The synthesizer HF module HFM-S is the forward-looking alternative to the quartz HF module HFM-4 for all ROYAL evo transmitters . Of particular interest to all those who often have to change channels. Transmitter crystals are no longer required. Channel selection is easy and convenient via software. The desired channel is set on the transmitter in a channel change menu. This does not change the transmission type (FMPPM) . All receivers can be used without restriction work with the conventional quartz HF module HFM-4. The HFM-S module can be retrofitted at any time. The transmitter automatically recognizes the module when switched on. A scanner module can be retrofitted as an option.