The 4-70-54 notch filter installs quickly and easily via standard BNC bayonet couplings, in-line between radios and antenna. The 4-70-54 rejects in excess of 50dB of 1575.42 signal at the source. Each filter is individually tuned and checked to assure maximum performance.

An aircraft GPS receives its positional information at 1575.42 MHz while communications radios on-board typically broadcast in the 121.5 MHz range. The 4-70-54 filters the wide separation in frequency bandwidth and communications noise at the GPS frequency.