Radio Shack 20-006A User Manual

© 1996 Tandy Corporation.
All Rights Reserved.
RadioShack is a trademark used by Tandy Corporation.
Cat. No. 20-006A
Telescoping Antenna for Portable Scanners
and Walkie Talkies
You can use this telescoping antenna for either receiving or transmitting. You can
use it as a
receiving
antenna from 25 MHz through the 1296 MHz Ham Band, and
you can use it as a
1
/
4
wavelength
transmitting
antenna from 130 MHz through 535
MHz.
USING THE ANTENNA FOR TRANSMITTING
For transmitting, you must set the antenna length as close as possible to the trans-
mitting frequency’s
1
/
4
wavelength. This ensures the best possible transmission by
using the proper standing wave ratio (SWR).
Cautions
:
• When you use the antenna to transmit, you must always collapse the section
located just above the loading coil. If you do not, you might damage the
antenna and/or your radio.
• When you use the antenna to transmit, you must calculate the
1
/
4
wavelength
and adjust the antenna length accordingly. If you do not do this, you can dam-
age your transmitting equipment due to an improper standing wave ratio
(SWR).
Use this formula to calculate the proper length for a
1
/
4
wavelength transmitting an-
tenna:
2834
Freq. in MHz
=
Antenna Length in Inches
Example: 2834
147 (MHz) =19.3 Inches
20-006.fm Page 1 Tuesday, August 3, 1999 2:25 PM

Radio Shack 20-006A Specifications

General

FM Frequency Range	88-108 MHz
AM Frequency Range	540-1600 kHz
Power Source	Passive (no power required)
Frequency Range	540-1600 kHz (AM), 88-108 MHz (FM)
Impedance	75 ohms

Summary

Transmitting Antenna Setup

Calculating Transmitting Length

Formula and example for calculating 1/4 wavelength transmitting antenna length for optimal SWR.

Transmitting Cautions and Best Practices

Essential warnings regarding antenna collapse and SWR damage during transmission.

Receiving Antenna Setup

Optimizing Reception Lengths

Guide for adjusting antenna length for best reception across various frequency bands.

Frequency Bands and Antenna Lengths

Specific antenna length settings for different frequency ranges like VHF, Ham, and UHF.

Product Warranty Information