I used to have a Corsair. I could never understand why I had to operate it
in the SBR (sideband-reverse) mode switch position to get the proper
sideband for 17 meters. All the other bands were O.K. with the SBN
(sideband-normal) position. Maybe this explains it.
73, Winston K4CWQ
----- Original Message -----
From: "Dr. Gerald N. Johnson, electrical engineer" <geraldj@isunet.net>
To: <tentec@contesting.com>
Sent: Sunday, August 17, 2003 10:26 AM
Subject: Re: [TenTec] Omni C on 17m
> No, Clark, the first IF of the Corsair is NOT 6.3 MHz. That's only the
> Bandpass Tuning IF of the RECEIVE IF. The transmit IF is still at 9 MHz
> as is the first receiver IF and the product detector. The cure for 17m
> is that the Local Oscillator mixing is on the high side (27 MHz) instead
> of the low side (9 MHz) which puts the standard sideband on Lower
> instead of the use standard of Upper. But the spur is gone because its
> from the LO not the IF signal.
>
> The LO second harmonic comes out of the mixer nearly as strong as the
> desired mixing product. That's what makes the spur.
>
> 73, Jerry, K0CQ
>
> --
> Entire content copyright Dr. Gerald N. Johnson, electrical engineer.
> Reproduction by permission only.
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