TM 55-1510-221-MTF
PROCEDURE
TROUBLESHOOTING
REFERENCE
G.
AVIONICS FLIGHT CHECKS (CONT)
d.
Establish communications with a ground
station at least 150 miles distant on at
least three frequencies (one each from
the lower, middle, and upper frequency
ranges). Establish two-way
communications on AM and, when
possible, on USB. Obtain signal quality
reports from the other station and note
received signal quality.
NOTE
The intelligibility of SSB voice operations
becomes degraded when the receiver and
transmitter differ in frequency by a small
amount (approximately 50 Hz) The voice
pitch will sound either too high or too low
The cause may be either the receiver or
transmitter
e.
Frequency accuracy - Check as follows:
(1)
Station WWV - Select the frequency
that provides the best signal. The
station broadcasts on 2. 5000,
5.0000, 15.0000, 20.0000, and
25.0000 MHz. The higher the
frequency selected, the more
accurate the frequency check will
be.
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