[Milsurplus] LF on aircraft 1941

[Hue Miller]

Was reading memoirs of Admiral Karl Doenitz "Ten Years
and Twenty Days" where is an interesting paragraph on
aircraft LF usage. German U-boats were having a difficult
time locating Allied convoys North Atlantic. Kondor FW-200
patrol planes would locate the convoy and radio back 
location info to U-boat HQ. But having flown largely during
darkness hours and not having accurate course deviation
(due to lack of navigation fixes) planes would not infrequently
be off their estimated location by up to 80 miles. The solution
arrived at in July 1941: the patrol plane sighting a convoy, would
report to HQ via HF. HQ would flash this info to all subs with
the order to stand by for LF direction finding. The aircraft would
then transmit on LF a beacon signal. ( How long? I don't know.
Maybe 15 minutes, or less? )  Submarines available in the area
would take bearings on the LF signal and report this along with
their own known positions, to HQ. HQ would then plot on their 
map board the triangulated position of the convoy and broadcast
it to all U-boats.
I saw a graphic of this in some German WW2 magazine, which
may come to adorn some article or posting later. It kinda surprised
me to see this revealed in a popular magazine but then i suppose
there's no secret really revealed, this was just a variation of standard
scouting.
-Hue Miller