Grant,
You are correct about what you say. But common sense would say that if they
didn't want the tuner in the receive path, they would have just put the
tuner in series with the transmit low pass filters. This would have saved a
relay. I don't have the internal tuner to prove it one way or the other but
the following quote from Duane indicates the tuner in definitely in the
receive circuit.
"I've discovered this several times when I forget I'm in "split" mode and
VFO-B is on another band. After tuning, my RX is very attenuated! Oops!
So, it has helped me find a problem before I QRM'ed another band with my
calls. BTW, for the other responder, on the Orion, you must explicitly
initiate a "Tune" cycle. Merely transmitting does not do it for you."
So an easy test is to tune the tuner on a band such as 10 meters, and then
listen on another band without tuning. After determining relative strength
of some signals, then tune the tuner and see if things pick up.
73,
Carl Moreschi N4PY
121 Little Bell Drive
Bell Mountain
Hays, NC 28635
----- Original Message -----
From: "Grant Youngman" <nq5t@comcast.net>
To: "'Discussion of Ten-Tec Equipment'" <tentec@contesting.com>
Sent: Friday, March 31, 2006 5:53 PM
Subject: Re: [TenTec] Orion II AT tuner question
> > goes to the radio antenna switching logic. The end result is
> > the internal tuner is used on both the transmit and receive
> > path but only for antenna 1.
>
> That is what is shown in the schematics, but there is no schematic of the
> tuner board, which may have a shorting relay that is only opened on
> transmit.
>
> Regardless, there is no substantive difference in MDS with the tuner in or
> out of the circuit, regardless of where the tuner was last set. Which
means
> that there wouldn't appear to be a need to transmit into the tuner to
reset
> it every time you changed bands, as far as receive capability is concerned
> -- and that is my experience. And also would indicate to me that on
> receive, the tuner is effectively not part of the signal path.
>
> Without a tuner schematic, we're feeling the side of the elephant again.
If
> someone knows for sure, it would help, but it has no effect on receive
MDS.
>
> Grant/NQ5T
>
>
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