There are indeed some bad/naive operators out there who either
don't know or care about the ways amateurs share frequencies, or
don't understand the wsjt-x UI and customs well enough to apply
them to FT8/FT4. However, avoiding interfering with each other
is hard, and a little charity is in order.
For example, propagation issues make it very difficult to avoid
transmitting on someone else's transmit frequency. On HF we have
the skip zone and at VHV/UHF interfering stations may not be in
line of sight of each other. Two examples:
I was operating from California on 20M in a RTTY contest and
heard two stations in the eastern US calling CQ on the same
frequency. I didn't even have to change tuning to decode both of
them. They must of been using automatic CQ systems, because they
continued on the same frequency for several minutes, almost like
the odd and even phases of FT8. My conclusion was that they were
in each other's skip zone. I managed to work both of them, so it
is unlikely they were intefering with my signal.
Our county ARES/RACES group has a set of 4 linked BBS systems
using 1200 bps modems and the AX.25 protocol on 2M. Congestion
control is by having each station wanting to transmit listen for
other stations, and then wait until the other station has
stopped transmitting before it transmits. During a county-wide
exercise, the county Emergency Operations Center (EOC) system
was unable to access its BBS because its antenna location kept
it from being heard by other stations. Not hearing the EOC
station, the other stations transmitted preventing it from
downloading its messages.
The fixed time slots of FT8/FT4 make it hard to find out if
there is another station on the same frequency as you, even if
propagation would let you hear it. It is one of the worst
features of these protocols. One way I try to address the
problem is to press "Halt TX", look at the waterfall, and then
press "Enable TX" to resume the transmission. If I do this fast
enough, sometimes my QSO partner can still decode my
transmission, just as if there were a few seconds of QSB.
It would be nice if wsjt-x could be setup to briefly halt
transmission at random times during a transmit cycle, listen,
and determine if there is another station transmitting in the
transmit frequency, and then resume transmission.
Another feature that might be useful would be to have wsjt-x
show frequencies where it is unable to decode any signals, as
they might be good transmit frequencies.
73 Bill AE6JV
-----------------------------------------------------------------------
Bill Frantz | "The only thing we have to | Periwinkle
(408)356-8506 | fear is fear itself." - FDR | 16345
Englewood Ave
www.pwpconsult.com | Inaugural address, 3/4/1933 | Los Gatos,
CA 95032
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