Fred McKenzie wrote:
I agree that you are not likely to damage a radio. The common duplexer
(or triplexer) is often used to connect a single multi-band antenna to
multiple connectors of a multi-band radio, which is essentially multiple
radios in a single package. The difference between this and what you
are planning, is that the multi-band radio is usually not used for
simultaneous reception and transmission. Or at least you would accept
some desensitization if it occurred.

You can choose frequencies such that the third harmonic of the Two Meter
frequency is not in the IF passband of the 440 receiver, but you are
likely have overloading of the receiver's broad front end. (You may
also have some overloading of the Two Meter radio due to the amount of
power involved.)

I have heard this "armchair theorist" story many times, but I have
never experienced this problem with my 3-band Diamond and matching
triplexer. Sure I hear the harmonics full-scale when tuned that way,
but never any overloading let alone damage.

Maybe it is only a problem when using QRO.


I think it is more warranted to warn against collinear antennas that get
shipped in two parts. The connection is the weak point in the antenna.
Unfortunately it appears that for a 6/2/70 tribander it is the only
option. Normally they fail within a couple of years. Also on the high
bands there is severe fading in windy conditions because the entire
antenna bends too much.

My 2/70/23 tribander is in one piece and it does not have those defects.