On Dec 3, 2009, at 9:25 AM, Ralph Parker wrote: > For all you young whipper-snappers with two letter calls who don't believe it: > 9 Mc. SSB mixed +/- with a 5 Mc. VFO did indeed result in opposite sidebands. > I was there.
No a 9 MHz IF will not swap sidebands. But, as N1AL has mentioned, a 5 MHz IF with 9 MHz VFO will swap sidebands. I didn't want to clutter the reflector since I thought Al has settled it, but to put another nail in the coffin, here was my email to Al last night: > You are right of course, Al. > > In the 9 MHz IF case, a superhet gives f(IF) = f(RF) + f(LO) for both 20m and > 80m. It is the sign of f(LO) that changes with the band. > > Thus, df(IF)/df(RF) = 1 for both 20m and 80m. > > In the 5 MHz IF case, it is f(IF) = f(RF) - f(LO) for 20m, but it is f(IF) = > f(LO) - f(RF) for 80m. df(IF)/df(RF) = 1 for 20, but it is -1 for 80m. the df(IF)/df(RF) are just partial derivatives. If the value is +1, USB in RF results in USB in IF. If it is -1, USB in RF results in LSB in IF. 73, Chen, W7AY ______________________________________________________________ Elecraft mailing list Home: http://mailman.qth.net/mailman/listinfo/elecraft Help: http://mailman.qth.net/mmfaq.htm Post: mailto:Elecraft@mailman.qth.net This list hosted by: http://www.qsl.net Please help support this email list: http://www.qsl.net/donate.html
