Nat NT030, Installation And Operation Manual

Page: 17 / 56

VHF Transceiver Manual SM05 Rev 4.00
Nov 26, 2003 Page 1-7
ENG-FORM: 800-0107.DOT
CONFIDENTIAL AND PROPRIETARY TO NORTHERN AIRBORNE TECHNOLOGY LTD.
NEVER make a HI-POT test on this RF coax cable, unless the transceiver is KNOWN
TO BE DISCONNECTED. Failure to follow this information will result in a damaged
transceiver which is not covered by warranty!
DO NOT ATTACH THE TAC/COM TRANSCEIVER until the above conditions are met.
2.3.6.2 Performance
Checks
a)
Power up the ship's system with the Tac/Com control head and R/Ts installed,
and turn on all of the radios and other accessories required for this system.
b)
Check for correct radio operation and channeling, both receive and transmit, and
Ensure that all status indications are correct (TX and SQ) Do not proceed until
the radios are operating correctly. You may have to set the DISPLAY
CONTRAST pot (on the LCD controls), or use the CONTRAST/BRIGHTNESS
screen (reached after the last radio with the "RADIO" button) to obtain a suitable
display.
c)
Check each antenna feedline at the R/T with a through-line wattmeter and
suitable frequency elements to Ensure correct antenna matching. Reflected
power in excess of 25% represents a serious problem, and should be
investigated carefully, or serious RFI and system interference as well as possible
radio damage may result. Check that forward power is to specifications over the
required band, as specified for the radio in use.
2.3.6.3 Diagnostic
Hints
Ensure all antenna mounts are secure, cleanly grounded, and well terminated. Avoid
sharp cable bends in the coax. Never mount any antenna on a composite surface
unless a well grounded and adequately sized ground plane has been provided.
Unusual buzzes, hums or other background audio are symptomatic of multiple grounds,
or noisy external systems such as blowers or pumps sharing wiring with the audio
system connections. Failure to key or correctly modulate a transmitter is often caused
by forgetting to connect all required grounds to the radio or external audio system.
A special caution is that no ground should be taken from the front panel, or similar
location, that shares a ground return with a turn and bank, horizon, or other motor
driven instrument. If this caution is not observed, the sound of the motor may be heard
mixed in with receiver audio.