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9-28
1977 PONTIAC SERVICE MANUAL
CHECKING STANDING WAVE RATIO
NOTE: The SWR checking procedure requires that the transmitter be operated, and FCC
regulations governing C.B. radio operation apply. It would appear that three options are
available:
Have this test performed by a technician who holds a C.B. radio operator's license.
Acquire a dealership C.B. Radio Operator's license to allow technicians to use such
license during business hours.
Ask the vehicle owner or operator possessing a Permanent C.B. Radio license to
properly operate the transmitter during the test.
Yout attention is also called to the fact that C.B. radio adjustments or repairs within the
transmitter unit itself may only be performed by people holding an FCC Engineer's License,
Class 1 or Class 2. Adjustments or repairs referred to in this SWR procedure are limited to the
antenna itself or the antenna lead-in and connections.
NOTE: When adjusting SWR, the car must be a t least 20 feet away from any building.
Make certain that the ignition and the C.B. radio are turned off.
Disconnect the C.B. antenna from the C.B. radio.
Connect one end of the antenna jumper from the SWR meter to the C.B. radio antenna
socket.
Connect the other end of the antenna jumper from the SWR meter to the "Transmitter"
socket on the SWR meter.
Connect the C.B. antenna to the "Antenna" socket on the SWR meter.
Turn ignition and C.B. radio on and turn to channel 12 for 23 channel sets. Channel 20 for
40 channel sets.
Follow the SWR meter manufacturer's instructions on proper method of measuring SWR.
Now, key the microphone and read the SWR. If the SWR is 2.0 to 1 or lower, the antenna i s
properly adjusted. If the SWR i s higher than 2.0, adjust the length of the antenna. A reading
of 1.5 to 1 or lower is desirable.
Turn the radio and ignition off, remove the SWR meter and reconnect the antenna to the
radio.
CAUTION: Keying the microphone with the antenna disconnected may damage the radio.
SWR meters are available from local electronics supply outlets from $15.00 and up.
4479
Fig.
9-33
Adjusting Standing Wave Ratio
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