[ARC5] Receiver sensitivity

[Jim Haynes]

And then for another strange receiver there is patent 2,513,384 for an
"aperiodic" receiver, used by the FCC in WW-II to detect clandestine
transmitters.

And there's the story about some GIs who escaped the Japanese invasion
of the Philippines by hiding in the jungles.  At least one group of them
had radio equipment and started transmitting on an international shipping
frequency.  Their transmissions were heard by Army monitors in S.F.
The leaders there decided to try to establish two-way contact, and
instructed their operators to pose as renegade hams who had not complied
with the wartime shutdown order.  So they were to carefully avoid using
any language that might identify them as military.