Dave Platt wrote:
In article ,
Michael Coslo wrote:

I think that on some bands, such as 20 meters, a person can accidentally
stomp on another due to propagation, So often we only hear (or see) one
side of the QSO. We fire up, and soon the Ham we can hear and can hear
us tells us of our error.

That can happen on any HF band, I believe.

True, I used 20 meters as an example because it is the most common band
with the "worst" problem.


This issue was behind a lot of the protest over one aspect of the
ARRL's now-withdrawn "sub-bands by bandwidth" proposal. The proposal
had suggested opening up a much larger portion of the band to
unattended and semi-attended digital stations (typically, email
servers). Such systems are rather notorious for "stepping on" QSOs in
progress, due in part to this "only can hear one half of the existing
QSO" problem.

Many is the time that those robot stations have obliterated the PSK-31
segment of 20 meters. Two of them close the band. They don't check, they
just start transmitting, and they keep it up, presumably until they get
acknowledgment from another robot station.

It got so bad that Digipan added a decoder for the mode (no transmit) so
that we gould catch the callsigns, record the disruption, and and turn
them in to the FCC. Apparently this worked, because the problem is
diminishing.

- 73 de Mike N3LI -