Sorry, I was confusing the two, you did say *Sideband* 9.001 after all. So in the case where the IF is 5 MHz and the VFO is 9 MHz, we have:
Subtract 5 MHz IF: VFO 9.000 - 5.000 = 4.000 MHz VFO 9.000 - Sideband 5.001 = 3.999 MHz ==> LSB where we do see the inversion of the sideband. Bob NW8L On Thu, Dec 3, 2009 at 11:34 AM, Alan Bloom <[email protected]> wrote: > 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 <[email protected]> wrote: >> > 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 >> > >> ______________________________________________________________ >> 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 > > > ______________________________________________________________ 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
