Preparation, Pre-Tuning the Antenna | Radio Shack 10M specs

21-869.fm Page 3 Wednesday, October 13, 1999 11:50 AM

PREPARATION

Pre-Tuning the Antenna

Your antenna is preset to use 27.205 MHz (the middle of the CB band) for the lowest SWR. If you are using your anten- na with a CB radio, you do not have to pre-tune it. See “Assembling and Mount- ing the Antenna” on Page 3.

Before you assemble and mount the an- tenna, you must determine the frequen- cy range you will be using with it. If you are not using CB frequencies, you must either trim the antenna’s top element to match the range you are using or use an antenna tuner (not supplied) to electri- cally trim the antenna.

Caution: To avoid damaging the anten- na, do not trim the antenna’s middle or bottom elements.

If you are using your antenna with an amateur radio and want to trim the an- tenna’s top element to pre-tune it, follow these steps.

1.Use the following chart to determine how much you need to trim off of the top element (if any).

For example, to pre-tune the antenna to use a frequency of 29.328 MHz, you must cut off enough of the top element (about 21 inches) to leave it approximately 51 inches in length.

2.Remove the cap from the top of the top element.

3.Use a tape measure to measure the length you need to cut off of the top element, then use a hacksaw to carefully cut the top element.

4.Replace the cap on the top element.

5.Set the tuning rings on the bottom element of the antenna to their low- est position.

Note: If you trim too much off of the top element or use the antenna for a differ- ent frequency later, you can order a re- placement top element from your local RadioShack store.

If you need to pre-tune the antenna to a frequency lower than 28 MHz, use an antenna tuner (not supplied).

Assembling and Mounting the Antenna

Before you can use the antenna, you must assemble and mount it then con- nect it to your radio. You can mount the antenna outdoors on a vertical, solid ob- ject such as a TV antenna mast. For the best results, mount the antenna vertical- ly as high as possible away from trees or other obstructions. (Higher frequencies are noticeably affected by obstructions.)

Important:

•Do not mount the antenna on a metal surface such as aluminum siding. This greatly reduces the antenna’s ability to receive signals.

•Before you assemble the antenna, prepare the structure that you will mount it to. RadioShack stores carry standard TV masts which you can use to mount the antenna. Make sure the supplied U-bolts will fit around whichever mast you choose.