PRE-CHECKING ANTENNA INSTALLATIONS
Compliments of Firestik® Antenna Company Technical Support Team
Copyright © 1996 Firestik® Antenna Company
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One of the most frustrating problems for both the CB'er and the factory technician is dealing with and/or fixing a bad installation. In too many instances the user installs the mount and routes the coax through nooks and crannies only to learn later that the location creates a horrible SWR situation. Now you have holes in the vehicle and hours of time invested in a bad installation. Sometimes we get lucky and can fix the problem by grounding a mount, adding a spring to change the antenna position relative to ground plane, or by using a longer antenna. But, in many cases there is no fix for a bad installation. You could save yourself a lot of time and aggravation by doing a false install followed by an SWR test. Try positioning the mount and antenna in the location that you would like it to be located. If you can find a way to temporarily fasten the mount at that point with a c-clamp, vise grip or other device than you can pre-test the installation. Note: If you are installing a standard antenna kit, versus a no-ground-plane kit, you will need to ground the mount before testing the SWR. With the mount secured and the antenna in place, run the coax on the outside of the vehicle from the mount to the radio/SWR meter and attempt to tune the antenna. If you are able to tune the antenna and achieve SWR below 2.0:1 on all channels, you can permanently mount the antenna and route the coax with some confidence. Transmitting antennas are very sensitive to objects within their radiation field, especially those objects that are closer than 12-16 inches from the antenna. Keep that in mind when doing the install. If you mount and tune the antenna on an empty luggage rack and fill it up later, you may find a whole new set of numbers on your SWR meter. Unless you have experience in antenna installations, you might save yourself a lot of time and aggravation by using a false install procedure before making a permanent commitment. To see an article on bad installations, click here. |
