Thanks for the reply! I'm quite interested in this. > FWIW, your "Hundreds of Milliwatts" are routinely used by hams to communicate world wide. Read again, I'

Thanks for the reply! I'm quite interested in this. > FWIW, your "Hundreds of Milliwatts" are routinely used by hams to communicate world wide. Read again, I've written "hundreds of microwatts" :) And that's for a reasonably wideband signal! A narrowband signal with high power has a lot more potential to interfere with a specific application. I seriously doubt anything of that order specially with a rough bandpass (passive) filter around the frequency of interest can cause significant interference. Passive filters have <1 gain, so they shouldn't risk narrowband amplification of the weak signal. The background noise should be within this order of magnitude, no? (I don't quite have the time to give numbers right now, but here's a source from quick googling: https://ieeexplore.ieee.org/stamp/stamp.jsp?arnumber=7833115 https://ieeexplore.ieee.org/stamp/stamp.jsp?arnumber=7833115 -- the ambient noise should be on the other of .1 uW / GHz; at a few hundred meters away this competes with our wideband microwatt-scale transmitter?) I'll see if I can do some actual calculations later