No, we're talking about sideband direction, not VFO tuning direction. Al
On Thu, 2009-12-03 at 08:15 -0700, Bob Cunnings wrote: > Er, hold on. you write: > > > Subtract 5 MHz VFO: > > Carrier 9.000 - 5.000 = 4.000 MHz > > Sideband 9.001 - 5.000 = 4.001 MHz > > ==> USB > > but shouldn't it be: > > Subtract 5 MHz VFO: > Carrier 9.000 - 5.000 = 4.000 MHz > Sideband 9.000 - 5.001 = 3.999 MHz > ==> LSB > > Since we changing the VFO, not the IF freq? > > Bob NW8L > > On Wed, Dec 2, 2009 at 10:39 PM, Alan Bloom <n...@cds1.net> wrote: > > On Wed, 2009-12-02 at 21:06 -0800, Alan Bloom wrote: > >> 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. > > > > 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:Elecraft@mailman.qth.net > > > > This list hosted by: http://www.qsl.net > > Please help support this email list: http://www.qsl.net/donate.html > > > ______________________________________________________________ > 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 ______________________________________________________________ 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
