Cat. No. 19-1126
OWNER’S MANUAL
HTX-242 TWO-METER MOBILE TRANSCEIVER
Please read before using this transceiver.
INTRODUCTION
Your HTX-242 Two-Meter Mobile Transceiver is an exciting addition to Radio Shack’s growing line of high-quality amateur radio equipment. It offers some of the most advanced, and most requested, features available in a mobile transceiver. Be sure to read this entire manual to understand how to use all the radio’s features.
You must have a Technician Class or higher Amateur Radio Operator’s
!transceiver. Transmitting without a license carries heavy penalties. Getting a license is easier than ever. Your local Radio Shack store has train- ing materials for all classes of Amateur Radio Operator.License and a call sign issued by the FCC to legally transmit using this
FEATURES
Auto Memory Store (AMS)—automatically searches for active frequencies and stores them in memory, including the appropriate repeater offset.
High (45 Watt) and Low (10 Watt) Power Settings—let you select the best power setting for effective communications.
True FM Modulation—provides a clear, natural-sounding signal.
41 Memory Channels—hold one calling frequency and 40 standard frequencies.
Priority Memory Channel 1—lets you set the HTX-242 to periodically check the frequency stored in Memory Channel 1 and alert you if there is activity on it.
Individually Programmable Repeater Offsets —let you program different repeater offset frequencies for each memory, and a default repeater offset for manually-tuned frequencies.
Subaudible Tone Transmit and Receive (CTCSS) —transmits the subaudible tones required to use some repeaters, and also lets you set a subaudible tone that your transceiver must receive to open squelch.
DTMF Page with Group Calling—lets you set a sequence of up to seven DTMF tones that your transceiver must receive to sound an alert tone and open squelch.
DTMF Transmit and Memory —lets you manually send DTMF tones or send DTMF sequences of up to 15 digits each from one of 10 DTMF memories to quickly access DTMF-access repeaters, autopatches, or other stations equipped with a DTMF page feature.
1996 Tandy Corporation. All Rights Reserved.
Radio Shack is a registered trademark used by Tandy Corporation.
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Programmable Frequency Step—lets you set the frequency step for tuning or scanning to 5, 10, 12.5, 20, 25, 50, or 100 kHz.
Extended Band Coverage —receives from 136 to 174 MHz and lets you extend transmit coverage to include 2-Meter ham, MARS (Military Amateur Radio Service), and CAP (Civil Air Patrol).
Dual VFO (Variable-Frequency Oscillator) and Duplex Modes— two independent VFOs let you quickly select between two directlyentered frequencies. You can also use one of the VFOs as a repeater input frequency and the other as a repeater output frequency for odd-split repeaters.
Using this Manual
To make this manual as easy to use as possible, we give you several ways to find information.
Contents—lists all sections in the order they appear in the manual.
Understanding the Display—lists all display indicators and gives a brief explaination and notes the sections where the indicator is fully explained.
Using the Menu—lists the options in the configuration menu and gives the page numbers where the options are discussed.
Quick Reference Card—gives brief instructions for most functions.
Type Conventions—make the references to keys and displays easier to find in the text:
•Keys are bold. For example, VFO.
•When a key has more than one marking (for example, DTMF and ALM refer to the same key), we refer to the key by the name appropriate to the task.
•Where you are instructed to press two keys at once, the keys are separated by a + symbol. For example, F+DTMF.
•Text and symbols that appear on the transceiver’s display appear in a special typeface. For example, 144.940.
Important notes in this manual have a large exclamation mark (!) in the margin. Warnings and cautions you should follow to prevent injury to a person or damage to the transceiver have a large lightning bolt ( 
) in the margin.
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CONTENTS
Installation . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 6
Unpacking the Transceiver . . . . . . . . . . . . . . . . . . . . . . . . . 6 Connecting the Microphone . . . . . . . . . . . . . . . . . . . . . . . . . 6 Mounting the HTX-242 in a Vehicle . . . . . . . . . . . . . . . . . . . 7 Connecting an Antenna . . . . . . . . . . . . . . . . . . . . . . . . . . . . 8 Connecting to your Vehicle’s Power . . . . . . . . . . . . . . . . . . . 9 Using the HTX-242 as a Base Station . . . . . . . . . . . . . . . . 10 Using the HTX-242 with Packet Radio . . . . . . . . . . . . . . . . 11 Connecting an External Speaker (Optional) . . . . . . . . . . . . 11
Understanding the HTX-242 . . . . . . . . . . . . . . . . . . . . . . . 12
Dual VFO Modes . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 12
DTMF (Touch-Tone) Features . . . . . . . . . . . . . . . . . . . . . . 12
Subaudible Tone (CTCSS) Features . . . . . . . . . . . . . . . . . . 13
Repeater Operation . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 13
Memory Channels . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 13
Understanding the Display . . . . . . . . . . . . . . . . . . . . . . . . 14
Basic Operation . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 16
Turning On/Off Your HTX-242 . . . . . . . . . . . . . . . . . . . . . 16 Resetting the HTX-242 . . . . . . . . . . . . . . . . . . . . . . . . . . . 16 Extending the Transmit Frequency Range . . . . . . . . . . . . . 16 Setting Volume and Squelch . . . . . . . . . . . . . . . . . . . . . . . 17 Using the Light . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 17 Setting the Power Level . . . . . . . . . . . . . . . . . . . . . . . . . . . 17 Locking the Controls . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 17 Selecting a Frequency . . . . . . . . . . . . . . . . . . . . . . . . . . . . 18
Directly Entering a Frequency . . . . . . . . . . . . . . . . . . . 18 Tuning to a Frequency . . . . . . . . . . . . . . . . . . . . . . . . 18 Scanning for a Frequency . . . . . . . . . . . . . . . . . . . . . . 19 Setting the Frequency Step . . . . . . . . . . . . . . . . . . . . . . . . 19 Setting the Scan Options . . . . . . . . . . . . . . . . . . . . . . . . . . 20 Storing Scan Skip Frequencies . . . . . . . . . . . . . . . . . . 20 Setting the Scan Resume Condition . . . . . . . . . . . . . . 20 Setting the Scan Resume Delay . . . . . . . . . . . . . . . . . . 21 Setting the Scanning Range . . . . . . . . . . . . . . . . . . . . 21 Receiving Transmissions . . . . . . . . . . . . . . . . . . . . . . . . . . 22 Transmitting . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 22 Manually Transmitting DTMF Tones . . . . . . . . . . . . . . 23 Transmitting DTMF Tones from Memory . . . . . . . . . . . 23 Limiting Transmit Duration . . . . . . . . . . . . . . . . . . . . 24 Turning the Keytone Beep On and Off . . . . . . . . . . . . . . . . 24
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Advanced Operation . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 25
Frequency Offset Defaults . . . . . . . . . . . . . . . . . . . . . . . . . 25 Turning Auto Duplex On and Off . . . . . . . . . . . . . . . . 25 Changing the Default Offset . . . . . . . . . . . . . . . . . . . . 26 Reversing the Offset . . . . . . . . . . . . . . . . . . . . . . . . . . 26 Overriding the Duplex Offset . . . . . . . . . . . . . . . . . . . . 26
Using the Dual VFOs for Duplex Operation . . . . . . . . . . . . 27
Using Memory Channels . . . . . . . . . . . . . . . . . . . . . . . . . . 28
Storing a Frequency . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 28 Changing Stored Settings . . . . . . . . . . . . . . . . . . . . . . . . . 28 Using Auto Memory Store (AMS) . . . . . . . . . . . . . . . . . . . . 29 Tuning to a Standard Memory Channel . . . . . . . . . . . . . . . 30 Using the Calling-Frequency Memory . . . . . . . . . . . . . . . . 30 Checking Priority Channel 1 . . . . . . . . . . . . . . . . . . . . . . . 30 Scanning Memory Channels . . . . . . . . . . . . . . . . . . . . . . . 31 Clearing a Memory Channel . . . . . . . . . . . . . . . . . . . . . . . 31 Enabling/Disabling Scanning for Memory Channels . . . . . 31
Using DTMF and Subaudible Tones . . . . . . . . . . . . . . . . . . 32
Storing a DTMF Sequence . . . . . . . . . . . . . . . . . . . . . . . . . 32
Transmitting a DTMF Sequence . . . . . . . . . . . . . . . . . . . . 32
Using DTMF Page . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 33
Using Group Calling . . . . . . . . . . . . . . . . . . . . . . . . . . 33
Using Auto-Reply . . . . . . . . . . . . . . . . . . . . . . . . . . . . 34
Using DTMF Auto Send . . . . . . . . . . . . . . . . . . . . . . . . . . . 35
Using Subaudible Tones . . . . . . . . . . . . . . . . . . . . . . . . . . 36
Valid Subaudible Tones . . . . . . . . . . . . . . . . . . . . . . . 36
Setting the Subaudible Tones . . . . . . . . . . . . . . . . . . . 36
Activating Subaudible Tone Transmit and Squelch . . . 37
Setting the DTMF Page and Subaudible Tone Alert . . . . . . 37
Using the Menu . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 38
Troubleshooting . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 40
Error Codes . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 40
Common Problems and Solutions . . . . . . . . . . . . . . . . . . . 40
Replacing the Fuse . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 41
Specifications . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 42
Schematics . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 44
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INSTALLATION
Unpacking the Transceiver
As you unpack the transceiver, check to be sure you have all the items shown in this illustration.
Connecting the Microphone
Plug the microphone’s connector into the microphone jack, secure the microphone holder to either the left or right side of the transceiver, then clip the microphone to the holder.
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Mounting the HTX-242 in a Vehicle
When you select a mounting location for the HTX-242, be sure:
•You can easily reach it
•No wires or cables will interfere with the vehicle’s operation
•It is not directly in front of heating vents
•All wires will reach their connection points
Cautions:
•To avoid damaging your vehicle’s electronic systems, contact your vehicle’s manufacturer before you install the HTX-242 to find out about the proper transceiver mounting locations, antenna locations, and power and antenna cable routing guidelines.
•Do not apply power to the transceiver until after you properly mount and connect an antenna.
Use the supplied screws, metal washers, bracket, rubber washers, and mounting knobs, as shown, to mount the transceiver.
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Connecting an Antenna
You can connect a variety of antennas for both mobile and basestation use (see “Using the HTX-242 as a Base Station” on
Page 10). Each type of antenna has its benefits. Choose one that best meets your needs.
When deciding on a mobile or base-station antenna and its location, consider the following:
•The antenna should be as high as possible on your vehicle or house.
•The antenna and antenna cable should be as far away as possible from sources of electrical noise (ignition systems, power cables, and so on).
•The antenna should be vertical.
•The antenna should have an SWR of less than 1.5:1. An SWR of 1.8:1 or greater can prevent the HTX-242 from performing to its specified ratings.
After you select an antenna, follow its mounting instructions. Then route the antenna cable from the antenna to the HTX-242 and connect it to the antenna connector.
Connect the antenna to your HTX-242 using 50-ohm coaxial cable. The cable should end in a PL-239 connector.
Cautions:
•To prevent damage to your HTX-242, you must connect an antenna to it before you operate it.
•Do not run the cable over sharp edges or moving parts that might damage the cable.
•Do not run the cable through the engine compartment or other areas that produce extreme heat.
•Check with your vehicle manufacturer for antenna cable routing guidelines.
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Connecting to your Vehicle’s Power
Follow these steps to power the HTX-242 in your vehicle.
1.Connect the black wire to your vehicle battery’s negative (–) terminal or to a metal part of the vehicle’s frame. Be sure the metal part is not insulated from the vehicle’s frame by a plastic part.
2.Connect the red wire to a source of voltage that turns on and off with the ignition and that can handle the transceiver’s 10-amp maximum power draw.
Or, if you do not want the HTX-242 to turn on and off with your vehicle’s ignition, connect the red wire directly to the battery’s positive (+) terminal.
!Note: You might need to connect the red wire directly to the battery if you experience ignition noise.
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Using the HTX-242 as a Base Station
Although we designed the HTX-242 primarily for use as a mobile transceiver, you can also use it as a base station. To do so, you need these items:
•13.8-Volt DC regulated power supply that can supply at least 10 amps continuous power
•Base station antenna
•50-ohm coaxial antenna cable and connectors
Follow these steps to connect the HTX-242 as a base station.
1.Mount the base station antenna according to its instructions.
Warning: For your safety, follow all cautions and warnings included with the base station antenna.
2.Connect the antenna cable to the antenna jack on the back of the HTX-242.
3.Connect the black power wire to the power supply’s negative
(–) terminal.
4.Connect the red power wire to the power supply’s positive (+) terminal.
5.Connect the power supply to a source of power.
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Using the HTX-242 with Packet Radio
You can connect your HTX-242 directly to a packet radio terminal node controller, as shown below.
Note: You can purchase an 8-pin plug that matches your HTX242’s MIC jack at your local Radio Shack store (Cat. No. 279-440).
Connecting an External Speaker (Optional)
You can connect an external speaker to your HTX-242.
Use an 8-ohm communications or PA speaker that can handle 5 or more watts of power (such as Radio Shack Cat. No. 21-549). The speaker’s cable must end in a 1/8-inch plug. Simply plug the speaker cable into the HTX-242’s EXT. SP jack.
If your vehicle has a cassette player, you can easily connect your transceiver to your vehicle’s audio system using a CD-to-cassette adapter and a mono-to-stereo audio plug.
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UNDERSTANDING THE HTX-242
This section explains some of the HTX-242’s features. See “Basic Operation” on Page 16 for instructions about how to use these features.
Dual VFO Modes
The VFO (Variable-Frequency Oscillator) modes let you directly select a frequency anywhere within the HTX-242’s operating range. Your HTX-242 has two VFOs: VFO-A and VFO-B. You typically use the VFOs to tune to frequencies you have not stored into one of the HTX-242’s memory channels (see “Memory Channels” on Page 13).
A related feature of the HTX-242 lets you transmit on the frequency selected with one VFO and receive on the frequency selected with the other VFO. (See “Using the Dual VFOs for Duplex Operation” on Page 27.)
DTMF (Touch-Tone) Features
DTMF (Dual-Tone, Multiple Frequency) is another term for touchtones (the tones a telephone produces when you press a digit). This standard set of tones is used by many different amateur radio systems for accessing programmable features and dialing through autopatches.
Your HTX-242 produces all 16 standard DTMF tones (0-9, , #, A, B, C, and D). It has 10 DTMF memories which can each hold up to 15 digits for quick transmission. You can also set the HTX-242 to listen for a specific set of DTMF tones, and alert you when it detects them (this feature is called DTMF Paging). Until it hears the sequence, the HTX-242 does not pass any transmissions to the speaker.
Group Calling lets you DTMF page a single person or an entire group of people. To use group calling, every person in the group selects the same first three digits as their DTMF page sequence. They then select up to four additional digits unique to each person. To page an individual, you transmit their entire DTMF page sequence. To page the entire group, you transmit at least the first three digits of the sequence, followed by the DTMF tones for A, B, and C.
! |
Note: Group Calling only |
works with the HTX-242 and other transceivers |
that support this feature. |
|
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Subaudible Tone (CTCSS) Features
Subaudible tones, also known as CTCSS (Continuous Tone-Coded Squelch System) are low-frequency tones that are mixed with a transmission. They are used by many repeaters to limit interference from other nearby radio transmitters. When a repeater uses a subaudible tone, it does not react to any transmission that does not include that tone.
Your HTX-242 includes all 38 standard subaudible tones. You can set your HTX-242 to include any of these tones with your transmissions. You can also set your HTX-242 to limit reception to only those transmissions that include the selected tone.
Repeater Operation
Operation through a repeater, where you transmit on one frequency and receive on another, is called duplex operation. Operation direct to another station where you transmit and receive on the same frequency is called simplex operation.
A repeater is a station that receives signals on one frequency (the input frequency) and then retransmits them on a different frequency (the output frequency). Repeater antennas are typically at the tops of tall buildings or on antenna towers, so a relatively lowpower signal can reach the repeater. The repeater retransmits the signal at a higher power. This gives users of low-power transceivers the ability to communicate over a much greater range.
To use a repeater, you must know the repeater’s input and output frequencies. Repeaters are usually identified by their output frequency. Thus, a repeater that has an output frequency of 146.94 is referred to as the 146.94 repeater. To determine the input frequency you must know the frequency offset (600 kHz for most of the 2-meter band) and the offset direction (+ if you add 600 kHz to the output, or – if you subtract 600 kHz from the output).
Your HTX-242 is programmed with the default 600 kHz frequency offset and direction for the 2-meter band. See “Frequency Offset Defaults” on Page 25. When you tune to a frequency that is normally assigned for repeater use, the HTX-242 automatically selects the correct input frequency if you turned on the AS option.
Memory Channels
Your HTX-242 has 41 memory channels (40 standard memory channels and one calling-frequency memory channel). Each memory channel can hold a transmit and receive frequency, subaudible transmit and receive tones, the transmit power level, and whether subaudible tone transmit and squelch are on or off. The HTX-242 can even scan a selected range and automatically store active frequencies in unused memory locations.
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Understanding the Display
One or more of the following indicators appear when you turn on and use your HTX-242.
VFO-A or VFO-B — appears when you select one of the VFO modes. See “Dual VFO Modes” on Page 12.
VFO-A-T
VFO-B — appears when you select the DUP-A mode (transmit on VFO-A and receive on VFO-B). See “Using the Dual VFOs for Duplex Operation” on Page 27.
VFO-A
VFO-B-T — appears when you select the DUP-B mode (receive on VFO-A and transmit on VFO-B). See “Using the Dual VFOs for Duplex Operation” on Page 27.
BUSY — appears when the HTX-242 is receiving a transmission. See “Receiving Transmissions” on Page 22.
FUNC — appears after you press F. Flashes after you hold F for at least 1 second.
LOCK — appears when you lock the HTX-242’s functions. See “Locking the Controls” on Page 17.
T — appears when transmit subaudible tone is turned on. See “Using Subaudible Tones” on Page 36.
T-SQL — appears when both transmit subaudible tone and subaudible tone squelch are turned on. See “Using Subaudible Tones” on Page 36.
ALT — appears when you turn on the DTMF page/subaudible tone alert. See “Setting the DTMF Page and Subaudible Tone Alert” on Page 37.
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+ or – — indicates the duplex offset direction. See “Overriding the Duplex Offset” on Page 26.
DTMF — appears when you turn on DTMF squelch. See “Using DTMF Page” on Page 33.
HIGH or LOW — indicates the transmit power level. See “Setting the Power Level” on Page 17.
ON-AIR — appears when you transmit. See “Transmitting” on Page 22.
— appears when you turn on the Channel 1 alarm. Flashes when there is a transmission on Memory Channel 1 and the alarm is turned on. See “Checking Priority Channel 1” on Page 30.
M-CH — appears when you tune to a memory channel. See “Memory Channels” on Page 13.
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