On 11/18/2025 12:53 PM, Jack Brindle via TowerTalk wrote:
To add to the info, assuming your 40 dB is correct, that would put a bit over
100 mW (62dBm - 40 dB = 22 dBm) into the receiver. The rx damage point is about
16.7 dBm. I would definitely not trust that setup, and even if there is no
damage, the rx would be completely blocked, precluding SO2R. Filters and
diplexer are needed...
Yes, but -- there are many ways to skin that cat. Like RX bandpass
filters. Look at what W6GJB and I managed in his contesting trailer.
k9yc.com/7QP.pdf
There are multiple components in the system that allow us to run two
K3/KPA500 stations on harmonically related bands with feedpoints within
a foot of each other. Leave out any one of them and it doesn't work. The
components are double stubs on the 80M and 40M antennas to kill
amplifier harmonics, serious chokes at the feedpoints of each antenna,
and W3NQN RX bandpass filters.
73, Jim K9YC
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