Define intermodulation and its impact on receiver performance in dense RF environments.

• A. Intermodulation products are extra frequencies produced by nonlinear mixing of multiple signals; cause spurious responses and receiver desense
• B. Intermodulation improves signal clarity
• C. Intermodulation only occurs in transmitters
• D. Intermodulation is a type of antenna alignment technique

Answer: (A)

Intermodulation happens when multiple RF signals interact in a nonlinear part of the radio chain, such as a mixer or a high-level amplifier in the receiver front end. That nonlinearity creates new frequencies that are combinations of the originals (sums and differences), which are called intermodulation products. In dense RF environments, many strong signals can generate these products at levels that land inside the receiver’s passband or nearby, producing spurious responses and raising the noise floor. The result is desense, meaning the receiver becomes less able to hear weak signals, and false or misleading tones can appear as if they were real transmissions. This is why it’s a problem for the PRC-160 and PRC-163, where multiple strong signals in close proximity can compromise reception. It’s not about improving clarity, it doesn’t pertain only to transmitters, and it isn’t an antenna alignment technique.