Off-volume control - Turn clock-wise, set
volume as required.
Frequency selector - Set desired frequency.
Fly aircraft to a point 40 nautical miles away
from test station.
communication with test station each 10
while flying a 360 flat turn (not to exceed 5
uniformly loud and clear through these tests.
Repeat procedure for frequencies in low,
middle, and high ranges.
HF radio set - Check as follows.
Transmitter selector switch (audio control
panel) - #4.
Mode selector (HF control panel) - Set
desired operating mode.
Microphone switch - Press momentarily and
wait for antenna coupler to tune./ A 1000
Hz tone will be hear in the headphones until
tuning is complete. Verify that tuning time
does not exceed 30 seconds.
Establish communications with a ground
station at least 150 miles distant on at least
three frequencies (one each from the lower,
Establish two-way communications on AM
and, when possible, on USB. Obtain signal