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[2E0ILY]

For reason or reasons unknown my antenna change over relay (home brew using Russian REW-15 high power co-axial relay) put 1 kW of RF up the RX antenna port of my TS-590, which as you can imagine, hasn't done it a power of good. I don't know if the relay flashed over or what. It does have a 500mS delay. I want to run and test it with the RX antenna socket of the change over relay box going to my dummy load, so if a TX session is sent to the RX antenna port the amp will survive. My question is what device could I put across the dummy load that would show if even a very brief period of RF went to the relay's RX port? Also, how can I measure the voltage the relay is having to switch given it's in the house before the matching and loading coils outdoors. I know that there will
be many kV at the antenna end of the loading coil, but at the output of the Class D FETamp (before the LPF bank) it should be fairly reasonable? Thanks.

[K8BYP]

"what device could I put across the dummy load that would show if even a very brief period of RF went to the relay's RX port?"

The "old solution" was, as was used in the Drake B lines, a small light bulb in the RX antenna line (I forget the number, a # 47 has the same filament). If over-voltage is applied, it will light up, go to high resistance and possibly blow open and effectively disconnect the RX antenna source.

A modern diode could be used from RX line to ground (or a pair). Diode(s) will add a small amount of capacitance to the RX antenna line, but that shouldnt be a problem.

Its critical especially in TR relays to have clean and properly timed contacts.

"Also, how can I measure the voltage the relay is having to switch given it's in the house before the matching and loading coils outdoors"

Calculate it from impedance and power level. V = (8PR) ^ 1/2 (P= power R = resistance of the feed at the relay contacts)

ALso realize that a transient fault in the antenna can send a large voltage spike back down the line.