[TenTec] Orion 565 Oscillator frequency problem

[Martin Ewing AA6E]

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 at 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 at ewing.homedns.org
+1-203-315-5160