BOS-Funk Tetra Kanalumrechner is a calculator app designed for bad radio communication. With this app, users can input the BOS-channel number and the corresponding frequencies will be calculated. The app also provides support for the new TETRA radio system.

In the case of "Intercom (duplex)" radio traffic, each channel has two frequencies: one in the upper band (transmitted by the relay station) and one in the lower band (transmitted by the mobile subscriber). Radios equipped with a duplex switch allow for simultaneous transmission and reception, as both parties use their own frequencies. It's worth noting that a control station connected to the relay station via a radio link may interrupt the mobile subscriber, as it has a priority circuit.

This app is a helpful tool for those working with bad radio communication systems, providing a quick and easy way to calculate frequencies for BOS channels. With its support for the new TETRA radio system, users can stay up to date with the latest technology in the field.