Comment Re: So you use Radio instead, eh? (Score 1) 48
True. The ping frequency is low though (hundreds of ms between pings) which limits the modulation sidelobes, and even the initial banging on of the carrier at the beginning of each ping is fairly well bandpass filtered by the high Q of the transmitter. You can't hear a tag click/chirp/whatever if you hold it against your ear.
But if seals can detect upwards of 180khz as you're saying... Yeah, that's a problem.