Apr/2006 - Honeywell KHF 1050 System Installation Manual

3. Upon completion of the tune cycle, the tune indication will disappear and the
display will return to a normal receive window. The receiver audio will likely be
different than it was prior to tuning the antenna and it may be necessary to
readjust the squelch if there is significant noise on the channel. The system is
now ready to transmit voice communications.
4. In order to ensure good audio quality of the transmitted signal, a
microphone-ground-loop test is recommended. To check for microphone
ground loops, select the AM mode on an unused frequency. Key the system
with no modulation, preferably covering the microphone element with your
hand.
Listen for any squeal or popping sound in the speaker or headphones. A squeal
or popping sound tends to indicate that a microphone ground loop exists.
Microphone ground loops will result in distorted audio. Such a ground loop is
usually the result of the microphone audio low line being tied to airframe ground
at multiple points.
5. Listen to the sidetone in the headphones or speaker while transmitting, both in
USB Voice (UV) and in AM. A raspy sound may indicate that RF interference is
feeding back into the HF or audio system.
6. While transmitting a voice test message in USB Voice (UV), observe other
electrical equipment in the aircraft and note any interference observed that
correlates to the HF transmission.
7. Voice communications should be established with a ground station or another
aircraft. See Paragraph
Revison 2
N
KHF 1050 SYSTEM INSTALLATION MANUAL
"7.B.(4) Post-Installation Test"
23-10-09
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Page 1008

Apr/2006