Clay, the individual signal with many of these digital modes modes is actually quite narrow, on the order of tens of hertz. It's just that by convention, everybody uses one SSB frequency for a given mode (such as FT-8 on 14.074). That means there may be dozens of QSOs going on in the equivalent bandwidth of one SSB conversation. The computer decodes all the signals in the receiver passband all at once, but you need to pick a spot within that bandwidth to place your transmit signal. Obviously if you pick a spot outside the transmitter's audio band pass, things won't work too well. That's not really an issue with FT8 if the software is properly configured, as it will automatically shift the VFO slightly on transmit to keep your chosen transmit audio frequency in the sweet spot of the transmitter audio bandpass. Fortunately, this tends to keep all that FT8 activity within about a 4 kHz slice of the band, so the rest of us can easily avoid it if we choose to. On Sat, May 19, 2018 at 10:00 PM Clay Autery <[email protected]> wrote:
> Mmmmm..... ESSB can transmit with right at 4 kHz bandwidth... > > I can't imagine that something can't be done in firmware to make it > possible in a digital mode.... > > WHY are they allowing digital modes to have such a huge bandwidth? > Seems counter-intuitive to me, but I am not a digital guy. > > 73, > > ______________________ > Clay Autery, KY5G > (318) 518-1389 > > On 05/19/18 07:07, Ed W0YK wrote: > > That's fine for decode, but transmit uses the 2.8 kHz filter. > > 73,Ed W0YK > > -------- Original message --------From: "Joe Subich, W4TV" < > [email protected]> Date: 5/19/18 8:01 AM (GMT-05:00) To: > [email protected] Subject: Re: [Elecraft] K4 > > Ed, > > > > > > ______________________________________________________________ > 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 > Message delivered to [email protected] ______________________________________________________________ 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 Message delivered to [email protected]
