[TenTec] Corsair question

Dr. Gerald N. Johnson geraldj at weather.net
Sat Apr 16 12:14:19 PDT 2011


No Steve you are wrong. There is side band inversion. I was there.

Look at it this way. say you have a carrier at 9.000 and a tone at 
9.0015. Subtract 5.000 for 80 meters, the carrier comes out at 4.000 and 
the tone comes out at 3.9985, LSB. Add 5.000 for 20 meters, the carrier 
comes out at 14.000 and the tone at 14.0015, USB.

Its NOT folklore or myth, its the truth. AND IT IS THE REASON FOR THE 
SIDBAND CONVENTION we have today and that is fundamental to the Corsair 
and Corsair II normal sidebands because they use they same mixing 
schemes as did many Tentecs before them. In the OMNI VI they arranged 
all the LO injections to be on the highside, but CW to be only on LSB so 
it runs CW on LSB on all bands. With solid state switching some of the 
anomalies were taken out in the control logic that are not so easily 
changed in the Corsairs because mode switching is a ganged switch.

73, Jerry, K0CQ

On 4/16/2011 1:00 PM, Steve Hunt wrote:
> Jerry,
>
> I never understood that piece of Ham folklore, or should it be "Ham Myth" :)
>
> In a mixing arrangement comprising a 9MHz IF and a 5-5.5MHz LO, designed
> to cover 20m/75m, there is *NO* sideband inversion between the IF and
> the RF. A USB signal generated at the 9MHz IF would become a USB signal
> on 20m and also a *USB* signal on 80m.
>
> So, simplification of the sideband generation or detection for that
> simple mixing arrangement cannot be an explanation for the sideband
> convention we have today.
>
> 73,
> Steve G3TXQ
>
>


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