CHIRP Bands

CHIRP transducers are designed to work either in one single frequency band or in two frequency bands simultaneously. Single-band transducers are cheaper and are suitable for shallower water, for lake fishing and for specialized deep-water uses. Dual-band transducers are more popular for general saltwater fishing.

Sounders and fishfinders are designed to process signals from either single-band or dual-band transducers but rarely both. It is important that the type of transducer chosen matches the capabilities of the sounder.

Airmar has named three common frequency bands:

• Low Band : ~ 40-75 kHz
• Medium Band : ~ 80-130 kHz
• High Band : ~ 130-210 kHz

The actual frequency range used varies between transducers. Some higher-priced models have a lower 'Low' range to handle deep ocean fishing.

Dual-band transducers are usually either Low/Medium (LM) or Low/High (LH). For example, the B265C dual-band transducer is available as an LM model with frequency bands 42-65 kHz and 85-135 kHz, and as an LH model with bands 42-65 kHz and 130-210 kHz.