Hello Joe and all,
.
We all have been missing JT65 mode sensitivity and proposed WSJT-X 2.0 new FT8
approach with 0.2 dB sensitivity penalty can make things even worse.
.
I would like to ask you to consider a new protocol where callsign hash would be
used instead of the real callsign in all messages but CQ and incoming call,
this way we can get back to -25..26dB SNR sensitivity although will get more
limited with the free message length.
.
CQ message: 28 bit callsign1 + i5bit + 12 bit CRC = 45 bit
incoming call: 10 bit call1 hash + 28 bit callsign2 + i5bit + 12bit CRC = 55 bit
report message: 10 bit call2 hash + 10 bit call1 hash + i5bit + (10 bit call3
hash for DXpedition) + 6 bit report + 12 bit CRC = 43(53) bit
roger+report message: 10 bit call1 hash + 10 bit call2 hash + 6 bit report+
i5bit + 12bit CRC = 43 bit
73 message: 10 bit call2 hash + 10 bit call1 hash + 15 bit GRID + i5bit +
12bit CRC = 55 bit
RR73 message: 10 bit call1 hash + 10 bit call2 hash + 15 bit GRID + i5bit +
12bit CRC= 52 bit
.
Spare bits can be used for nonstandard(special) callsign transmission in CQ
message. call1 hash could be omitted in the incoming call message if this
message is originated by the nonstandard(special) callsign.
.
Probably we can optimize protocol even better while a main idea is to transmit
a full callsign only once per each QSO and to transmit not more than one full
callsign in the message.
.
73 Igor UA3DJY
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