Setting the SWR (Standing Wave Ratio)

The Rule

If the SWR, measured on the Highest Frequency is worse than the SWR measured on the Lowest frequency, the Length of the Antennae is too Long, if the reverse is true, then the antennae is too short.

Setting the SWR Step by Step.

Step 1:Ensure that you SWR Meter is inline and check the Weather Conditions if its Damp or Wet false readings may be obtained.
Step 2: Select the Lowest Channel (frequency) on your Transciever.
Step 3: Select the FWD (Forward) or CAL (Calibrate) function on your meter, depress the "Mic" (PTT) key and adjust the Needle on the meter to the "Set" or "CAL" position on the Scale. Then Release the PTT Key
Step 4: Select the REF or SWR position switch, Press the PTT key and note the reading obtained.
Step 5: Select the Highest Channel (Frequency) on your Transciever and REPEAT steps 3 and 4
Step 6: Now Apply "The RULE" to the 2 readings obtained and Adjust the Length of your Antennae accordingly.
Step 7: repeat steps 3 and 6 until you have obtained similar readings on both the frequencies, this will be the best compromise antennae length for the frequencies you will be using.

Problem Guide

If this is much too high at the extremes but good in the middle frequencies, then your antennae is too tightly tuned for your frequency range, you may need to obtain a wider band antennae.

If the SWR is too high on all Frequencies, the likely causes could be:

Poor Earthing of your Antennae
Damaged Coaxial Cable
Antennae location (too close to building or obstruction)
Ground plane too small (mobile antennae's)

On 1/2 and 5/8 Wave Antennae's it is vital that none of the mounting pole protrudes above the mounting bracket. 3ins of pole WILL produce an SWR of 2.5:1 which refuses to be affected by adjustment of the Antennae.

Correctly carried out, this operation is worth every minute of the time it takes, the benefits are less interference, greater range and more importantly longer transciever life.

If you have difficulties with setting your SWR correctly on your antennae, ask a friend or fellow CB'er or Radio Ham Enthusiast for assistance, they may be able to solve some of the usual problems with Antennae Erection, Alternatively you may seek professional help in erecting your Antennae, this maybe a little more expensive, but can be considered as a worthwhile investment, as all work carried out will be subject to statutory guarantees.