On 11/20/2011 8:45 PM, Don Wilhelm wrote: > This new ruling (when it takes effect) amplifies the cardinal rule - > "User, know your transceiver and how it handles both the transmit and > receive frequencies for all modes".
Yeppers, just like it's always been. > We hams use the SSB suppressed carrier frequency,, but (at > least for 60 meters), the FCC regs refer to the center channel frequency > - the suppressed carrier frequency is left for us to figure out. That's pretty standard on the planet, except for us. But then in our defense, no one "tunes around the band" like we do ... indeed, most can't "tune" at all. > NOW, I can't resolve why everyone uses a downward > shift of 1.5 kHz instead of a shift of 1.4 kHz - perhaps someone can > explain that difference to me. I suspect it comes from the fact that a single-channel analog audio radiotelephone baseband generally is considered to extend from 300 to about 2500 or so Hz, give or take a little on each end. So, in the rules, the FCC "helped us out," and told us where to put our suppressed carrier [what most of our radios show us] such that our RF signal will be more or less centered in the channel allocation after our transmitter processes the baseband. Or ... maybe not, but the math does work out :-) One big thing we ALL need to understand: As currently proposed, the new CW and digital modes are also to be centered. It says so, and in the discussion, the Commission explains why they did not accept the ARRL recommendation that the channel be treated as a 2.8 KHz "ham band" for PSK purposes. The good news: We started with 5 USB channels, NTIA agreed to swap one for another channel with less primary user activity, and to give us both CW and digital use. If we behave with this as we apparently have with USB-only, we might get more. 5 MHz is a really cool spectrum, quite different than 7 or 3.5 MHz, that's probably why the NTIA/FCC feel somewhat protective of it. 73, Fred K6DGW - Northern California Contest Club - CU in the 2012 Cal QSO Party 6-7 Oct 2012 - www.cqp.org ______________________________________________________________ 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
