] Orion 565 Oscillator frequency problem
Rob / Jim,
You could check my blog entries at
http://blog.aa6e.net/2005/08/orion-frequency-calibration.html and
http://blog.aa6e.net/2005/11/orion-recalibrated.html .
The TCXO can be tweaked with difficulty so that it comes to equilibrium
after warm-up a little closer to the correct frequency, but basically it
is a +/- 3 ppm unit, and you can't tweak it much better than 0.5 ppm or
so, and it won't stay set forever. Seasonal room temperature changes come
into play at that level in my shack.
Too bad the oscillator can't easily be replaced with a better one. You
need one that is custom made for 44.55 MHz.
73 Martin AA6E
K4CGY wrote:
Hi Rob,
Rig is within spec . Spec is ± 3 PPM which is 45 Hz @ 15Mhz
and 60 Hz @ 20 Mhz. You have a maximum drift of 32 Hz @ 15 Mhz
and 42 Hz at 20 Mhz. However the frequency starts off at 32 Hz
low so if the TCXO has a trimmer it likely can be touched up a
little to be closer.
73 Jim K4CGY
--- Rob Santello <K6DQ@drumon.com> wrote:
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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Martin Ewing, AA6E
aa6e@ewing.homedns.org
+1-203-315-5160
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