RE: Synthesized Tx’s what’s available how do they work?
The Polk TX uses programming to change the channel. The channel is stored with the model # memory.
When turning it on the sceen displays both frequency and channel number while the built-in scanner checks to make sure that channel is not busy. If the channel is being used the radio beeps and displays a bar meter showing the strength of the signal/interferance.
If the channel is clear it then starts to transmit and the screen displays the model # and the channel number.