1. Choose a clear location to adjust the SWR
Antennas are very sensitive to objects close to them. Go to an open
area to tune your antenna, such as a parking lot. This can be done
at home, providing you are not close to the house. Do not try to
tune inside a building, under trees, near or under power lines, nor
with someone standing next to the antenna. This distorts the signal
and causes a reflection back into the antenna giving false readings.
Also, close all doors, the hood and trunk lid.
2. Setting the SWR
Test with the radio only. If you have an amplifier, either
turn it off, or preferably remove from installation.
Insert the antenna whip into chrome antenna adjustment
mast at the top of the coil.
Using either the meter built into the radio or a good
external SWR meter, calibrate on channel 20. Switch back
to SWR and record the readings on three channels 1, 20, &
If the lowest SWR reading occurs on channel 1, the
antenna whip is to long and must be shortened. Loosen the
mast set screws and lower the whip 1/4 into the mast.
Tighten mast set screw and again read SWR. Repeat until lowest
SWR is obtained. If the whip is fully lowered into mast and the SWR is still high,
remove the whip from mast. Using a hacksaw, grinder, or bolt
cutters, cut 1/4 from the bottom part of the whip. Re-insert the whip
into the mast and test again for SWR. Repeat the above procedure
until the SWR is below 1.5 of all channels.
If the lowest SWR reading occurs on channel 40, the antenna whip
is to short and must be raised. Loosen the mast set screws and
raise the whip 1/4, re-tighten set screws and test SWR again.
Repeat the above procedure until the SWR is below 1.5 of all