I have a meter that will analyze limited RF spectrum in my area. One frequency that keeps coming up is 2.498 kHz. An FCC site listed that as the frequency used to communicate with underground mines. Is that correct, and if so, why would it be in my neighborhood?
There were a series of repeating frequencies, I'll list the most prominent, and hopefully you can tell me what most likely are producing them:
- 2.502 GHz,
- 672 MHz,
- 640 and 624 MHz,
- 72 MHz,
- 2.623 MHz is a constant,
- 550 kHz is a constant at -30 dbm,
- 378, and
- 471 kHz, all averaging -40 dBm.
That's a limited piece of data, but even that seems like alot. What are these coming from, and especially, is that 2.498 kHz really for communicating with mines? Thanks for your help.