As we all know, CQWW produces huge activity on all HF bands. This year I was
hearing stations up to well above 1850kHz. I have found that trying to run
Europe is often more productive in the 1840-1850 segment, presumably because it
is less crowded than lower in frequency.
Late in the contest I started to CQ on about 1842kHz, and after a while, and
several QSOs, was told (on CW): "Please QSY. 1840 is reserved for FT8. Good
luck in the contest." Ignoring the fact that nobody has a reserved frequency on
any band, I thought OK, don't want to upset anybody, and moved to 1842.9kHz.
Shortly, the same message arrived.
My (probably incorrect) understanding is that FT8 stations are using USB with a
carrier frequency of 1840kHz. So a CW station on 1842.9 should be out of their
passband. I did listen carefully and could not hear any FT8 transmissions above
1842.2. (I have multiple receive antennas in a very quiet location.)
I believe that FT8 transmissions in principle use a microscopic bandwidth, but
it appears they actually need a wide clear channel.
Yes? No?
73 Roger
VE3ZI
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