On Wed, 2009-12-02 at 21:06 -0800, Alan Bloom wrote: > On Wed, 2009-12-02 at 18:36 -0800, [email protected] 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.
I just did a little Googling on the Internet (AC6V.com and elsewhere) and discovered to my astonishment that this is an actual bona-fide controversial subject among radio amateurs. Despite the fact that a simple 2-minute back-of-the-envelope calculation is all it takes to disprove the myth. For the record: Intermediate frequency: Carrier 9.000 MHz Sideband 9.001 MHz ==> USB Add 5 MHz VFO: Carrier 9.000 + 5.000 = 14.000 MHz Sideband 9.001 + 5.000 = 14.001 MHz ==> USB Subtract 5 MHz VFO: Carrier 9.000 - 5.000 = 4.000 MHz Sideband 9.001 - 5.000 = 4.001 MHz ==> USB I can't believe people are actually arguing about this! Al N1AL ______________________________________________________________ Elecraft mailing list Home: http://mailman.qth.net/mailman/listinfo/elecraft Help: http://mailman.qth.net/mmfaq.htm Post: mailto:[email protected] This list hosted by: http://www.qsl.net Please help support this email list: http://www.qsl.net/donate.html
