There is another potential problem if feeding two amps to two antennas that
are reasonably close: RF from one antenna is induced into the other antenna,
gets fed into the amp and causes some interference (mixing ?) that shows up
as a raspy signal.
Tried it, and heard it on another station attempting the same setup.
It seems that it would be easier to control the phasing at the input of the
PAs, but the above effect messes it up, unless antennas are widely separated
and they do not "feed" each other setup.
So, it appears that it is better to use one bigger amp and use proper
phasing to feed the two or more antennas.

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Yuri Blanarovich, K3BU, VE3BMV