Rob Sherwood NC0B agreed to freely share his full transmitted
composite noise measurements (dBc/Hz). Rob's measurements are
limited to only transceivers he has access to. He'll be pleased to
measure the performance of any transceiver, but of course he needs
access for testing.
Transmitted composite noise is only an issue in your immediate local
area -- such as interference to other hams within several miles if you
want to keep them as friends -- or to other transceivers in your own
station for SO2R, multi-op or Field Day. Transmitted noise can be
controlled by transmitter bandpass filters to reduce noise into
transceivers on other bands but a bandpass filter can't reduce noise
into a transceiver on the same band such as a CW and an SSB station
on the same band during Field Day.
Several hams asked about degraded transmitted noise power
when the output power is reduced to drive a modern amplifier.
Rob shared his data -- attached to this email -- for all of transceivers
he has tested for transmitted composite noise at 30 watts output.
Transmitted noise output from some transceivers -- such as the IC-7300 --
is much worse at reduced output power, most others are degraded
from 3 to 6 dB.
K3S transmitted noise with 30 watts output power is increased by
9 dB at 10 kHz from the transmitter frequency, but noise power
100 kHz from the transmitting frequency is degraded only 3 dB,
the minimum degradation one would ever expect.
The top of the first page is Rob's transmitted composite noise
measurements at 100 watts output power.
The bottom of the first page is composite noise measurements
at 30 watts output power.
The second page is six meter tests on the the TS-890S
73
Frank
W3LPL
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