Question: How much interference do the radio telescopes receive from EME propagation (Earth-Moon-Earth), and is it really a problem? I know that with just Amateur Radio levels EME contacts happen with just a few hundred watts, if not less, and can be received with around +35 dB gain with beam antennas and mast mount preamps. Therefore, I would just have to think that with the amount of gain that the Green Bank antennas have there’s got to be quite a bit of man made RF noise coming back to Earth via Moon reflection. THANKS!!! — Phil
Answer: Yes, radio observatories can detect EME RFI. This was recently demonstrated by the Murchison Widefield Array (MWA) when it observed FM-band radio signals reflected from the Moon. Note, though, that this was an experiment which was purposely looking at the Moon (for calibration purposes). In general, RFI reflected from the Moon is significantly weaker, and thus less of a problem for radio observatories, than locally-generated RFI.