[600MRG] TX RF protection for RX antenna

[Paul N1BUG FN55mf]

OK, here is one I could use some help with.

I am using a large K9AY loop (twice the 160/80m size) for receiving on
MF and LF. It's the best of any antenna tried so far.

The problem is that LF, MF and even HF RF can get into it in sufficient
quantity to burn the 3 watt termination resistor and damage the
transformer! How can I protect the loop components from damage?

Using a relay to disconnect or short something is not an option. I
cannot run control cable to the loop. Coax is already used for the
voltage to switch directions on the loop.

What do you suggest I should use to shunt the RF from both sides of the
loop to ground so components won't get damaged? My first thought was
diodes (I'm old school) but I'm not sure small ones eg. 1N4148 can
handle the few watts of RF power and big ones appear to have too much
capacitance.

Of course I also need to protect my delicate SDR receiver, that's
another whole can of worms. At least for now I can try to remember to
always disconnect it before transmitting.

73,
Paul N1BUG