The program has a frequency calibration procedure. You run this procedure
at 10 mhz. Once the error at 10 mhz is determined, the error at all other
frequencies can be computed. When you run diversity mode with my program,
the Orion is not put into diversity mode. Instead, the program sends the
same frequency to both VFO's to control both receivers, but these
frequencies are adjusted to compensate for the error in the 2 receivers. So
the main receiver will get a correction for how much it is off in true
frequency, and the sub-receiver will get a slightly different correction to
match it to the main receiver. The display on the Orion will not exactly
match the program display, but the program display will be exact and the
radio display will differ by a few hertz depending on its error. The whole
trick is to perform the calibrate procedure very accurately.
Carl Moreschi N4PY
121 Little Bell Drive
Bell Mountain
Hays, NC 28635
----- Original Message -----
From: "Ken Brown" <ken.d.brown@hawaiiantel.net>
To: "N4PY" <n4py@arrl.net>; "Discussion of Ten-Tec Equipment"
<tentec@contesting.com>
Sent: Saturday, December 20, 2008 4:54 PM
Subject: Re: [TenTec] Lone voice in the wind
Hi Carl,
My N4PY Orion software has can be operated in diversity mode. And my
program has an adjustment in it to allow for a slight frequency offset in
the 2 receivers and correct it.
That sounds interesting. Can you explain how it works? I thought the
reason the two receivers are always off frequency by some small amount
is that they use different PLL schemes, with different minimum
resolution step sizes. How can software change that? Perhaps I've got it
all wrong.
Even with different step sizes, at some frequencies the two receivers
might be on exactly the same frequency. Maybe the N4PY software can be
operated so that only these particular frequencies can be tuned?
DE N6KB
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