[ARC5] Pipsqueack info

[David Stinson]

>From Mike's link to Wikipedia:

Battle of Britain
In the Battle of Britain, "Huff-Duff" was the mechanism used by the RAF to
track the location of their fighter squadrons in the air. RAF fighters had a
HF channel of their radios set to broadcast a signal for fourteen seconds of
every minute. A clockwork mechanism regulated this broadcast, which was
codenamed "Pipsqueak".

Each Fighter Command sector had HF/DF receiving stations that would monitor
the Pipsqueak broadcasts and telephone the bearings back to the sector
control rooms where they could be triangulated and the squadron's location
plotted.