Strong RF signals can interfere with wireless microphone reception, especially when an unwanted transmission overloads the receiver front end. This article introduces the idea of using specific lengths of coaxial cable as a simple notch filter.
The principle depends on wavelength, velocity factor, and the quarter-wave behaviour of an open-ended cable. A BNC T-piece and a correctly trimmed section of coax can reduce a problematic frequency while leaving the wanted frequency mostly intact.
This is not a replacement for high-end RF filtering, but it is a low-cost field technique that can help engineers understand and solve certain interference problems quickly.