[Elecraft] K4

[Dave Fugleberg]

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 <KY5G at montac.com> 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" <
> lists at subich.com> Date: 5/19/18  8:01 AM  (GMT-05:00) To:
> elecraft at mailman.qth.net Subject: Re: [Elecraft] K4
> > Ed,
> >
> >
>
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