http://www.lazygranch.com/sound/beacons/basecamp209_2.wav
This is a navigation beacon that happens to have audio on it.  If you
are doing techo, you could sample the word "basecamp" and drop it in
periodically.

Basecamp does exist, unlike area 51 that just barely exists, but who
runs it is a good question. At one time I thought it was run by the
TTR, mostly because I followed a TTR truck from their base to basecamp.
However, basecamp has an EDACS repeater system just like Groom Lake, so
it more related to Groom Lake than the TTR.

Basecamp is far enough away from Groom Lake that there could  frequency
re-use, but that doesn't seem to be the case, i.e. basecamps
frequencies are unique.