RadioShack FM Mobile Transceiver HTX 252 Owners Manual

							21
2. Hold the microphone about 3 inches from your mouth.
3. Hold down the ribbed transmit button on the side of the
microphone, then speak slowly and clearly into the micro-
phone. appears while you transmit, and signal strength
bars appear on the bottom to indicate the relative transmit-
ting signal output.
Note: If you try to transmit outside the transmit frequency
range, 
E appears instead of   to indicate you are out-
side the transmitting range.
4. Release the transmit button
 when you finish transmitting.
TX
TX 
						

							22
UNDERSTANDING REPEATERS
Operating through a repeater, where you transmit on one fre-
quency and receive on another, is called 
duplex operation. Oper-
ating direct to another station, where you transmit and receive on
the same frequency, is called 
simplex operation.
A repeater is a station that receives a signal on one frequency
(the 
input frequency) and then retransmits that signal on a differ-
ent frequency (the 
output frequency). Repeater antennas are typ-
ically located at the tops of tall buildings or on antenna towers, so
a relatively low-power signal can reach the repeater. The repeat-
er retransmits the signal at a higher power. This gives your trans-
ceiver 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 fre-
quency. For example, 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 the 
offset direction (+ if you
add 600 kHz to the output, or – if you subtract 600 kHz from the
output).
Whether the offset is positive or negative depends on:
• which part of the band the repeater operates on
• local convention
• proximity of repeaters using the same two frequencies
To determine the offset and the direction, obtain a copy of 
The
ARRL Repeater Handbook
 (available at your local RadioShack
store or directly from the ARRL). That book lists the locations of
repeaters as well as their frequency and offset information.
A
  above the displayed frequency indicates a positive offset,
while a   above the frequency indicates a negative offset. If nei-
ther  nor appears, the transceiver is set for simplex opera-
tion. 
						

							23
SETTING THE REPEATER OFFSET 
FREQUENCY
Note: This setting affects only the VFO mode. If you saved a re-
peater offset in a memory, that setting is not affected.
1. Press 
F+SHIFT (LOCK). The offset frequency and   appear.
2. While the offset frequency appears, rotate the tuning control
or repeatedly press 
UP or DN until the desired offset
appears. The transceiver’s default repeater offset is 600
kHz, which appears as 
0.60 (MHz). You can select a
value from 100 kKz to 8.000 MHz.
3. Press 
PTT to store the setting or wait 5 seconds. The
selected value is stored and the operating frequency
appears.
SETTING THE REPEATER OFFSET 
DIRECTION
1. Set an offset frequency.
2. Repeatedly press 
F + SHIFT (LOCK) to change the current
offset direction (  above,  below, or 
neither for simplex or
non-repeater operation).
3. Press 
PTT to store the setting or wait 5-seconds. The
selected value is stored and the operating frequency
appears. 
						

							24
REVERSING THE TRANSMIT AND 
RECEIVE FREQUENCIES
To swap the input and output frequencies, press REV. For exam-
ple, if you have set the transceiver to repeater operation on
146.94 MHz with a positive offset of 600 kHz, the transceiver
would normally receive on 146.94 MHz and transmit on 147.54
MHz. After you press 
REV, the transceiver is set to receive on
147.54 MHz and transmit on 146.94 MHz. 
This feature is useful if you want to determine whether you are
close enough to another station to communicate on a simplex fre-
quency. While the other station is transmitting, reverse the fre-
quencies. If you can still hear the other station, you are hearing
their signal directly and you do not need to use the repeater. 
						

							25
MEMORY OPERATION
Your transceiver has 10 standard memory locations that you can
use to store frequencies for quick access. You can also store oth-
er settings for each memory location, such as the repeater offset
and the CTCSS tones.
STORING A TRANSMIT/RECEIVE 
FREQUENCY
1. Select the frequency you want to store by using the tuning
control or 
UP/DN. 
2. If desired, select an offset frequency, offset direction, and
CTCSS frequency for the selected frequency (see “Setting
the Repeater Offset Frequency” on Page 23 and “Continu-
ous Tone Coded Squelch System Features” on Page 28).
3. Press 
F+MS. A memory location appears and flashes if
empty. To select a different memory location, repeatedly
press 
UP/DN or rotate the tuning control.
4. Press 
MR. The transceiver stores the selected settings in
the memory location.
5. Press 
VFO to exit the memory mode.
RECALLING MEMORIES
1. Press MR so a memory location number appears.
2. Press 
UP or DN or rotate the tuning control to select the
desired memory location.
3. Press 
VFO to return to the VFO mode. 
						

							26
USING THE CALLING-FREQUENCY 
MEMORY
The calling-frequency memory location lets you quickly jump to a
specific programmed frequency at any time. The default calling
frequency is 146.52 MHz. You can store a different frequency into
memory as well as other settings associated with that frequency,
such as the repeater offset and CTCSS tone. 
1. Select the desired calling frequency using 
UP/DN or the tun-
ing control.
2. Press 
F+MR (MS). A memory location and ME appear.
3. Rotate the tuning control or repeatedly press 
UP or DN until
C appears in the memory location area on the display.
4. Press 
MR (MS). C flashes.
5. Press 
MR (MS) again to store the selected frequency.
6. Press 
VFO (T-SQ) to return to the VFO mode.
To enable the calling frequency, press 
CALL at any time. The
transceiver immediately tunes to that frequency with the settings
you programmed. To exit the calling frequency mode, press 
VFO
(T-SQ)
. 
						

							27
SCANNING OPERATION
SCANNING FOR ACTIVE FREQUENCIES
1. To search for activity on a frequency, press SCAN (PRI).
SCAN appears. The transceiver begins to scan up or down
the full frequency range. The transceiver stops on each
active frequency for 5 seconds if squelch is on. If squelch is
off, the transceiver stops on each location for about 1 sec-
ond.
2. To change the scanning direction, press 
UP or DN.
3. To stop on a frequency or to stop scanning completely,
press 
SCAN again.
SCANNING STANDARD MEMORY 
LOCATIONS
1. Press MS (MR) then SCAN. The transceiver scans all mem-
ory locations except empty locations.
2. To change the scanning direction, press 
UP or DN.
3. To stop scanning, press 
SCAN again. 
						

							28
CONTINUOUS TONE CODED 
SQUELCH SYSTEM FEATURES
Your transceiver can transmit and receive a low-level, selectable
subaudible tone at the same time as it transmits (TX) or receives
(RX) a regular signal. This special tone lets you listen only to oth-
er transceivers set to the same tone frequency when you use the
transceiver in simplex operation. It also lets you match your trans-
ceiver to the subaudible tone frequency used by a local repeater. 
To enable the TX and RX tones for the transceiver, follow these
steps.
1. Press 
F+T-SQ. The current tone setting and T appear. (T
indicates that only the TX tone is enabled.)
2. Rotate the tuning control or repeatedly press 
UP or DN to
select a tone frequency from the list on Page 28. About 5
seconds after your last change, the display exits the tone
setting mode, stores your tone selection, and the current
operating frequency appears again.
3. To enable both the TX and RX tones, repeatedly press 
F+T-
SQ
 until T-SQ appears. To disable CTCSS operation,
repeatedly press 
F+T-SQ until T and T-SQ disappear.
4. Press 
PTT to store all the settings.
TEMPORARILY OPENING SQUELCH
If you use the Tone Squelch (CTCSS) feature, 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 
F. To resume normal operation, release F. 
						

							29
Subaudible Tone Frequencies (Hz)
67.0 107.2 167.9
71.9 110.9 173.8
74.4 114.8 179.9
77.0 118.8 186.2
79.7 123.0 192.8
82.5 127.3 203.5
85.4 131.8 210.7
88.5 136.5 218.1
91.5 141.3 225.7
94.8 146.2 233.6
97.4 151.4 241.8
100.0 156.7 250.3
103.5 162.2 
						

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USING DTMF TONES
DTMF (Dual-Tone, Multiple Frequency) is another term for touch-
tones
 (the tones a telephone produces when you press a digit).
This standard set of tones is used by many different amateur
transceiver systems for accessing programmable features and
dialing through autopatches to a standard telephone.
Your transceiver produces all 16 standard DTMF tones (0–9,
*, #,
A, B, C, and D). 
Follow these steps to use the DTMF feature.
1. Set 
DTMF on the bottom of the microphone to 
ON.
2. Enter the DTMF sequence using the alphanumeric keys.
3. After you complete your transmission, set 
DTMF to the left
position to turn off the feature.