Thanks for the replies
@Rory, I seriously thought about it, but the sniffer circuit rectifying diode, SMT prob 0805 size, is quite close to the RF power device, an XRF 286, which is for good measure mounted on a large chunk of copper heat spreader about 2 inches square and 1cm thick, I think my ability to stuff it up while removing it would be pretty good.
@sarah, that's a good idea, I've used it before to generate a low current voltage supply greater than rail (positive), it meets my aim to keep it simple.
For interest the RF power amplifier is for Amateur radio and I am having a go at Moon-bounce, (communicating via moon RF reflection) round trip ~10^20dB loss
Transmit side uses an Icom 910H 1296MHz 10W out, into W6PQL splitter then two XRF286s with combiner, I should get 150W out. LDF450 coax.
Antenna VE4MA feedhorn, (return loss 17dB) circular polarisation, onto 3m satellite dish (steerable 150 degrees Azim, 80 degrees Elev)
Receive G4DDK design PHEMT pre-amp, 37dBgain 0.27dB noise factor, back into Icom 910H
Sequencing of relays, power supply by MiniKits sequencer.
Arduino; Current plan is for display of voltages (12 and 28v rails) and current draw, power out (via sniffer), later plan is to use the Arduino also to track the moon.
Again Thanks, Rob
PS photos of PA, looking down feedhorn and pre-amp