[Orion] 3 PPM freq stability

[Grant Youngman]

> One of my suggestions for a future Orion is to provide a TCXO 
> tweak adjustment in the menus.  That would let everybody get 
> down to +/- 1 ppm at least.  If you want to be really 
> elegant, provide  a zero beat tuning indicator (or beat 
> frequency counter) on the LCD screen.  Very little hardware required.

I agree with that idea.

Another way to deal with it, since everything is based on one master TCXO,
would be a firmware implementation akin to Carl's "Calibrate" procedure in
his software.   It seems as if it would be simple enough, but is more code
in the firmware block that generates the front panel frequency display.  Not
sure if that would exacerbate any already critical timing problems.

Pretty simple from a user perspective.  Zero beat 10 Mhz WWV, for example,
(sidetone is close enough), punch a "calibrate" function in the menus, and
have the radio compute the necessary display offsets.

We're probably overly an*l about 10-20 Hz errors in the displayed frequency
anyway. I tweaked my TXCO maybe a year ago, and got within a couple of Hz at
10 Mhz after warmup, but it's shifted a bit since then as the crystal has
aged, or the table's been bumped, or alien tachyon beams have affected the
thing, or whatever :-)

Grant/NQ5T