It puts the frequency in the bucket or it gets the sigterm again

From the moment I understood the weakness of my analytical math, it disgusted me. I craved the strength and certainty of numerical methods. I aspired to the purity of the Blessed Statistics. Your kind cling to your transforms, as though they will not decay and fail you.

Frequencies
- Came to comments just to look for this

I went on a Bat Walk last week. It was a few of us, walking around the park a little after sunset, pointing our radios at rotted trees and tuning it to frequencies of 45-65Khz. You could hear the bats with their popping sounds before you saw them, tiny things snatching up insects off the surface of the water... incredible maneuverability
The park ranger had this USB sonar device hanging off his phone, which scanned the entire frequency range in fixed bins of about 5Khz or so to produce a living heatmap, and used it to identify the types of bats that we were hearing and just about seeing: Common and Soprano Pippistrellas, and some Noctules.
(src: https://www.researchgate.net/figure/Peak-frequency-and-signal-duration-for-eight-bat-species-emitting-QCF-quasi-CF-pulses_tbl1_313207046)
It was just a group of us, huddled in silence listening to the crackle and pops of these little guys feasting for their late evening breakfast on our radios. It was pretty magical
- Can your "radio" be called that if they listen for sonic pulses ?
  I thought the term radio was exclusive to electromagnetic radiation, does the term also apply for sonars ?
  Or maybe bats also use some kind of EM waves to echo locate too ?
  Edit: not trying to be pendantic, I'm genuinely curious about this
  
  It is a radio though, no? If I tune in to 95.8 Khz to access Capitol FM's (bad) music, I'm hearing that radio band downshifted to 5-20 KHz on my speakers to make it audible for me.
  It's the same principle I thought for bats, I'm just tuning in to lower frequencies.

fractional distillation is just FFT for liquids…
- With extra phase changes?