How to ADJUST YOUR SWR
on your CB radio and Why.
Equipment needed: SWR
meter, short jumper coax 3 foot.
The SWR meter needs to be placed in line between the antenna and the CB.
Connect the antenna (normally connected to the back of the CB ) to the connector marked
"Antenna" or "Ant" on your SWR Meter. Connect one end of the
short jumper coax to the "transmit" or "Xmit" on the SWR meter.
Connect the other end of your jumper coax to the CB.
Assuming you have a standard SWR meter the switches should read
as follows: REF or SWR, FWD, and there should be a slide switch marked "set" or
"Adjust". If different consult your meter's owners manual.
With the radio on the lowest channel (1 on CB) and the SWR meters switch in the Forward
(FWD) position, depress the transmit switch (key up) located on the microphone. While
holding the unit in this transmit mode, adjust the meter needle to the set position using
the Set or Adjust knob on the meter. As soon as the needle is in alignment with the
corresponding mark on the meter face, flip the switch to the Reference (REF) position. The
meter is now showing your SWR on channel one. Note the value and quickly release the
microphone switch. Record this reading.
Repeat the previous step on channels 19 and 40.
How to read your results: If SWR on
channels 1, 19 & 40 is below 2.0, your radio can be operated safely.
If SWR on all channels is above 2.0 but not in the "red zone" (normally over
3.0), you may be experiencing coaxial cable reaction (bad quality, wrong length, etc.),
insufficient ground plane, or have an ungrounded antenna mount.
If SWR is in the "red zone" on all channels, you probably have an electrical
short in your coax connectors, or your mounting stud was installed incorrectly and is
shorted. Do not operate your radio until the problem is found,
serious damage can occur to your radio.
If SWR on the lowest channel is higher than it is on the highest channel, your antenna
system appears to be electrically short. Your antenna length may need to be increased.
If the SWR on channel 40 is greater than that on channel 1, your antenna is considered
to be "LONG" and reduction of physical height and/or conductor length will
correct this situation.