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Re: [CQ-Contest] 40m "new" approach to staying in the band?

To: n2ic@arrl.net
Subject: Re: [CQ-Contest] 40m "new" approach to staying in the band?
From: Michael Tope <W4EF@dellroy.com>
Reply-to: W4EF@dellroy.com
Date: Thu, 05 Nov 2009 08:08:19 -0800
List-post: <cq-contest@contesting.com">mailto:cq-contest@contesting.com>
Steve London wrote:

>Not a bad idea, at all.
>
>Where did this business about high bands being USB, and low bands being LSB 
>come 
>from, anyway ?
>  
>
Just a guess, Steve, but I think it must have originated with 9MHz 1st 
IFs in the rigs of the era and the choice of 1st LO frequencies. High 
side mixes (RF=LO+IF) don't invert their spectrum whereas low-side mixes 
(RF=LO-IF) do invert their spectrum. Thus, the same 9MHz USB IF Filter, 
carrier oscillator, and balanced mixer would produce LSB when 
downconverted to 40 and 80 meters and USB when upconverted to 20, 15, 
and 10 meters.

73 Mike W4EF...................



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