Radio Shack HTX-252 User manual

Cat. No. 19-1127
OWNER’S MANUAL
Please read before using this equipment.
HTX-252
2–Meter Amateur
FM Mobile Transceiver

2
FEATURES
Your RadioShack HTX-252 2–Meter FM Mobile Transceiver is a
compact and versatile transceiver, perfect either in your vehicle
or in your home. Vehicle cables and mounting hardware are sup-
plied. Add an optional base-station antenna, cable, and a power
supply to make it your home transceiver. It is an all-around ideal
choice for your amateur communications needs.
Note: You must have a Technician Class or higher Amateur Ra-
dio Operator’s License and a call sign issued by the FCC to legal-
ly transmit using this transceiver. Transmitting without a license
carries heavy penalties. Getting a license is easier than ever. See
“Introduction to Amateur Radio” on Page 7 for more information.
Here are some of your transceiver’s features.
High (25 Watt) and Low (10 Watt) Power Settings — let you se-
lect the best power setting according to communication guide-
lines.
10 Memory Channels and 1 Call Channel — let you store up to
10 frequencies for quick access along with other settings such as
the repeater offset and the CTCSS tones.
Frequency Range of 144–148 MHz (TX) and 136–174 MHz
(RX) —provide flexibility and excellent wide coverage. You can
also extend the transmit frequency range to 142.00–
149.885MHz.
Channel Up/Down and 16-Key DTMF on the Mic — lets you
manually send DTMF (Dual-Tone, Multiple Frequency) tones to
quickly access DTMF-access repeaters, autopatches, or other
stations equipped with a DTMF page feature.
CTCSS (Continuous Tone Coded Squelch System) Subaudible
Tone — both encodes and decodes 38 subaudible tones to help
reduce interference from other nearby systems operating on the
same frequency.
©2000 Tandy Corporation.
All Rights Reserved.
RadioShack is a registered trademark used by Tandy Corporation.

3
Programmable Frequency Step — lets you set the frequency
step for tuning or scanning to 5, 10, 12.5, 15, 20, 25 kHz.
Signal Strength Indicator — a graduated bar shows the relative
strength of the received signal and transmitting signal.
Digital Phase-Locked Loop (PLL) Frequency Synthesizer —
provides highly accurate and stable tuning.
Built-In Automatic Modulation Control — ensures a constant
RF modulation level.
Repeater Offset — lets you select the appropriate offset value to
match a local repeater.
Scan — the transceiver scans the frequency range and the mem-
ory locations for transmissions.
Rotary Tuning — lets you reach a desired frequency quickly and
accurately.
External Speaker Jack — lets you connect an optional external
speaker for more flexible operation.
Illuminated Digital Display — clearly shows the frequency, the
functions, and the signal strength.
Key Lock — lets you lock the transceiver’s keys to prevent acci-
dentally changing settings.

4
MANUAL CONVENTIONS
Some of your transceiver’s controls perform multiple functions.
The abbreviation or symbol for a function is printed on, or above
each multi-function button.
To activate certain transceiver features, you must press F (func-
tion) and then another button. Those key combination instruc-
tions are printed as the first button name, +, then the second
button name. For example, F+LOCK means press Fthen press
LOCK.
Control names are printed in small, bold, capital letters such as
CALL or VFO. Words, symbols, and numbers that appear on the
display are printed using a distinctive typeface, such as 146.94
or BUSY.
FCC INFORMATION
This device complies with Part 15 of the FCC Rules . Operation is
subject to the following two conditions: (1) This device may not
cause harmful interference, and (2) this device must accept any
interference received, including interference that may cause un-
desired operation.

5
CONTENTS
Introduction to Amateur Radio ............................................. 7
Preparation ............................................................................. 9
Attaching the Microphone Holder ..................................... 9
Mounting the Transceiver ................................................. 9
Connecting an Antenna ................................................... 11
Connecting the Microphone ............................................ 12
Using an External Speaker ............................................. 12
Connecting Power .......................................................... 13
Using the Transceiver as a Base Station ........................ 13
A Quick Look at the Controls ............................................. 15
A Quick Look at the Display ............................................... 18
Operation .............................................................................. 19
Turning the Transceiver On and Off ................................ 19
Selecting Frequencies .................................................... 19
Receiving Transmissions ................................................ 20
Transmitting .................................................................... 20
Understanding Repeaters ................................................... 22
Setting the Repeater Offset Frequency .......................... 23
Setting the Repeater Offset Direction ............................. 23
Reversing the Transmit and Receive Frequencies ......... 24
Memory Operation ............................................................... 25
Storing a Transmit/Receive Frequency ........................... 25
Recalling Memories ........................................................ 25
Using the Calling-Frequency Memory ............................ 26
Scanning Operation ............................................................. 27
Scanning for Active Frequencies .................................... 27
Scanning Standard Memory Locations ........................... 27
Continuous Tone Coded Squelch System Features ......... 28
Temporarily Opening Squelch ......................................... 28
Using DTMF Tones ............................................................... 30

6
Other Special features ......................................................... 31
Using Priority Frequency Monitor .................................... 31
Using VFO Priority ................................................... 31
Using Memory Priority .............................................. 31
Changing the Transmit Frequency Range ...................... 32
Selecting the Transmit Power Level ................................ 32
Locking the Keypad ......................................................... 32
Turning the Key Tone On and Off .................................... 33
Setting the Frequency Step ............................................. 33
Reducing Interference ..................................................... 33
Troubleshooting ................................................................... 35
Care and Maintenance ......................................................... 36
Resetting the Transceiver ............................................... 37
Replacing the In-Line Fuse ............................................. 37
Specifications ....................................................................... 38

7
INTRODUCTION TO AMATEUR RADIO
This transceiver is the perfect first radio for anyone entering the
exciting world of amateur radio, as well as a great additional
transceiver for the experienced amateur radio operator. This
transceiver opens a door for you to the world from almost any-
where! All you need is an Amateur Radio Operator’s License
(Technician Class or higher) issued by the Federal Communica-
tions Commission (FCC). If you do not have a license, it is easier
than ever to get one, and help from licensed operators is avail-
able. Here are a few tips to help you get started.
You can turn on your transceiver and scan the entire band to hear
what is going on; however, do not attempt to transmit until
you get your license. If you transmit without a license, you are
in violation of federal law that can lead to severe penalties. Note
that ham operators take the FCC rules very seriously and want
nothing to do with “bootleggers” — their term for people who op-
erate without a license.
Find out if there is a ham radio club in your area. Most clubs wel-
come newcomers and are glad to help you get your license.
There are thousands of clubs across the country, so there is prob-
ably one in or near your community. The staff at your local Ra-
dioShack store often can help you locate a club.
If you do not hear anyone talking about a local club as you listen
to local transmissions, write to the American Radio Relay League
(ARRL) at the following address to find out how to contact a local
affiliate. The ARRL is the national organization representing am-
ateur radio in the United States. The league has more than
150,000 members. Most are ham operators, or members in the
process of obtaining their license.
The American Radio Relay League
225 Main Street
Newington, CT 06111
http://www.arrl.org

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Start studying for the license exams. Do not be intimidated by the
word “study,” because most people can go from knowing abso-
lutely nothing about amateur radio to passing the Novice and
Technician written exams in less than a month.
The exams test your knowledge of basic radio regulations and el-
ementary radio theory. Many clubs hold license classes which
can be a fun and easy way to learn about amateur radio. There
are good books, cassette tapes, computer programs, and many
other study aids available. Your local RadioShack store sells
FCC
License Preparation
study guides for amateur radio operator li-
censes. While you are no longer required to learn Morse code for
a Technician Class license, we encourage you to learn it anyway
so you can advance to higher levels of operating privileges.
There is no fee to take the Novice exam. As soon as you pass the
Novice exam, you can immediately take the Technician exam.
There is a small fee required for taking the Technician exam. All
license level tests are administered by a three-member Volunteer
Examiner Team. Contact the ARRL for a schedule of exam op-
portunities in your area.
The Technician Class license lets you use this transceiver to
communicate directly with other operators, and use repeaters for
distant communication.
Amateur radio is a great hobby that has enriched the lives of mil-
lions of people all over the world. The ARRL would be glad to hear
from you if you need more information or would like to join!

9
PREPARATION
ATTACHING THE
MICROPHONE HOLDER
Follow these steps to attach the
microphone holder to your vehicle.
1. Using the holder as a tem-
plate, mark the position for the
mounting screw holes at the
desired location.
2. At each marked position, drill
a hole slightly smaller than the
supplied mounting screw.
Caution: Be careful not to drill
into anything behind the
mounting surface.
3. Use a Phillips screwdriver to attach the holder to the mount-
ing location with the supplied small self-tapping sheet metal
screws and lock-washers.
MOUNTING THE TRANSCEIVER
The most common mounting location for this transceiver is under
a vehicle’s dashboard. However, if you plan to use the transceiver
as a base station, you can place it on a desk, shelf, or table (see
“Using the Transceiver as a Base Station” on Page 13).
If you are mounting the transceiver in a vehicle, choose a loca-
tion where:
• you can easily reach the transceiver
• wires and cables are clear of the vehicle’s pedals or other
moving parts
• the transceiver is not directly in front of heating vents
• all wires and cables can reach their connection points

10
Caution: If you use the transceiver in a vehicle, mount it securely
to avoid damage to the transceiver or vehicle, or injury to anyone
in the vehicle during sudden starts or stops.
Follow these steps to mount the transceiver.
1. Using the mounting bracket as a template, mark the posi-
tions for the screw holes on the mounting surface,
2. In each marked location, drill a hole slightly smaller than the
supplied self-tapping screws.
Caution: Be care not to drill into objects behind the mount-
ing surface.
3. Using a Phillips screwdriver, attach the mounting bracket to
the mounting surface with the supplied mounting screws
and flat washers.
4. Attach the transceiver to the mounting bracket using the
supplied rubber washers and mounting knobs.
VOL
OP
SQ

11
CONNECTING AN ANTENNA
You must install an antenna before you can operate the trans-
ceiver. There are many different types of antennas suitable for
transceiver use. Each has its own benefits, Choose the one best
suited to your particular needs. Your local RadioShack store has
a wide selection from which to choose.
Note: If you are using the transceiver as a base station, see “Us-
ing the Transceiver as a Base Station” on Page 13.
When you install an antenna, keep in mind that, for the best per-
formance, you should mount the antenna vertically as high as
possible on the vehicle and away from sources of electrical noise.
Once you choose an antenna, follow it’s mounting instructions.
Then route the cable to the transceiver and thread the cable onto
the ANT connector on the back of the transceiver.
Cautions:
• Avoid routing the cable next to sharp edges or moving
parts, which might damage the cable.
• Do not run the cable next to power cables or other radio
antenna cables.
• Do not run the cable through the engine compartment or
other areas that produce extreme heat.
To take advantage of your transceiver’s maximum range, adjust
the antenna’s standing wave ratio (SWR) using an SWR meter
(not supplied, available at your local RadioShack store). Follow
the instructions supplied with the SWR meter and antenna to ad-
just the antenna’s SWR. Values of 2.0:1 are generally accept-
able, with readings of 1.5:1 or lower being more desirable.

12
CONNECTING THE MICROPHONE
1. Align the notch of the
microphone’s plug and
the microphone’s jack,
located on the left side of
the front panel. Then
insert the plug and turn
the metal ring clockwise
to secure the plug.
2. Slide the microphone onto the microphone holder.
To disconnect the microphone from the transceiver, turn the met-
al ring counterclockwise to loosen it.
Caution: Always disconnect the microphone by grasping its plug.
Never pull on the coiled microphone cable.
USING AN EXTERNAL SPEAKER
To hear your communications better in a noisy environment, you
can plug an optional, external speaker into the transceiver. The
speaker should have an impedance of 8-ohms and be able to
handle 3 to 10 watts of power. The speaker’s cable should have
a 1/8-inch (3.5-mm) plug.
To connect the speaker, insert the speaker cable’s plug into EXT.
SP on the back of the transceiver. This automatically disconnects
the built-in speaker.
MHz
F
DTMFON
CALL
STEPSCAN
PRILock
SHIFT

13
CONNECTING POWER
Follow these steps to power the transceiver from your vehicle’s
battery.
1. Connect the supplied polarized
13.8V DC power connector to
the white power socket and
cable on the back of the trans-
ceiver. The plug and socket only
fit one way. If you can not easily
insert the plug, turn it over and
try again. Do not force it.
2. Connect the red wire (+) (with
the in-line fuse holder) to a point in your vehicle’s fuse block
that supplies power only when the ignition is in the ACC
(accessory) or ON position.
3. Connect the black wire (–) to a metal part of the vehicle’s
frame (chassis ground).
Caution: Do not connect the black wire to a non-metallic
(plastic) part, or to any part insulated from the vehicle’s
chassis by a non-metallic part.
USING THE TRANSCEIVER AS
A BASE STATION
Although this transceiver is designed for mobile use, you can also
use it as a base station with a DC power source. To use the trans-
ceiver as a base station, you need these items:
• a regulated power supply that supplies at least 7 amps at
12V DC
Caution: Most 12–13.8V DC power supplies operate from a
standard AC outlet. Before connecting your transceiver to
this type of power supply, read and follow the instructions
included with it.

14
• a base station antenna
• coaxial antenna cable and appropriate connectors
Your local RadioShack store carries a wide selection of all prod-
ucts needed to set up your transceiver as a base station.
Follow these steps to use the transceiver as a base station.
1. Mount the base station antenna as described in its owner’s
manual.
Warning: Use extreme caution when you install or remove
a base station antenna. If the antenna starts to fall, let it go!
It could contact overhead power lines. If the antenna
touches a power line, contact with the antenna, mast, cable,
or guy wires can cause electrocution and death. Call the
power company to remove the antenna. Do not attempt to
do so yourself!
2. Connect the antenna to the PL259 ANT connector on the
back of the transceiver. If the antenna’s plug does not match
the ANT jack on the back of the transceiver, contact your
local RadioShack store for a suitable adapter.
3. Connect the supplied polarized 13.8V DC power connector
to the white power socket and cable on the back of the
transceiver. The plug and socket only fit one way. If you can
not easily insert the plug, turn it over and try again. Do not
force it. Then connect the red power wire with the in-line
fuse (+) and the black power wire (–) to the appropriate ter-
minals on your power supply.
4. Plug the power supply’s AC power cord into a standard AC
outlet.

15
A QUICK LOOK AT THE CONTROLS
Most of the controls on the transceiver have multiple functions.
The following charts should help you get a better idea of the func-
tion of each control.
Base Unit
Key/Control Use it to: Use with the F + Key to:
OFF/VOL Turn the transceiver on/
off. Adjust the volume. Reset the transceiver
SQ Set the squelch level to
block weak signals. N/A
REV Reverse the
repeater offset. N/A
VFO (T-SQ) Set the transceiver to
VFO mode. Set the tone squelch.
MR (MS) Recall a frequency in
memory. Store a frequency in memory.
Tuning Control Change the frequency
by the set STEP value. Change the frequency by 1 MHz
steps.
OFF/VOL Tuning Control
SQ REV VFO MR
(T-SQ) (MS)

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Microphone
Key/Control Use it to: Use with the F + Key to:
Push to
Talk (PTT) Transmit by holding it
down. Press to store a
setting.
Change the transmitting
power to high or low.
UP Increase the fre-
quency by the selected
step value.
Increase the frequency
in 1 MHz steps.
DN Decrease the fre-
quency by the selected
step value.
Decrease the frequency
by 1 MHz steps.
F (MHz) Temporarily open the
squelch. N/A
CALL
(STEP) Recall the calling fre-
quency memory. Set the frequency step.
PTT
DTMF
F (MHz)
CALL
(STEP) SCAN
(PRI) LOCK
(SHIFT)
DN
UP

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SCAN (PRI) Start and stop
scanning. Set the transceiver to dual watch mode.
LOCK
(SHIFT) Lock and unlock the
controlsexceptPTT,F,
VOL, and SQ.
Set the repeater
offset.
Alpha-
Numeric
Keys
Enter numerical val-
ues and DTMF control
letters.
N/A
DTMF Switch to DTMF
control. N/A
Microphone
Key/Control Use it to: Use with the F + Key to:

18
A QUICK LOOK AT THE DISPLAY
1. — appears when Fkey is pressed.
2. — indicates the keypad is locked.
3. — indicates a negative repeater offset.
4. — indicates a positive repeater offset.
5. SCAN — appears when the transceiver is scanning frequen-
cies.
6. PRI — indicates a priority frequency.
7. T— appears when Tone Squelch (CTCSS) is enabled for
transmission only.
8. T-SQ — appears when Tone Squelch (CTCSS) is enabled
for both transmission and reception.
9. Alpha-Numeric Display —shows frequency and operation
feature information.
10. TX — appears when the transceiver is transmitting.
11. 0to 9 —shows the memory channel in use.
12. BUSY —appears when the transceiver receives a signal.
13. — indicates signal strength; the stronger the
signal, the more boxes appear.
14. ME — appears when the frequencies and other station data
are being stored or while scanning data in memory loca-
tions.
Note: When you reset the transceiver, all display elements ap-
pear. See “Resetting the Transceiver” on Page 37.
FUNC

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OPERATION
TURNING THE TRANSCEIVER
ON AND OFF
To turn on the transceiver, rotate VOL clockwise until it clicks. The
last used frequency and other settings appear (the default fre-
quency is 142.50 MHz, with a frequency step of 5 kHz/.005 MHz).
To turn the transceiver off, rotate VOL counterclockwise until it
clicks.
SELECTING FREQUENCIES
To select a frequency in the VFO (variable frequency oscillator)
mode, use either UP or DN on the top of the microphone or the
tuning control.
Using either method lets you step up or down in increments which
you set using the Frequency Step option. (See “Setting the Fre-
quency Step” on Page 33“).
Rotating the tuning control changes the frequency by the value of
the step you set. You might want to set your preference for the
step value before you make other settings. Repeatedly pressing
(or holding down) UP or DN also changes the frequency by the
step value. To change the frequency by 1MHz steps, press Fso
appears. Then repeatedly press or hold down UP or DN.
The displayed frequency is typically shown to two significant dec-
imal places. However, depending upon the selected frequency
step, you might see a smaller number displayed to the right of the
second place. For example, 142.5075 lets you see the complete
frequency in use if you select 12.5kHz as your frequency step.
FUNC

20
RECEIVING TRANSMISSIONS
Follow these steps to receive standard transmissions.
1. With the transceiver on, rotate SQ counterclockwise until
you hear a hissing sound. Then slowly rotate SQ clockwise
just until the noise stops.
Notes:
•BUSY appears when the transceiver receives a standard
transmission or if the squelch is open.
• If the transceiver picks up unwanted and weak transmis-
sions, rotate SQ clockwise to prevent the squelch from
opening for these transmissions. If you want to hear
weak transmissions, rotate SQ counterclockwise. When
you do this, you might hear hissing between transmis-
sions.
2. Rotate the tuning control to select a frequency.
3. Set VOL to a comfortable listening level.
TRANSMITTING
There are two basic types of communication possible with this
transceiver: radio-direct-to-radio (simplex) or radio-to repeater-to
radio (duplex). Simplex operation uses the same frequency to
send and receive. Duplex operation uses one frequency to trans-
mit and another to receive. For more information about duplex,
see “Understanding Repeaters” on Page 22.
Caution: It is illegal to transmit if you do not have at least a Tech-
nician Class license issued by the FCC.
Follow these steps to transmit.
1. Select the desired frequency using the tuning control or UP/
DN until you are within the transmit frequency range.