What you are seeing seems typical for the Orion. My N4PY Orion control
program has a calibrate feature in it that lets the program display correct
this frequency error. You tune in WWV at 10 mhz and, tune in the frequency
just as you have done and then click "calibrate". the program then figures
out the error at all frequencies and adds this correction to the program
displayed frequency. It's a lot easier than adjusting the TXCO which is
very touchy. See www.n4py.com
73,
Carl Moreschi N4PY
Franklinton, NC
----- Original Message -----
From: "Henry Pfizenmayer" <pfizenmayer@worldnet.att.net>
To: <orion@contesting.com>
Sent: Tuesday, May 17, 2005 3:34 AM
Subject: [Orion] 3 PPM freq stability
> Just curious from some of the Orion gurus - The past couple days I have
been
> watching the readout at 10 mhz on my Orion. It looks like it starts almost
> dead on cold , then slowly drifts down to about 27 cycles low over several
> hours - then wanders around about 2 or 3 cycles . I am not really trying
to
> pick fly specks out of the pepper but was curious what is going on , and
am
> somewhat inclined to re-set the TCXO to be on closer after a couple hours
> rather than at cold.
>
> Just for grins I checked 2.5 , 5, 10 , and 15 Mhz after it had been on a
> couple hours - and was a little surprised at what I see.
>
> 2.5 mhz 1 cycle low
> 5 mhz 9 cycles low
> 10 mhz 19 cycles low
> 15 mhz 29 cycles low.
>
> After about 10 hours , at 10 mhz it runs 23 to 26 hz low.
>
> I cannot tell from the manual what the synthesizer scheme is - but I was
> surprised that with a fixed IF the mixing scheme would be off as a strong
> function of rx freq. Would have thought the injection would have been
phase
> locked to be off the same amount on all bands. I would not think they have
> any conventional xtal oscillators for the offsets ?
>
> Is there any web site that shows the mixing scheme that I could look at ?
>
> I was watching the zero beat with WWV by using either LSB or USB (both are
> the same) , agc off any playing between atten and rf gain and antenna to
be
> able to hear the 1 hz or less beats . (Obviously using the sub receiver )
>
> Rgds- Hank K7HP
>
>
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