SDRplay Community Forum

Thank you Jon for the answer!

For 50 ohm unbalanced inputs there are several off-the-shelf products as well as DIY receipts available about how to protect the RX.

But how about the Hi-Z-input? I don't know any commercial products for that.

I have handled it like this: The GND is connected to a proper dedicated RF ground. My antenna is a high-impedance one (D-KAZ), fed to the port by using 450 ohms ladder line. From P-terminal i have fed two 1N41418 diodes (in opposite polarities) to GND. And the same with the N-terminal.

With that setup, I have run not more than 100W into a separate antenna about 30 meters apart, and so far not burned the RSP2.

It would be nice to know if SDRplay does have a suggestion for a good protection of Hi-Z.

73, Jukka

You can do what I did... MFJ-1708, plus a homebrew "cascading relay" box....

The "relay box" triggers the 1708 from the mic PTT, then triggers the PTT circuit on my transceiver. The 1708 has a user variable delay to keep it in transmit mode until the transceiver quits transmitting.

You could add a third relay to ground out your Hi-Z lines as well.