Radio Shack TRC-488 owner manual Maximum Range, Reducing Noise

21-1585.fm Page 16 Thursday, August 5, 1999 9:39 AM

MAXIMUM RANGE

The maximum range and quality of CB transmissions vary depending on:

•The type and quality of antenna used.

•The height of the antenna’s mounting location (the higher the antenna, the better the reception).

•The surrounding terrain (moun- tains and tall buildings limit the range).

•The weather conditions.

•The number of nearby CBs oper- ating on the same channel.

•The standing wave ratio (SWR) between the antenna and the CB. You can set the SWR by using an SWR tester (such as Radio Shack Cat. No. 21-523). Follow the instructions that come with the SWR tester.

REDUCING NOISE

The Automatic Noise Limiting (ANL) circuit helps keep background noise to a minimum. However, strong sources of noise, such as your vehicle’s igni- tion, another radio, or spark plugs may be more than the circuit can compen- sate for.

16

If you operate the TRC-488 with the vehicle’s engine off, you should not have any problems with noise. If you use the CB with the engine on, you can determine the source of the noise by turning off the engine and operating the CB with the ignition set to ACC. If most or all of the noise goes away, the problem is in your vehicle’s ignition or electrical system.

Here are a few hints to help you reduce or eliminate such noise:

•Replace old ignition wires with new, high-voltage, noise-suppres- sion wires.

•Install noise suppressors on your spark plugs, or install new spark plugs that have built-in suppres- sors.

•Be sure that the ground connec- tion (black wire) is secure.

If problems persist, check your alterna- tor/generator, regulator, and gauges. Noise from these sources can be re- duced or eliminated using bypass ca- pacitors at the various output voltage points.

Your local Radio Shack store has a wide selection of noise-suppression accessories.