TM 55-1680-351-10
WARNING
Leave the radio in the BCN 243.0 posi- tion until
search planes, ships, or vehicles appear in the
immediate vicinity. Failure to do so will interfere with
direction-finding equipment and could result in
termination of search activities. Continue this mode
for at least 14 hours or until search vehicles are
contacted. Battery and beacon failure is indicated by
loss of beacon sidetone in the speaker (or
earphone). If more than one AN/PRC-90 is available,
use only one at a time and share batteries to extend
the transmission period.
(4)
Prior to visual contact with search craft, and if reasonable
doubt exists as to proper beacon operation, occasional brief voice or mew
("Mayday" or "SOS") transmissions can be made. Limit such
transmissions to daylight hours for best propagation. Follow a 2-minute-
on, 1-minute-off; 3-minute- on, 2-minutes off; and 10-minute-on
procedure. Make the "Mayday" and/or "SOS" transmissions once just
after sunrise, once at noon, and once near sundown to take advantage of
improved propagation. Meteorological conditions will affect transmission
range and quality.
3-13
