*6:/642"4//GVGT192EO"&WCN"$CPF"(/"#OCVGWT"6TCPUEGKXGT
19-1108
OWNER’S MANUAL — Please read before using this equipment.
Thank you for purchasing a RadioShack HTX-420 2-Meter/70 cm Dual Band FM Amateur
Transceiver. Your transceiver is compact and rugged, making it easy to carry almost anywhere.
The crystal controlled circuitry provides accurate and stable frequency selection, making it an
ideal choice for your amateur communications needs.
%106'065
Preparation .................................................................. 2
Using Internal Batteries ........................................... 2
Using AC or DC Power ............................................ 2
Connecting the Antenna .......................................... 2
Attaching the Belt Clip ............................................. 2
Attaching the Wrist Strap ......................................... 2
Connecting a Microphone/Speaker ......................... 2
A Quick Look At the Display ........................................ 3
Operation ..................................................................... 4
Manual Conventions ................................................ 4
Turning On/Off the Transceiver ................................ 4
Setting the Squelch Level ........................................ 4
Temporarily Opening Squelch .................................. 4
Using the Universal Type Keys ................................ 4
Selecting Frequencies (Direct Tuning) and Receiving
Transmissions .......................................................... 4
Transmitting ............................................................. 4
Understanding Repeaters ............................................ 5
Setting the Repeater Offset Frequency ................... 5
Turning Repeater Operation On/Off and Changing
The Offset Direction ................................................. 5
Memory Operation ....................................................... 5
Storing a Transmit/Receive Frequency .................... 5
Recalling Memory Locations .................................... 5
Checking Memory Location Settings ....................... 6
Clearing a Single Memory ....................................... 6
Using the Calling-Frequency Memory ..................... 6
Scanning Operation ..................................................... 6
Scanning for Active Frequencies ............................. 6
Scanning Standard Memory Locations .................... 6
Skipping Memory Channels While Scanning ........... 6
Continuous Tone Coded Squelch System Features
(CTCSS) ...................................................................... 6
Setting the CTCSS Tones ........................................ 6
Using the CTCSS Tones .......................................... 7
Using DTMF Code ....................................................... 7
Transmitting a DTMF Code ...................................... 7
Using the Transceiver with Packet Radio ................ 7
Locking the Keypad ................................................. 8
Lighting the Display ................................................. 8
Turning the Key Tone On and Off ............................ 8
Setting the Frequency Step ..................................... 8
Power Save ............................................................. 8
Using Auto Power Shutoff ........................................ 8
Limiting Transmit Duration (Time-Out Timer) ........... 8
Tuning the Weather Radio Frequencies .................. 8
Using the SAME Alert .............................................. 8
Using the Electronic Compass ................................. 9
Selecting the Transmit Power ................................ 10
Cross Band Channel Operation ............................. 10
Dual Watch ............................................................ 10
Receiving the Air Band .......................................... 10
Changing the Transmit Frequency Range ............. 10
FCC Information ........................................................ 10
Care ........................................................................... 10
ERR Display .......................................................... 10
Service and Repair .................................................... 11
Resetting the Transceiver ...................................... 11
Specifications ............................................................ 11
Electronic Compass — provides two letters to
indicate direction (such as SW or NW) and up to
three digits to show directional angle (such as
360°, 180°, 90° or 45°). See “Using the
Electronic Compass” on page 9.
Full 16-Key DTMF (Dual-Tone Multi
Frequency) Keypad — lets you dial and
make telephone connections. See
“Transmitting a DTMF Code” on page 7.
Programmable Frequency Steps — let
you set the frequency increment for
tuning or scanning to steps of 5, 6.25, 7.5,
10, 12.5, 15, 20, 25, or 50 kHz. See
“Setting the Frequency Step” on page 8.
SAME Weather Alert — uses Specific
Area Message Encoding (SAME) digital
information to determine and display the
level of weather events. See “Using the
SAME Alert” on page 8.
and want nothing to do with “bootleggers” –
their term for people who operate without a
license. ±
+0641&7%6+10"61"
#/#6'74"4#&+1
Amateur radio is a great hobby that has
If you do not hear anyone talking about a
enriched the lives of millions of people all
local club as you listen to local transmissions,
over the world. Your transceiver is the perfect
write to the American Radio Relay League
first radio for anyone entering the exciting
(ARRL) at the following address to find out
world of amateur radio, or as a great
how to contact a local affiliate. The ARRL is
additional transceiver for the experienced
the national organization representing
amateur radio operator. Your transceiver
opens a door for you to the world from almost
anywhere! All you need is an Amateur Radio
amateur radio in the United States. The
league has more than 150,000 members.
Most are ham operators, or members in the
Operator's License (Technician Class or
process of obtaining their license.
higher) issued by the Federal
Communications Commission (FCC). If you
The American Radio Relay League
do not have a license, it is easy to get one,
and help from licensed operators is available.
Find out if there is a ham radio club in your
area. Most clubs welcome newcomers and
"+/2146#06"
#
#
225 Main Street
Newington, CT 06111
If an icon appears at the end of a paragraph, go
to the box on that page with the corresponding
icon for pertinent information.
are glad to help you get your license. Here
Start studying for the license exams. Most
Rý— Warning
— Important
#
are a few tips to help you get started.
people can go from knowing absolutely
. — Caution
± — Note
nothing about amateur radio to passing the
You can turn on your transceiver and scan
Technician written exam in less than a
month.
the entire band to hear what is going on;
however, do not attempt to transmit until
±"016'"±"
You must have a Technician Class or higher
Amateur Radio Operator's License, and a call
sign issued by the FCC, to legally transmit using
this transceiver. Transmitting without a license
carries heavy penalties.
you get your license. If you transmit without
The exams test your knowledge of basic
a license, you are in violation of federal law
radio regulations and elementary radio
that can lead to severe penalties. Ham
theory. Many clubs hold license classes
operators take the FCC rules very seriously
which can be a fun and easy way to learn
© 2002 RadioShack Corporation.
All Rights Reserved.
RadioShack and RadioShack.com are trademarks
used by RadioShack Corporation.
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rubber dust cover from the SPK and MIC
jacks on top of the transceiver. Then insert
the plug of an optional voice-activated
headset with microphone, or an optional
communication headset, into the jacks. . ±
The following schematic diagram shows the
typical wiring for an external mic and
speaker.
."%#76+10".
Use only microphone and speaker accessories
that do not share a common ground for the
speaker and the microphone. Doing otherwise
might damage the transceiver.
You can also connect an optional mono
earphone to the SPK jack. This lets you use
the transceiver's push-to-talk button (PTT) to
transmit as usual. Your local RadioShack
store carries a wide selection of suitable
communications headsets, earphones, and
separate components.
±"016'"±"
Connecting a headset’s plug to the transceiver’s
SPK jack automatically disconnects the internal
speaker.
#"37+%-".11-"#6"6*'"&+52.#;
3
4
5
6
7
1
2
16
15
8
9
10
14
13
11
12
1. — appears when F (function) key is
11. 2-Digit Number below
— indicates
o
y
pressed.
memory location number.
2. J — appears when Tone Squelch
12. Sub Frequency Display (appears on the
bottom of the display) — shows the
(CTCSS) is enabled for transmitting. SQ
appears when Tone Squelch (CTCSS) is
enabled for receiving. TSQ appears
when Tone Squelch (CTCSS) is enabled
for transmitting and receiving.
transmit frequency and other settings. In
the compass mode, the display shows
direction indicator and angles in degree.
13. Signal Strength/Power Meter — shows
the relative signal strength or power
level.
3. + — appears to indicate a positive
repeater offset. – indicates a negative
offset.
14.
— appears and flashes when power
p
4. JEJ — appears when a time for the time-
save is on.
out timer is selected.
15. C — indicates the output power is
middle. B indicates the output power is
low. When neither of these appears, the
output power is high.
5. 7F — appears when Auto Power Off is
enabled.
6.
— appears when the SAME alert is
enabled. The icon flashes when the
transceiver is out of range.
r
16. Main Frequency Display (appears in the
middle of the display) — shows the
receive frequency.
í
7.
— indicates the battery strength.
17. 7 — appears when the transceiver tunes
to the air band. (Not shown on this
display.)
8. z — indicates the keypad control is
disabled to prevent accidental setting
changes.
9.
— appears when you use the cross
q
band feature.
10.
(Memory Channel Recall) —
o
appears when you recall a memory
channel.
3
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setting mode.
IGB,
L><
HFJ,
K><
HFJ,
HN
JED;,
12'4#6+10
JN JED;, ZJC<, 7H;7, and I7C; appear.
/#07#."%108'06+105
Your transceiver's buttons perform multiple
functions. The abbreviation or symbol for a
function is printed on, above, or below each
button.
8
9
, or rotate CH to change the
Press
or
value of the selected setting. Press
or
PTT to store the setting and exit.
The detailed operation for squelch, VHF
repeater offset, UHF repeater offset, receive
tone squelch (CTCSS), transmit tone squelch
(CTCSS), DTMF, SAME area code, and
SAME on/off is described in the relevant
sections.
To activate certain transceiver features, you
must press F (function) and another button at
the same time. Those key combination
instructions are printed as first button name,
+, then the second button name. For
example, F+TOT means hold down F while
you press TOT.
5'.'%6+0)"(4'37'0%+'5"*&+4'%6"
670+0)+"#0&"4'%'+8+0)"
64#05/+55+105
Button names are printed in small, bold,
capital letters such as CLR or MR. Words,
symbols, and numbers that appear on the
display are printed using a distinctive
typeface, such as '*,$/*& or CH.
1. Repeatedly press
to select the
desired receiving mode (VHF, UHF, Air,
Weather).
2. Select a frequency using one of the
following methods.
6740+0)"1011(("6*'"
64#05%'+8'4
Using CH: Rotate CH clockwise or
counterclockwise to select a frequency
(or channel for the weather band). The
frequency changes in increments you
set (see “Setting the Frequency Step” on
Page 8) for each rotation click. Hold
down F while rotating CH to change the
frequency by 1 MHz increments
regardless of the selected step
frequency.
To turn on the transceiver, press PWR. The
radio beeps once if the key tone feature is
enabled. Then the current battery voltage
briefly appears and the last used frequency
appears. To turn the transceiver off, press
PWR again.
5'66+0)"6*'"537'.%*".'8'.
Turn on the transceiver then repeatedly press
±"016'"±"
Temporarily Opening Squelch
The current setting for Squelch, Repeater Offset
for the selected band, RX Tone, and TX Tone
can be displayed by pressing and holding M.
(see “Setting the CTCSS Tones” on Page 6).
6
7
or
until the current squelch setting (&&
8
9
: Repeatedly press (or
Using
hold down)
frequency appears. Hold down F while
and
8
to &+) and IGB appear. Repeatedly press
9
or
until the desired
8
9
or
or rotate CH to change the squelch
setting. A higher number reduces noise in-
between transmissions while a lower number
allows you to hear a weak transmission.
8
9
pressing
or
to change the
frequency by 1 MHz increments.
Selecting Frequencies and Receiving
Transmissions
Press
or PTT (Push to Talk) to store the
Using Direct Key Entry: Use the number
keys to directly enter a frequency,
including the three numbers to the right
of the decimal. (You do not enter the
decimal point.) ±
setting and exit squelch setting.
•
When you directly enter a frequency, the
transceiver accepts only six digits and it
automatically rounds down the last digit of
the frequency to 0 or 5. For example, if you
enter 440.244, your transceiver accepts it as
440.240. If you enter 440.248, the
transceiver accepts it as 440.245. If you set
the frequency step to 6.25 kHz, 7.5 kHz, or
12.5 kHz, you need to select frequencies
using CH, or 8 or 9.
6'/214#4+.;"12'0+0)"
537'.%*
If you use the Tone Squelch (CTCSS) feature
(see “Setting the CTCSS Tones” on Page 6),
you might not hear a transmission on the
current frequency. To temporarily open the
squelch so you can hear all transmissions on
the frequency, hold down M. To resume
normal operation, release M. ±
3. Set VOL to a comfortable listening
level. ±
64#05/+66+0)
There are two basic types of communication
possible with this transceiver: radio-direct-to-
radio (simplex) or radio-to-repeater-to radio
(duplex). Simplex uses the same frequency
to send and receive. Duplex uses one
frequency to transmit and another to receive.
For more information about duplex, see
“Understanding Repeaters” on Page 5. .
•
If the transceiver picks up unwanted, weak
transmissions, set the squelch to a different
level (See “Setting the Squelch Level” on
Page 4).
75+0)"6*'"70+8'45#."6;2'"
-';5
Repeatedly press
until the transceiver
."%#76+10".
It is illegal to transmit if you do not have at least a
displays a frequency from the desired band.
The band changes in the following order:
VHF, UHF, AIR, WX.
1. Select the desired transmit band VHF/
UHF and frequency using manual or
direct entry.
Technician Class license issued by the FCC.
6 7
allows
Repeatedly pressing
or
selection of squelch, VHF repeater offset,
UHF repeater offset, receive tone squelch
(CTCSS), transmit tone squelch (CTCSS),
DTMF, SAME area code, and SAME on/off
2. Hold the transceiver about 3 inches from
your mouth.
4
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8 9
, or rotate CH
to change the offset to a new value
ranging from .000 to 8.000 MHz.
3. Hold down PTT (Push to Talk), then
speak slowly and clearly into the
microphone.
2. Repeatedly press
or
7
4. Release PTT when you finish
3. Press
until K>< HFJ appears.
transmitting.
8 9
4. Repeatedly press
or
, or rotate CH
to change the offset to a new value
ranging from .000 (no offset) to 8.000
MHz.
70&'456#0&+0)"
4'2'#6'45
5. Press
exit.
or PTT to store the setting and
A repeater is a radio that receives a signal on
one frequency (the input frequency) and
retransmits that signal on a different
frequency (the output frequency). Repeater
antennas are typically located at the tops of
tall buildings or on antenna towers, so a
relatively low-power signal can reach the
repeater. The repeater retransmits the signal
at a higher power. This gives your transceiver
the ability to communicate over a much
greater range.
6740+0)"4'2'#6'4"12'4#6+10"
1011(("#0&"%*#0)+0)"6*'"
1((5'6"&+4'%6+10
To use the transceiver with a repeater, you
must set either a + or – repeater offset
direction. To turn on operation for use with a
repeater in the VFO mode, press F++/–. The
current offset indicator (+ or –) appears. To
turn off repeater operation, repeatedly press
F++/– until neither + or – appears.
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 (typically 600 kHz for the 2-
meter band and 5 MHz for the 70-cm band)
and the offset direction (+ if you add the
offset (600 kHz) to the output, or – if you
subtract the offset (600 kHz) from the output).
If you want to reverse the repeater input and
output frequencies, press F+REV.
/'/14;"12'4#6+10
Your transceiver has 100 standard memory
locations that you can use to store
frequencies for quick access. You can store
frequencies used for the VHF, UHF, AIR, and
WX bands. When you store a frequency,
other settings associated with that frequency
(such as the repeater offset and CTCSS
tones) are stored as well. ±
Whether the offset is positive or negative
depends on:
• which part of the band the repeater
operates on
5614+0)"#"64#05/+614'%'+8'"
• local convention
(4'37'0%;
• proximity of repeaters using the same
two frequencies
1. Select the frequency you want to store.
±"016'"±"
To determine the offset and the direction,
obtain a copy of The ARRL Repeater
Handbook (available through your local
RadioShack store or the ARRL). That
publication lists the locations of repeaters as
well as their frequency and offset information.
Once you select a frequency, the other
values such as the repeater offset and
the CTCSS tones for that repeater are
also stored in the memory location. To
select other settings, see “Setting the
Repeater Offset Frequency” on Page 5,
“Setting the CTCSS Tones” on Page 6,
and “Using DTMF Code” on Page 7.
Setting the Repeater Offset Frequency
This setting only affects the VFO mode. If you
saved a frequency offset in a memory location,
that setting is not affected.
Memory Operation
You cannot activate or deactivate the power
save, auto power-shut off, time-out timer,
frequency step, key tone on and off, and call
features in memory mode.
A + above the displayed frequency indicates
a positive offset, while a – above the
frequency indicates a negative offset. If
neither +, nor – appears, the transceiver is
set for simplex operation.
2. Press F+MW.
flashes and the lowest
o
vacant memory location appears.
8 9
or turn CH to
3. Repeatedly press
or
select the desired memory location.
5'66+0)"6*'"4'2'#6'4"1((5'6"
4. Press MW or F+MW again to store the
selected frequency and exit the memory
mode. If a memory location already has
a frequency stored in it, the new
(4'37'0%;
The transceiver’s default repeater offset is
600 kHz for the VHF band and 5 MHz for the
UHF band. As the display shows all
frequencies in MHz, you see $,&& (MHz) for
VHF and +$&&& (MHz) for UHF. ±
frequency is stored in its place.
4'%#..+0)"/'/14;".1%#6+105
6
7
1. Repeatedly press
appears.
or
until L>< HFJ
To recall a saved memory location, press MR.
appears and the last used memory
o
5
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8
location number appears beneath
. Then
2. To change the scan direction, press
o
8# 9
9
turn CH or press
different memory location. To return to VFO,
or
to select a
or
or rotate CH.
3. To stop on a frequency or to stop
press
.
scanning, press SC or PTT.
%*'%-+0)"/'/14;".1%#6+10"
5%#00+0)"56#0&"/'/14;"
5'66+0)5
.1%#6+105
To check all the settings stored in a memory
1. Press MR (so
appears), then press
o
8
location, press MR, then rotate CH (or use
±"016'"±"
Clearing a Single Memory
SC. The decimal point flashes while the
transceiver scans all but empty
locations.
9
or
) to select the desired memory location.
Then hold down M. The settings stored in the
memory location appear in sequence starting
with the squelch setting value and ending
with the frequency.
You cannot clear memory location number 1.
Skipping Memory Channels While
Scanning
You cannot skip memory channel &'.
2. To change the scanning direction, press
8
9
or
or rotate CH.
3. To stop scanning, press SC, PTT, or
.
%.'#4+0)"#"5+0).'"/'/14;
Follow these steps to clear any single
memory location. (To clear all memory
locations, see “Resetting the Transceiver” on
Page 11.)
5-+22+0)"/'/14;"%*#00'.5"
9*+.'"5%#00+0)
While scanning memory channels, you can
skip channels you do not want to receive.
You cannot use this feature for normal
frequencies.
1. Press MR.
and the last used memory
o
location number appear.
8
9
, or rotate
2. Repeatedly press
or
To skip a channel, select the channel in
CH, to select the desired memory
location.
memory mode, then press F+M (SKIP).
o
flashes. Press SC to scan memory channels.
You can also skip a channel when the
transceiver stops while scanning by pressing
F+M (SKIP). The transceiver resumes
scanning after you press F+M (SKIP).±
3. Press F+CLR (6). The selected memory
location is cleared. ±
75+0)"6*'"%#..+0)/(4'37'0%;"
/'/14;
To clear a channel (turn off skip) skip
memory, press F+M (SKIP).
The calling-frequency memory location lets
you quickly jump to a specific frequency. The
preset calling frequency is 146.520 MHz in
the VHF band and 446.000 MHz in the UHF
band. You can store a different frequency
into this memory, as well as other settings
associated with that frequency, such as the
repeater offset and CTCSS tone. You can
use this feature when the transceiver is in
VFO mode.
%106+07175"610'"
%1&'&"537'.%*"
5;56'/"('#674'5"
*%6%55+
Your transceiver can transmit and receive a
low-level, selectable subaudible tone at the
same time as it receives (RX) or transmits
(TX) a regular signal. This special tone lets
you listen only to other radios set to the same
tone frequency when you use the transceiver
in simplex operation. The CTCSS feature
also lets you match your HTX-420 to the
subaudible tone frequency used by a local
repeater.
Press CALL to display the current calling
frequency. The frequency (such as 146.520)
and 9 appear. Press CALL again to return to
VFO mode.
To change the stored frequency, select a
new frequency, then press F+ CALL (CM).
5%#00+0)"12'4#6+10
5'66+0)"6*'"%6%55"610'5
To set the RX and TX tones for the
transceiver, follow these steps.
5%#00+0)"(14"#%6+8'"
(4'37'0%+'5
6
7
1. Repeatedly press
appears.
or
until HNýJED;
1. To search for activity on a frequency,
press SC. The transceiver begins to scan
up or down the band’s full frequency
range. The decimal point flashes as the
transceiver scans. The displayed
frequency stops on each active
frequency for 8 seconds.
8
9
, or rotate CH to select a
2. Press
or
frequency or no frequency (9J9IIýe\\)
from the table Page 7.
7
3. Press
until JN JED; appears.
6
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8
9
, or rotate CH to select a
4. Press
or
functions, which is handy if you are involved
with repeater administration. You can also
signal to another radio equipped to receive
DTMF codes.
tone frequency from the list on Page 7.
and exit.
5. Press
or PTT to store the settings
6
7
1. Repeatedly press
or
until ZJC<
appears. If no DTMF codes are stored in
75+0)"6*'"%6%55"610'5
You can use a transmit tone, a receiver tone,
or both. For example, if the selected repeater
uses a receive only CTCSS tone, enable the
transmit tone but not the receive tone on the
HTX-420.
memory, UýUýUýýUýUýU and Zýb appear.
8
9
, or turn CH
2. Repeatedly press
or
to select the desired DTMF memory
location.
3. Enter up to 16 characters (0 through 9,
To enable only the transmit (TX) tone, press
F+T.SQL (1). J appears above the displayed
frequency. Press PTT to store the setting.
and A through F; E= , F=#). The radio
∗
sounds a short beep for each entry, and
a long beep to indicate the sixteenth
character. If you try to enter more than
16 characters, the radio sounds two
short beeps.
To enable only the receive (RX) tone, press
F+T.SQL (1) again. IG appears above the
displayed frequency. Press PTT to store the
setting.
4. To confirm the DTMF characters, hold
8 9
down F and rotate CH, or press
or
To enable both the transmit (TX) and
receive (RX) tones, press F+T.SQL (1) again.
JIG appears above the displayed frequency.
Press PTT to store the setting.
to scroll it. If you make an entry error,
press F+CLR (6) and repeat Step 3
again.
To enter another DTMF sequence,
repeat Steps 2–4.
When you store a frequency in one of the 100
memory locations, all settings chosen for the
selected frequency are stored as well. Before
you store a frequency (see “Storing a
Transmit/Receive Frequency” on Page 5),
select the Subaudible Tone Frequencies first.
5. Press
or PTT to store the sequence
in the selected memory location. The
transceiver returns to the VFO mode.
64#05/+66+0)"#"&6/("%1&'
You can transmit a DTMF code from stored
memory or by direct entry.
5WDCWFKDNG"6QPG"(TGSWGPEKGU"**\+
67.0
69.4
71.9
74.4
77.0
79.7
82.5
85.4
88.5
91.5
94.8
97.4
100.0
103.5
107.2
110.9
114.8
118.8
123.0
127.3
131.8
136.5
141.3
146.2
151.4
156.7
159.8
162.2
165.5
167.9
171.3
173.8
177.3
179.9
183.5
186.2
189.9
192.8
196.6
199.5
203.5
206.5
210.7
218.1
225.7
229.1
233.6
241.8
250.3
254.1
64#05/+66+0)"#"&6/("%1&'"
(41/"5614'&"/'/14;
1. Press F+D.SEL. The last stored DTMF
sequence appears.
8# 9
, or rotate
2. Repeatedly press
or
CH until you see the desired DTMF
memory location. Then press PTT to exit.
3. Select a transmit frequency (see
“Selecting Frequencies (Direct Tuning)
and Receiving Transmissions” on
Page 4).
4. Press PTT+
to transmit the selected
DTMF code using the selected
frequency.
64#05/+66+0)"#"&6/("%1&'"
75+0)"&+4'%6"'064;
1. Hold down PTT (Push to Talk).
75+0)"&6/("%1&'
DTMF (Dual-Tone Multi Frequency) tones
are those typically associated with the use of
your telephone. Your transceiver can
transmit up to 16 separate DTMF tones and
store a sequence of tones in up to 6 different
memory locations (d1 to d6). You can use
DTMF to transmit to a land-patch that is
connected to a telephone line. This also lets
you enable or disable certain repeater
2. Enter each character of the desired
DTMF code in order. The DTMF tone
sounds to confirm your entry. ±
±"016'"±"
You can also hold down PTT and enter the first
character of the DTMF sequence. Then, release
PTT and continue to enter the balance of the
characters as long as you enter each character
within one second of the proceeding character
entry.
75+0)"6*'"64#05%'+8'4"9+6*"
2#%-'6"4#&+1
You can connect your transceiver directly to
a packet radio terminal node controller
7
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(TNC). See the following diagram for a
suggested connection. Refer to your TNC
instructions for details.
1. Press F+APO (3). Auto Power Shutoff is
normally disabled. e<< appears.
8
9
, or
2. Repeatedly press either
or
turn CH to select a time period until
power shutoff. You can select e<<, )&, ,&,
/& or '(& minutes.
3. Press PTT or
to store your selection
HTX-420
TNC
Computer
and exit.
To turn off auto power-shutoff, press F+APO
again and select e<<.
.1%-+0)"6*'"-';2#&
To lock the transceiver’s keypad so you do
not accidentally change a setting, press
F+LOCK (DW). This locks all buttons except
PTT, PWR, F, and M.
.+/+6+0)"64#05/+6"&74#6+10"
*6+/'/176"6+/'4+
When you communicate using repeaters,
keep your transmissions as brief as possible.
Most repeaters have built-in timers that limit
single transmissions to 3 minutes or less.
You can set the transceiver to stop
transmitting if you exceed a set time limit with
a single transmission.
To unlock the keypad, press F+LOCK (DW)
again.
.+)*6+0)"6*'"&+52.#;
When you press any key except PTT or F, the
backlight turns on for about 5 seconds. Press
M to turn on the backlight.
To set a value for the time-out timer, press
F+TOT (4). The default setting e<< appears
6740+0)"6*'"-';"610'"10"
8
9
,
along with JEJ. Repeatedly press
or turn CH to select the desired time-out
or
#0&"1((
interval (up to 20 minutes). When you select
a value for the time out feature, JEJ appears.
The transceiver is preset to sound a beep
each time you press a key. To turn off the
beep, press F+BEEP. 8F-E<< briefly appears.
To have the beep sound again, press
F+BEEP again.
Press
to the VFO mode.
or PTT to store the setting and exit
670+0)"6*'"9'#6*'4"4#&+1"
5'66+0)"6*'"(4'37'0%;"56'2
Follow these steps to change the frequency
increment used during scanning and
stepping to a frequency.
(4'37'0%+'5
The transceiver can receive seven NOAA
(National Oceanographic and Atmospheric
Administration) weather broadcast
frequencies. To listen to the channel
broadcasting in your location, repeatedly
1. Press F+STEP. IJ;Fýand the current step
setting (in kHz) appear.
press
to select the weather band. MN
±"016'"±"
appears. Then rotate CH or repeatedly press
8
9
2. Repeatedly press
or
or CH until
•
•
•
•
When the transceiver receives no signal
8
9
or
to select your local weather
within an 8-second period, begins flashing
the desired new setting appears. You
can change the frequency step to 5 kHz,
6.25 kHz, 7.5 kHz, 10 kHz, 12.5 kHz, 15
kHz, 20 kHz, 25 kHz, or 50 kHz.
p
channel from the following table.
indicating power save is active.
When the transceiver receives a signal
%JCPPGN"0WODGT
(TGSWGPE["*/*\+
during the 8-second period, remains
p
steady.
162.400
162.425
162.450
162.475
162.500
162.525
162.550
9>#'
3. Press
or PTT to store your selection.
The green signal indicator lights to indicate
that a signal has been received and that
power save is on stand-by.
9>#(
9>#)
9>#*
9>#+
9>#,
9>#-
219'4"5#8'
To use the transceiver for packet
communications, disable power save (see
“Using the Transceiver with Packet Radio”
on Page 7).
Power save conserves battery power by
turning off power to the receiver part of the
transceiver and turning it on briefly every 8
seconds to check for a transmission.
To enable power save, press F+PS (5).
p
p
appears.
75+0)"6*'"5#/'"#.'46
To disable power save, press F+PS (5).
disappears. ±
Traditional weather radios simply receive the
NOAA weather broadcast (usually within a
40-mile radius), then sound an alarm if any
emergency code was transmitted along with
the broadcast. People who live outside an
affected area are often alerted even when
their area is not affected, causing many of
75+0)"#761"219'4"5*761((
Follow these steps to have the transceiver
automatically turn off after a preset period of
non-use.
8
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them to potentially ignore real weather
warnings that can save lives.
The transceiver displays one of the following
codes when it receives an alert signal.
M7HD for Warning
M7J9> for Watches
IJCJ for Statement
J;IJ for Test
In 1994, NOAA began broadcasting SAME
(Specific Area Message Encoding) codes
along with their standard weather broadcasts
from local stations in your area. SAME codes
identify the type of emergency and the
specific geographic area (such as a county)
affected by the emergency. Your transceiver
receives, interprets, and displays information
about the codes so you can determine if the
emergency might affect your area. Only
SAME-compatible radios (such as this
transceiver) are able to take advantage of
this new technology.
The weather alert operates only when the
transceiver is in weather mode. ±
'06'4+0)";174"#4'#N5"5#/'"
%1&'5
You can store up to nine SAME codes. Refer
to the SAME codes at http://
www.nws.noaa.gov/nwr/indexnw.htm. for the
corresponding codes for any specific area
you wish to monitor for weather warnings or
watches.
Each SAME code identifies a specific
geographic area (defined by the National
Weather Service [NWS]), so your transceiver
sounds an alert only when a weather
emergency is declared in that area. This
helps you more efficiently track the weather
conditions in and around your area.
±"016'"±"
Understanding SAME Codes
6
7
1. Repeatedly press
or
until 7H;7
appears. If no SAME codes are stored in
Most SAME codes begin with 0, which means
the code represents an entire county. The NWS
plans to eventually subdivide some large
counties. When that happens, each subdivision
will be assigned a digit from 1 through 9,
resulting in codes such as 148439, 248439, and
so on.
memory, _ _ _ _ _ _ and 7' appear.
8
9
2. Repeatedly press
or
to select the
70&'456#0&+0)"5#/'"%1&'5
For the purpose of broadcasting weather
information, the NWS divided the United
States into regions by state and county (or
parish, where applicable) then assigned a
six-digit SAME code to identify each county
or parish. For example, the code for Tarrant
County, Texas, is 048439.
desired memory location (A1–A9).
3. Enter your area’s SAME code using the
number keys.
Turning on the SAME Alert
If you want to enter another SAME code,
repeat Steps 2 and 3.
•
When the SAME code is detected, the audio
is muted.
4. Press
exit.
or PTT to store the code and
•
If you do not program any SAME codes into
the transceiver’s memory, the transceiver
detects all SAME signals when the SAME
function is on.
The first digit in a SAME code identifies the
county subdivision, the next two digits identify
the state, and the last three digits identify the
county or parish. ±
75+0)"6*'"'.'%6410+%"
Using the Electronic Compass
%1/2#55
•
The compass is not intended to be used as a
scientific instrument. The accuracy of the
compass is affected by environmental
factors in the area where the radio is being
used. 9E#;HH appears when the transceiver
does not detect compass data. If 9E#;HH
appears, repeat Steps 1–5 to re-calibrate the
compass.
Your transceiver has an electronic compass
that can display two digits of direction such
as SE or NW and up to three digits of
directional angle such as 360°, 180°, 90°, or
45° in five degree steps.
Your transceiver can receive all SAME alert
signals broadcast within about a 40-mile
radius. To receive SAME alerts and
broadcasts about weather occurring only in
particular counties within that area, you can
program up to nine SAME codes into the
transceiver’s memory (see “Entering Your
Area’s SAME Codes” on Page 9). For
You must calibrate the electronic compass
before using it.
•
To use the electronic compass feature, you
need to hold the transceiver within 30
degrees of a horizontal position.
example, this lets you avoid hearing an alert
that applies to an area within a 40-mile radius
but not necessarily to your county or parish.
1. Turn off the transceiver.
2. Place the transceiver horizontally on a
flat surface that does not give off
electrical or magnetic interference.
6740+0)"10"6*'"5#/'"#.'46
When your local weather station broadcasts
a weather alert signal, the transceiver sounds
an alert tone and displays an alert code for 5
seconds, showing the level of alert being
broadcast. Follow these steps to turn on the
alert.
3. Hold down COMP and press PWR.
4. Place your index finger on the side of the
transceiver’s antenna and turn the
transceiver clockwise or
counterclockwise, twice, smoothly and
continuously. Take 8 to 9 seconds to
complete a circle.
1. Repeatedly press
weather mode.
to select the
5. Press PTT or
. ±
6
7
2. Repeatedly press
appears.
or
until I7C;
To use the electronic compass press
F+COMP (H/L) to see the magnetic direction.
The display provides 8 primary directions; D,
D;, ;, I;, I, IM, M, and DM. If you press any
key, the compass display disappears. ±
8
9
3. Press
4. Press
or
to select ed.
appears.
r
or PTT to store the setting.
9
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5'.'%6+0)"6*'"64#05/+6"219'4
You can select one of the three transmitting
power levels: High (no display), Mid (C
appears), and Low (B appears). To select the
level, repeatedly press H/L.
4'%'+8+0)"6*'"#+4"$#0&
Repeatedly press
the airband at the top of the display. Press
until 7 appears to select
8
9
, or rotate CH to tune to the
or
frequency you want to hear. The air band
receiving range is 108 to 136.9875 MHz.
%4155"$#0&"%*#00'."
%*#0)+0)"6*'"64#05/+6"
12'4#6+10
(4'37'0%;"4#0)'
You can select a transmit frequency in the
VHF band and a receive frequency in UHF
band or vise versa. Or, you can select a
transmit frequency and a receive frequency
in the same band. ±
You can change the standard transmit
frequency ranges to extended ranges. ±
±"016'"±"
Cross Band Channel Operation
You cannot transmit and receive at the same
time.
Standard Transmit Frequency Ranges:
2 m: 144–148 MHz
1. Press F+XBO (SC). The main frequency
is duplicated at the sub frequency
Changing the Transmit Frequency
Range
70 cm: 438–450 MHz
display.
appears to the right of the
q
main frequency display.
The extended transmit frequency range feature
is only for MARS, CAP, and public service
users. Once you change the setting to the
extended ranges, be sure not to transmit on
those frequencies unless you are licensed to do
so.
Extended Transmit Frequency Range:
2 m: 142.000–149.880 MHz
70 cm: 420.000–470.000 MHz
2. Enter the transmit frequency on the main
frequency display.
3. Press F+REV (8) to exchange the main
frequency display and sub frequency
display.
To extend the range, turn off the transceiver.
Then while holding down SC+9, press PWR.
To return to the standard range, repeat the
above steps.
4. Enter the receive frequency on the main
frequency display.
5. Press PTT to transmit using cross band.
(%%"+0(14/#6+10
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 undesired operation.
To exit the cross band channel operation,
press F+XBO (SC).
&7#."9#6%*
You can set the transceiver to check a
specified channel every 2.5 seconds while
receiving any other channel. If the transceiver
finds a signal on the specified channel, it
automatically switches to it.
%#4'
Keep the transceiver dry; if it gets wet, wipe it
dry immediately. Use and store the
transceiver only in normal temperature
environments. Handle the transceiver
carefully; do not drop it. Keep the transceiver
away from dust and dirt, and wipe it with a
damp cloth occasionally to keep it looking
new.
1. Select a frequency you do not want to
miss while you receive another
frequency.
2. Press DW. The transceiver duplicates
the selected frequency on the sub
frequency display.
3. Select a frequency you want to receive
on the main frequency display.
'44"&+52.#;
The transceiver scans the channel on the sub
frequency display every 2.5 seconds.
If you use your transceiver in an area (such
as a vehicle) that has many metal surfaces,
the transmitted signal can reflect back into
the radio and cause the PLL circuit to unlock.
If this happens, ;HH appears. This is an
inherent problem with this type of transceiver.
If you press PTT, the transceiver transmits
the frequency on the sub frequency display
and the dual watch is canceled. If you want to
transmit the frequency on the main frequency
display, press F+REV to exchange the
frequencies.
To avoid this problem, you can try reducing
output power, use an external antenna, or
relocate the transceiver when ;HH appears. If
;HH appears even when you are using an
external antenna located away from the
transceiver, service might be required.
If you hold down M, the transceiver scans for
the frequency on the sub frequency display
until you release M.
10
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4'5'66+0)"6*'"64#05%'+8'4
If the transceiver’s display locks up or the
transceiver does not work properly after you
turn it on, you might need to reset it. .
5'48+%'"#0&"4'2#+4
If your transceiver is not performing as it
should, take it to your local RadioShack store
for assistance. Modifying or tampering with
the transceiver’s internal components can
cause a malfunction and might invalidate its
warranty and void your FCC authorization to
operate it.
."%#76+10".
This procedure clears all the information you
have programmed into the transceiver. Before
you reset the transceiver, try turning it off then on
again to see if it begins working properly.
To reset the transceiver, turn it off then hold
down F+6 and turn it on again. All the display
indicators appear to confirm the reset
operation. Release F+6.
52'%+(+%#6+105
GENERAL
Frequency:
2-Meter....................................................................................... TX: 144–148 MHz, RX: 137–174 MHz
70-cm......................................................................................... TX: 438–450 MHz, RX: 420–512 MHz
Air Band ............................................................................................................ 108.000-136.9875 MHz
Weather Band ................................................................................................................................ CH1–CH7
Frequency Generation .......................................................................................................... PLL Synthesizer
Frequency Stability .......................................................................................................................... ± 10 ppm
Operating Temperature..................................................................................... 14° to 140° F (–10° to 60° C)
Operating Voltage ................................................................................................................ DC 5 V to 13.8 V
Modulation ............................................................................................................................................... F3E
Impedance .......................................................................................................................................... 50 ohm
Dimension (HWD)................................................................................. 41/2 × 22/5 × 11/5 (122 × 61 × 31 mm)
Weight (w/rechargeable battery)............................................................................................ 11.46 oz (325g)
RECEIVER
Circuit Type............................................................................................. Dual Conversion, Superheterodyne
IF Frequency:
1st IF.......................................................................................................................................... 45 MHz
2nd IF........................................................................................................................................ 450 kHz
Sensitivity................................................................................................................... 0.2 µV For 12dB Sinad
Distortion.............................................................................................................................................5% Max
S/N Ratio........................................................................................................................................ 34 dB Min.
Audio Output @ 10% THD.................................................................................................. 300 mW at 8 ohm
TRANSMITTER
Power Output................................................................................................. 3 W, DC 7.2 V 4 W, DC 13.8 V
Distortion (nominal).................................................................................................................................... 3%
Deviation.................................................................................................................................... ± 5 kHz Max.
S/N Ratio................................................................................................................................................ 32 dB
Current Drain ............................................................................ 1200 mA, DC 7.2 V 1500 mA, DC 13.8 V ±
±"016'"±"
The software protocol and construction for a PC
interface cable is available in the 19-1108
Service Manual. You can order a service
manual through your local RadioShack store.
Specifications are typical; individual units might vary. Specifications are subject to change and improvement
without notice.
Limited One-Year Warranty
This product is warranted by RadioShack against manufacturing defects in material and workmanship under normal use for one (1) year from the date of purchase from RadioShack company-owned stores and au-
thorized RadioShack franchisees and dealers. EXCEPT AS PROVIDED HEREIN, RadioShack MAKES NO EXPRESS WARRANTIES AND ANY IMPLIED WARRANTIES, INCLUDING THOSE OF MERCHANT-
ABILITY AND FITNESS FOR A PARTICULAR PURPOSE, ARE LIMITED IN DURATION TO THE DURATION OF THE WRITTEN LIMITED WARRANTIES CONTAINED HEREIN. EXCEPT AS PROVIDED
HEREIN, RadioShack SHALL HAVE NO LIABILITY OR RESPONSIBILITY TO CUSTOMER OR ANY OTHER PERSON OR ENTITY WITH RESPECT TO ANY LIABILITY, LOSS OR DAMAGE CAUSED DI-
RECTLY OR INDIRECTLY BY USE OR PERFORMANCE OF THE PRODUCT OR ARISING OUT OF ANY BREACH OF THIS WARRANTY, INCLUDING, BUT NOT LIMITED TO, ANY DAMAGES RESULTING
FROM INCONVENIENCE, LOSS OF TIME, DATA, PROPERTY, REVENUE, OR PROFIT OR ANY INDIRECT, SPECIAL, INCIDENTAL, OR CONSEQUENTIAL DAMAGES, EVEN IF RadioShack HAS BEEN AD-
VISED OF THE POSSIBILITY OF SUCH DAMAGES.
Some states do not allow limitations on how long an implied warranty lasts or the exclusion or limitation of incidental or consequential damages, so the above limitations or exclusions may not apply to you.
In the event of a product defect during the warranty period, take the product and the RadioShack sales receipt as proof of purchase date to any RadioShack store. RadioShack will, at its option, unless otherwise
provided by law: (a) correct the defect by product repair without charge for parts and labor; (b) replace the product with one of the same or similar design; or (c) refund the purchase price. All replaced parts and
products, and products on which a refund is made, become the property of RadioShack. New or reconditioned parts and products may be used in the performance of warranty service. Repaired or replaced parts
and products are warranted for the remainder of the original warranty period. You will be charged for repair or replacement of the product made after the expiration of the warranty period.
This warranty does not cover: (a) damage or failure caused by or attributable to acts of God, abuse, accident, misuse, improper or abnormal usage, failure to follow instructions, improper installation or mainte-
nance, alteration, lightning or other incidence of excess voltage or current; (b) any repairs other than those provided by a RadioShack Authorized Service Facility; (c) consumables such as fuses or batteries; (d)
cosmetic damage; (e) transportation, shipping or insurance costs; or (f) costs of product removal, installation, set-up service adjustment or reinstallation.
This warranty gives you specific legal rights, and you may also have other rights which vary from state to state.
RadioShack Customer Relations, 200 Taylor Street, 6th Floor, Fort Worth, TX 76102
12/99
19-1108
RadioShack Corporation
Fort Worth, Texas 76102
04A02
Printed in China
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