A problem we have experienced on several field days is that transmitted RF from a transmitter overpowers a nearby receiver despite it being on a different HF band or even on a more distant part of the spectrum.

Band pass filters are the usual approach to solving such an issue.  However, another approach is to place a wide notch filter over the entire interfering transmission.  This is the approach described by John Crowder, G0GDU in this article passed to me by Rex G4RAE last Wednesday.

Andrew
G0RVM