HTX-100 Mobile Transceiver
(190-1101)                 Operation                  Faxback Doc. # 39456


This section describes how to turn on and set the operating controls of
your transceiver the first time.

1.  Set all the switches a shown.

2.  Turn the VOLUME control clockwise to turn on your transceiver.
    Set the volume at about the midpoint.

3.  Adjust the SQUELCH control counterclockwise until you hear a hissing
    sound.  Then, slowly rotate the control clockwise until the hissing

    Your transceiver is now ready to tune-in to the action.


Setting the Frequency Step

1.  Turn on your transceiver and select the SSB or CW mode by pressing
    MODE.  SSB or CW appears on the display to indicate the mode.

2.  Press [STEP].  The underline moves to the next digit.  This underline
    shows the digit that increments or decrements when you use the tuning
    knob or the UP and DOWN buttons.

    Press [STEP] a few more times.  Each time you press [STEP] the
    underline moves.

3.  Tune to a frequency using the tuning knob
    (see "Using the Tuning Control") or the UP and DOWN buttons
    (see "Using the UP and DOWN Buttons").

Using the Tuning Control

1.  Press [STEP] so that the underline is under the digit by which you
    want to increment or decrement.

2.  Turn the tuning control clockwise to increase the frequency.

3.  Turn the tuning control counterclockwise to decrease the frequency.


    If you are moving to a distant frequency, start with a large step.
    As you get closer reduce the stepping frequency.  For a very large
    jump, see "Using the 500K Button."


    When you reach either end of the frequency range, the transceiver
    "Wraps around" to the other end of the range.  So, if the frequency
    is 29.6999 and you increase the frequency by .001, the new frequency
    is 28.0009.

Using the UP and DOWN Buttons

Your transceiver has two sets of UP and DOWN buttons.  One set is on the
front of the transceiver and the other set is on your microphone.  Each
set operates in the same manner, so follow these instructions to use

1.  Press [STEP] to set the stepping frequency.

2.  Press UP to go up one frequency step or DOWN to go down one frequency
    step.  If you hold down either button longer than 1/2 second, your
    transceiver steps rapidly through the frequencies.

    Scanning Hint:

    If you are randomly scanning, trying to find someone that is
    transmitting, press and hold either button while watching the
    RF POWER/SIGNAL meter.  When you pass the active frequency, the
    indicators come on briefly.  Stop scanning, and manually step to
    the active frequency.

Fine-Tuning with RIT

RIT means Receiver Incremental Tuning.  This is just a fancy way of saying
fine-tuning.  The one difference in this control, is that this only
fine-tunes the receiver.  When you transmit, your transceiver uses the
exact frequency displayed.  Use this control if someone else's transmitter
is a little off-frequency.  Tune up or down with this control until the
incoming signal sounds the best.

Using the 500K Button

The [500K] button is handy if you need to get rapidly to the other end of
the band from where you are currently tuned.  Pressing [500K] causes the
frequency to increase by .5 MHz (500 kHz).


When you have established a conversation, or if you are monitoring
a conversation, you can increase or decrease the level of the signal
received by your transceiver.  If you are monitoring a nearby high-power
unit, the signal strength could cause the signal to distort.  Turn the
RF GAIN control counterclockwise to decrease the amount of RF gain and
make the signal more "readable."  If you are monitoring a low-powered,
distant unit, turn the RF GAIN control clockwise to increase the amount of
RF gain and boost the incoming signal.


When the F.LOCK/OUT switch is set to the F.LOCK position, you cannot
change the tuned frequency.  Use this to prevent accidentally changing the
frequency when you have tuned to an interesting or important broadcast.
Set the F.LOCK/OUT switch to OUT to allow you to change frequencies.


The NB/OUT switch allows you to turn on and off the noise-blanker circuit.
The noise-blanker circuit greatly reduces or eliminates noise generated by
automotive ignition, electrical motors, or other devices that might
generate spurious RF noise.  Normally, leave the NB/OUT switch set to NB.


Five LEDs function as an RF Power meter to indicate the relative
transmission output power in the transmission mode, and as a signal
strength meter to indicate the relative strength of the received signal
in the reception mode.


Remember, before you can transmit, you must have a FCC Amateur Radio
Operator's License.  Also, be sure you know your transmit privileges.

Transmission Power

Your transceiver has two power output levels - 5 watts and 25 watts.
Regulations require that you use the minimum power necessary to maintain
reliable communications.  As a rule, for local communications, pull out
the RF GAIN control.  This switches your transceiver to low power
(ham operators call this QRP - the Q-signal for reduced power).  If the
other party has trouble receiving your signal, push in the RF GAIN control
to switch to 25W.

Transmitting CW (Morse Code)

1.  Select a frequency.

2.  Press [MODE] so that CW appears in the display.

3.  Plug in the code key.

4.  Start keying.  Your transceiver automatically begins transmitting, and
    generates a CW tone each time you operate the key.  Your transceiver
    switches to receive one second after your last key press.


    See "Using TX/RX" for information on transmitting continuously.

Transmitting SSB (Voice)

1.  Select a frequency higher than 28.3000 MHz.

2.  Press [MODE] so that  SSB appears in the display.

3.  Press the push-to-talk button on the microphone to talk, and release
    the button to listen.

Using the TX/RX Switch

In most situations, just leave the TX/RX switch set to RX.  If, however,
you are sending a long CW message, it might be easier to send with the
transceiver constantly in the transmit mode.  To do this, simply set the
TX/RX switch to TX.  To listen for a reply, you must set the switch back
to RX.


Your transceiver has 10 memory channels you can use to store and recall
important frequencies.

Storing a Frequency in Memory

1.  Press [MEMORY], then UP or DOWN until the desired memory number (0-9)
    appears in the display.

2.  Select a frequency to store using the tuning control.

3.  Select a transmit mode (CW or SSB).

4.  Press [STORE] to store the frequency and mode in the memory.

Recalling a Frequency from Memory

1.  Press [MEMORY].  MEMO appears in the display.

2.  Press UP or DOWN until the desired memory appears.

3.  To return to normal tuning, press [MEMORY].



Several exciting operation modes are now available to the novice or
technician class amateur ratio operator.  These are packet radio and
several forms of RTTY (radio tele-type).  These modes let you send
information from your computer to other computers using your ham radio.
For more in-depth information concerning interfacing your computer to the
ham world, we recommend you read Digital Communications with Amateur
Radio, available at your local Radio Shack store.  The following
information is to help you use digital devices with your HTX-100.

Receive-to-Transmit Turnaround Time..................................40 ms

    1 - Microphone Input

    2 - Push-To-Talk*

    3 - Channel Down*

    4 - Channel Up*

    5 - 8 Volts (Power Indicator)

    6 - Audio Out

    7 - Microphone Ground

    8 - Ground

    *   Connect to Ground for function.


The following chart gives the latest information on the "gentlemen's
agreement" that ARRL members follow when using the 10-meter band.

Frequency                  Operating Mode Note

28.000 - 28.070            CW

28.070 - 28.150            RTTY

28.150 - 28.190            CW

28.100 - 28.200            CW        New Beacon Band*

28.200 - 28.300            CW        Old Beacon Band* Until 1990

28.300 - 29.300            Phone

29.300 - 29.510            Satellites

29.510 - 29.590            Repeater inputs

29.600                     FM simplex calling frequency

29.610 - 29.700            Repeater inputs

*Beacon bands are reserved for special stations.
 Do not transmit in these bands.


Your vehicle generates electrical noise that can cause interference on
your transceiver.  Since the receiver section of your transceiver is very
sensitive, it picks up even the smallest noise signals and amplifies them.
Any noise that you hear from the transceiver is almost totally from
external sources.  The receiver itself is exceptionally quiet.  If the
noise is continuous and fairly loud, it cannot be totally eliminated by
the automatic noise limiter circuit or the noise blanking circuit.
You must solve the problem at its source.  To find out if the noise is
from your ignition system, try this simple test.  Turn off your ignition
switch, then set it to ACC (accessory).  This turns off the ignition, but
supplies power to the transceiver.  The noise probably disappears,
suggesting that the source of the noise is your vehicle's ignition or
other electrical system.

You can identify ignition noise because it varies with the speed of the
engine.  Ignition noise consists of a series of popping sounds.  There are
many things that can be done to reduce this type of noise.

    Use only the radio suppression-type high-voltage ignition wire
    (spark-plug and coil cables).  Most new cars come equipped with this
    type of wire.

    Inspect the ignition wire and all connections.
    Old ignition wire can develop leaks, resulting in noise.

    If the noise persists, replace the spark plugs with types that have
    built-in suppressor resistors.  Be sure to use the correct type of
    spark plug for your vehicle.

Other sources of noise are:


    Voltage regulator


    Static Discharge

You can efficiently reduce or eliminate most of these noises by installing
bypass capacitors at the devices various voltage points.  Check your local
Radio Shack store for a selection of noise reduction accessories.


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