I'd guess they were monitoring every signal from radio bands that have a line-of-sight or one-bounce range limitations, as they could get the rest of the spectr

I'd guess they were monitoring every signal from radio bands that have a line-of-sight or one-bounce range limitations, as they could get the rest of the spectrum from their ground-based antennas. They're experts in signals intelligence and have no practical budget limitations. They're recording everything, automatically processing to find the interesting bits, and assigning real life humans to look at those interesting bits. I'm guessing that in the NYC area, at the very least Russia, China, and Canada are sucking up the same EM signals, or trying to. We mere mortals tend to assume that such a tool would be used for one thing in particular, because don't have cults of patriotism or bottomless bank accounts.