HTX-400 Mini Handheld 70-Centimeter FM Amateur Transceiver
(190-1104)                 Operation I                Faxback Doc. # 61415

Turning On The HTX-400

To turn on the HTX-400, rotate VOL/OFF clockwise until it clicks.  The 
HTX-400 sounds a brief melody if the key tone feature is enabled.  Then 
HELLO appears for about 2 seconds and the last used frequency appears.

Selecting Frequencies (Direct Tuning)

You tune to the desired frequencies in the VFO (variable frequency 
oscillator) mode.  You can either step to a specific frequency or directly 
select the frequency.

To step to a frequency, repeatedly press or hold down /\ or \/ until the 
display shows the desired frequency.

Note: The HTX-400 steps up or down in increments which you set using the 
      Frequency Step menu option.  (See "Setting the Frequency Step" in
      Faxback Doc. # 61417).

To directly enter a frequency, press FUNC + /\ (the second digit from the
left flashes), then press \/ or /\ to change the number.  Press FUNC + /\ 
again to select the next digit.  Repeat this to select each number of the
desired frequency, then press PTT to store the selection.

Note: The HTX-400 is preset to receive frequencies between 420 and 470
      MHz, and transmit between 430 and 450 MHz.  To expand the frequency
      coverage, see "Changing the Transmit Frequency Range" in Faxback
      Doc. # 61417.

Receiving Transmissions

Follow these steps to receive standard transmissions.

1.  With the radio 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 HTX-400 receives a standard transmission
           or if the squelch is open. If the transmission uses CTCSS tones
           CALL also appears.

           Volume, power, and squelch are combined in one control.  The
           inner control is VOL (volume) and power on/off, while the outer
           control is SQ (squelch).

           If the HTX-400 picks up unwanted, weak transmissions, 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 transmissions.

2.  Set VOL/OFF to a comfortable listening level. 

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 MO.  To resume 
normal operation, release MO.

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 transmit and another to receive.  For more 
information about duplex, see "Understanding Repeaters" below.

CAUTION:  It is illegal to transmit if you do not have at least a
          Technician Class license issued by the FCC.

Follow these steps to transmit.

1.  Select the desired frequency using manual or direct entry.

2.  Hold the HTX-400 about 3 inches from your mouth.

3.  Hold down PTT, then speak slowly and clearly into the microphone.  TX 
    appears while you transmit.

    Note: If you try to transmit outside the transmit frequency range,
          inhibit briefly appears.

4.  Release PTT when you finish transmitting.

Understanding Repeaters

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 a signal on one frequency (the input 
frequency) and then 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.

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 442.200 is referred to as 
"the 442.2 repeater."  To determine the input frequency, you must know the 
frequency offset (typically 5 MHz for the 70 cm-meter band) and the offset 
direction ((+) if you add 5 MHz to the output or (-) if you subtract 5 MHz 
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 from your local RadioShack store or directly 
from the ARRL) which 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 neither (+) nor 
(-) appears, the HTX-400 is set for simplex operation.

Setting The Repeater Offset Frequency

The HTX-400's default repeater offset is 5 MHz, which appears as 5.0 (MHz)
Follow these steps to change the offset.

Note: This setting only affects the VFO mode.  If you saved a frequency
      offset in a memory, that setting is not affected.

1.  With power off, hold down FUNC and turn on the HTX-400 mode.

2.  Hold down FUNC and repeatedly press \/ until rpt and the current
    offset appear.  0.0 appears if no offset is currently set.

3.  Repeatedly press \/ or /\ until the desired offset appears.  You can 
    set an offset between 0 and 8 MHz in 100 kHz steps.  

4.  Press PTT to store the setting and exit the menu.

Turning Duplex Operation On And Off

To turn on duplex (repeater use) operation for the VFO mode, press FUNC + 
SC (RPT).  Provided the current repeater offset value is not 0.0, the 
current offset indicator ((+) above or (-) below) appears above the 
displayed frequency.  Press FUNC + SC (RPT) again to turn it off.

Setting The Repeater Offset Direction

1.  Set an offset frequency other than 0.0.

2.  Press FUNC + SC (RPT) to see the current offset direction ((+) above
    or (-) below).

3.  Press FUNC + MO (REV) to change the repeater offset direction.

Note: To save this setting in a memory location, MR must be flashing 
      before you store the settings (see "Using the Calling-Frequency
      Memory" and "Storing a Transmit/Receive Frequency" below).
      Otherwise, the setting reverts to its saved value the next time
      you turn on the HTX-400.

Reversing The Transmit And Receive Frequencies

To swap the input and output frequencies, press FUNC + PTT. For example, 
if you have set the radio to repeater operation on 442.200 with a positive 
offset the radio would normally receive on 442.200 and transmit on 447.200 
MHz.  After you press FUNC + PTT, the radio will receive on 447.200 and 
transmit on 442.200.

This feature is useful if you want to determine whether you are close 
enough to another station to communicate on a simplex frequency.  While 
the other station is transmitting, reverse the frequencies.  If you can 
still hear the other station, you are hearing their signal directly and 
you do not need to use the repeater.

Memory Operation

Your HTX-400 has 30 standard memory locations that you can use to store 
frequencies for quick access. For each memory location, you can also store 
other settings such as the repeater offset, CTCSS tones, and frequencies 
to pass or lock out during scanning.

Storing A Transmit/Receive Frequency

1.  Press MR.  [MR] and the last used memory location appear. 

2.  Repeatedly press /\ or \/ to select the desired memory location.
    ---- appears if the memory location is empty.

3.  Press FUNC + MR.  The selected memory location and [MR] flash.

4.  Select the desired frequency by repeatedly pressing /\ or \/, or use
    direct frequency entry to select a frequency. 

5.  To enter a frequency offset for repeater operation, press FUNC + SC.
    The HTX-400 displays the current offset for the calling frequency.
    Then press /\ or \/ to select the desired offset. Press PTT to store 
    your setting.

6.  Press FUNC + REV to select the offset direction (+ or -).  To remove
    an offset for simplex operation, set the repeater offset to 0.0.

7.  If desired, set the tone squelch settings (see "Continuous Tone Coded 
    Squelch System Features" in Faxback Doc. # 61416).

8.  Press PTT to store all settings, then press MR to exit the memory mode

Recalling Memories

To recall saved memory settings, press MR so [MR] appears.  Then press /\ 
or \/ to select the desired memory location.

Press MR again to return to the VFO mode, (See "Selecting Frequencies 
(Direct Tuning)" above.)

Clearing A Single Memory

Follow these steps to clear any single memory location.

1.  Press MR.  [MR] and the last used memory location appear.

2.  Repeatedly press /\ or \/ to select the desired memory location.

3.  Press FUNC + MR.  The selected memory location and [MR] flash.

4.  Hold down FUNC for several seconds.  The memory location clears and
    ---- appears to confirm that the location is empty.

5.  Press MR to exit the memory mode.

Note: To clear all memory locations, see "Resetting the HTX-400" in 
Faxback Doc. # 61419.

Using The Calling-Frequency Memory

The calling-frequency memory location lets you quickly jump to a specific 
frequency at any time.  The default calling frequency is 446.0000 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.  Press C to display the current calling frequency.

2.  To change the frequency, hold down C until [MR] and C flash.

3.  Select a frequency. See "Selecting Frequencies (Direct Tuning)" above.

4.  Press C to store the selected frequency in memory.

5.  To enter a frequency offset for repeater operation, press FUNC + SC.
    The HTX-400 displays the current offset for the calling frequency.  To
    select a new offset value, press /\ or \/.  Select 0.0 Hz if you want
    to remove the offset.  To store the setting, press PTT.

6.  To select the offset direction (+ or -), press FUNC + REV.  To remove
    an offset for simplex operation, set the repeater offset to 0.0.

    Note: While [MR] and C appear, you can program other settings such as
          CTCSS tones (see "Continuous Tone Coded Squelch System Features"
          in Faxback Doc. # 61413.)

To enable the calling frequency, press C at any time.  The transceiver 
immediately tunes to that frequency with the settings you programmed. To 
exit the calling frequency mode, press C again.

(BR EB 8/30/00)

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