On the Effects of Receiver Bandwidth on the Performance of Avalanche Beacons

Contrary to transmitter frequency tolerance, the receiver bandwidth is not standardized for avalanche beacons. Some transmitters even transmit outside the specified tolerance range. This may give raise to compatibility problems. If the receiver bandwidth is widened to accommodate even out-of-band transmitters, receiver performance will be degraded. If the receiver bandwidth is made too narrow, this causes unpleasant audible effects and renders proper digital signal evaluation impossible. Simulation results for various settings are presented in audible and display format. They indicate that the optimum bandwidth for achieving long range is less than what would be required for good performance against transmitters that operate at the limits of the frequency tolerance. This can be mitigated by making the receiver adaptive to the transmitter's frequency. Receiver bandwidth should be optimized for best performance in terms of range. Out-of-spec transmitters should be replaced.