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The AMSAT News Service is cautioning users of high duty
cycle digital modes – such as FT8 or MSK144 – to be very careful of power
levels used on transmissions made via satellites, as a high-power signal can
affect all other users of a satellite transponder. AMSAT suggests possibly
avoiding the use of these modes on satellites due to problems encountered by
other users.
The SSB/CW linear transponders on China's CAS-4A and
CAS-4B satellites were turned on in mid-October, according to the AMSAT News
Service. Uplink frequencies are 435.220 MHz for CAS-4A and 435.280 for CAS-4B.
Corresponding downlink frequencies are 145.870 and 145.925 MHz. Each has a
20-kHz passband.