> Assuming it is not just in the receive line, a bandpass filter may help
> you keep peace with any neighbors who are on the same band and others in
> the contest - as it will cut down on any extra "crud" your transmitter
> produces. It even works with "clean" transmitters.
>
A traditional bandpass filter does nothing for same-band overload or
interference, because by definition it passes the entire band.
The exception would be crystal or other very high Q narrow bandwidth
filters, but they are generally unsuitable for transmitting or very
expensive. I've experimented with high-Q filters on 160 meters, to allow
duplex operation on 160 with two radios at the same time, and it is a very
difficult filter to build. It would be much worse for something like 40
meters.
A bandpass filter will help clean up stuff outside of the band it is
designed for. This can make it safer to have a receiver running on one radio
through a bandpass (say on 40 meters with a 40 bandpass filter), while
transmitting on another radio on a different band (say 80m or 20M).
If a transmitter needs a bandpass, it might be time for an upgrade or
repair, or more antenna spacing. :-) Usually the receiver is the big worry.
73 Tom
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