[Orion] 3 PPM freq stability

[Henry Pfizenmayer]

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