Bernard ZL2BD gave a talk on how to safely switch between RX and TX antennas on your rig and demonstrated the circuit (which is probably not suitable for break-in keying). This circuit would allow us to use our active antenna or mag loop antenna on RX and our standard antenna on TX. The MFJ unit above is an alternative approach.
He also demonstrated a simple phasing circuit that works with two RX antennas to reduce noise levels or to peak a signal. Steering of a two antenna array throughout 360 degree is possible. Two active antennas can be used, or in fact, any two antennas spaced less than 1/4 wavelength apart can be steered (on RX) to reduce unwanted noise and maximise forward gain.
The following articles relate to the workshop:
