Building a Scanner on Steroids with RTLSDR

What do you do if you want to make like the NSA and just listen to everything at once?

That is, without an NSA level budget?

Pull out your MacGuyver skills and get some RTLSDRs. In this 30C3 talk that I’ve been meaning to cover for a while, the guy shows how he wired up 4+ RTLSDRs in parallel to scan the whole spectrum much faster than would be possible with any other kind of radio. (At least, within a comparable price.)

This is particularly neat for TSCMers, as it makes it possible to quickly acquire a perspective on what the “normal” signals are in an area. When you walk in with your spectrum analyzer and start snooping, you can now say “oh, yeah, I saw that signal a few days ago a few hundred miles away, it pops up every once in a while.”

TSCM on a budget tip? JMA indicates that a spectrum analyzer with a sweep generator (particularly if the sweep is offset just a bit) makes a better NLJD than any dedicated NLJD. Sadly, one of the things about dedicated NLJDs is they’re EXPENSIVE.

It’s also a little dodgy to be buying TSCM equipment, and in an age of “interdiction” I’m always a little wary of anything that has to be mail-ordered.

On the other hand, companies like Rigol make reasonably cheap spectrum analyzers with built in tracking generators. (Looks like the retail price starts at $1495.) And as generic test gear, you can probably find a spectrum analyzer with tracking generator in a well-equipped electronics supply house.

For anyone looking out for ANGRYNEIGHBORs… think about picking one of these up!

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