I had the same problem with different transmitters in the same location. So extraneous source of IR light or, as far as I can establish, of RF interference. And, as I said, the action of rubbing the exterior plastic of the Powermid will turn off the LED.

I was hoping for some tweak to the circuit that would make it less sensitive to whatever is triggering the TX mode.

Thanks for all the contributions.

Regards,

Roy