This low pass filter board works well for the HF bands. It also has a notch filter to further reduce the 2nd harmonic.
This low pass filter board works well for the HF bands. It also has a notch filter to further reduce the 2nd harmonic.
This RF relay board is a simple transmitter/receiver relay board that switches the Antenna to either the Receiver or the Transmitter. The relay can be activated in several ways, including by an opto-isolated circuit.