The current models of Firestik no-ground-plane antenna kits may be used in a dual antenna configuration. If your vehicle already falls into the "no-ground-plane" category (plastic, fiberglass, thin aluminum) you are a candidate for no less than a single antenna no-ground-plane kit. When should you consider running twins?

• If you are pulling a large trailer and it blocks the radiation pattern of your antenna in one or more directions, you might want to consider having an antenna on both sides of your vehicle.

• If you have a high profile vehicle that limits antenna height, you can run two shorter antennas, By doing so you will double the antenna surface area available for transmitting and receiving without exceeding height limitations.

To double up, test and tune your dual NGP CB antennas,

1. Obtain two Firestik, single antenna no-ground-plane kits with the antenna and mount combination that will fit your specific requirements.

2. Visit your local electronics store and purchase a T-connector for PL-259 terminated coaxial cables. These T-connectors have two male ends to connect the coax cables to and one female end that will attach to the back of your CB.

3. Install the antenna kits on the vehicle per the instructions supplied with the kids. Connect the coax cable from each antenna to the male ends of the T-connector and than connect the female end to the "Antenna" side of your SWR meter. Connect a short jumper coax (a 1-2 ft cable with a PL-259 on both ends) from the "Transmitter" connector of the SWR meter to the CB radio.

4. Pull the vinyl tips from both antennas and set the gap between the top of the locking nut and the bottom of the tuning screw head (the exposed threaded portion of the tuning screw) between 3/8" (10mm) and 1/2" (13mm) and replace the antenna tips.

5. Test SWR in the normal manner, making note of the readings on Channel 1 and Channel 40. If the SWR on Channel 1 is higher than on Channel 40, pull both tips and increase the gap equally on both antennas. If the SWR on Channel 40 is higher than it is on Channel, decrease the gap equally on both antennas. Make adjustments until the SWR is about the same on both Channel 1 and Channel 40. Make sure that tips are installed during all SWR tests. If you make adjustments without the tips than install them afterwards, the SWR on Channel 40 will move upward causing an imbalance between the low and high channels.

6. Once adjusted, operate your equipment as if using any other antenna system.

Compliments of Firestik® Antenna Company, Phoenix, Arizona USA
Send e-mail   (tel) 602-273-7152  (fax) 602-273-1836

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