On Wed, 2009-12-02 at 18:36 -0800, wb6r...@mac.com wrote: > LSB on the lower bands and USB on the higher bands is an artifact of > the mixing scheme, from the early days of SSB, of a 9 Mc IF mixed with > a 5.0 - 5.5 Mc VFO. (Yes, it was Mc in those days, not MHz.) Add and > you get 20m. Subtract and you get 80m. The subtraction results in > sideband reversal and so LSB became the "standard" for 80m. There is > really no reason now to not to just operate USB on all bands other > than tradition.
I've heard people say that many times over the years but clearly it's not true. A 9 MHz IF set up for (let's say) USB will still be USB no matter whether you add or subtract the 5-5.5 MHz VFO. What DOES result in opposite sidebands is to swap the IF and VFO frequencies, that is, using an IF in the 5 MHz range and a VFO in the 9 MHz range to get 80 and 20 meters without having to band-switch the VFO. I believe some early SSB rigs used that scheme, so that may be the origin of the current standard. Al N1AL ______________________________________________________________ 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
