Noisiest RF band for random number generation I've been looking into the difference between PRNGs and proper RNG techniques. One that I particularly like is the idea of tuning a radio to a certain frequency and bandwidth and just listening to the noise. Every so often (or continuously) pick a sample out of the noise and build a random number out of the samples.

There are a few obvious frequency ranges to avoid for this purpose:


Actual AM/FM radio stations (very predictable, not noisy at all)
TV stations (as above)
Protected RF bands (government, cellular, etc)


Based on noise-generating natural (and digital) phenomena, my question is: what frequency ranges are likely to be the noisiest and thus carry the most entropy for the purpose of a true random number generator?
This is not likely to be a good method to generate random numbers -- at least not on its own, without significant additional analysis.  You need a source of random numbers that is not only noisy, but also unpredictable to an adversary.  It's not clear that radio will meet that need.  If you listen on a FM band, an adversary who is nearby can also listen on the same FM frequency and will likely see something very similar to what you see, so will have a huge leg up in predicting the numbers you generated.

Bottom line: don't try to roll your own random-number source.  It's better to use a time-tested scheme, like a crypto-strength hardware RNG, or /dev/urandom, or a similar crypto-strength scheme.