A military radio changes frequency 77,000 times a second.
Light only travels 3.9 kilometres in the time it sits on one.

That’s what actually defeats a jammer. To jam a hop you have to detect it,
retune, transmit, and have your signal physically arrive — all within 13
microseconds. Even with perfect electronics, anything more than about two
kilometres away is too far. The speed of light says no.

And parking on one frequency doesn’t work either. Against 2,320 channels you’d
corrupt 0.04% of the hops. Error correction eats that without dropping a word.
To actually matter you’d need 2,320 times the power.

One correction though: hopping isn’t encryption. Encryption hides what you said.
Hopping hides that you spoke at all — which is what stops someone finding you.

Explained in 3D.

Which would you rather protect — your message, or your position?#rfengineering #signalprocessing #frequencyhopping #engineering #spreadspectrum