TRC-490 AM/SSB CB Transceiver
(210-1583)           Controls and Functions           Faxback Doc. # 46653

This short description of the function of each control and jack supplies
background information for proper operation.  For actual Operating
Instructions, refer to "Using Your Transceiver" in Faxback Doc. # 46654.

          MICrophone - The dynamic microphone must be connected to this
                       jack.  To Transmit, press the button on the mic and
                       talk into the mic.  To Receive, release the button.
                       When transmitting, hold the microphone at an angle,
                       two or three inches (5-7.5 cm) from your mouth and
                       speak clearly in a normal voice.  Your Transceiver
                       features a new locking type microphone connector.
                       This insures that you won't accidentally pull out
                       or loosen the plug connection (when extending the
                       MIC cable while moving about).  To release the MIC
                       connector, you must press the small Tab on the Top
                       and then pull out.

              PHONES - Plug in communications type headphones for private
                       listening, or in areas where background noise is
                       excessive (factories, at the scene of an accident
                       or fire, etc.).  When you plug in the headphones,
                       it automatically disconnects the internal speaker
                       (or an external speaker).

    Channel Selector - Use to select any one of the standard 40 CB
                       channels.

VOLUME with "ON/OFF" - Turn clockwise to apply power to the unit and then
              switch   adjust for the desired level of sound from the
                       speaker.  When using PA, it controls the level of
                       the PA output.

             SQUELCH - Sets the level of the internal Squelch circuitry to
                       cut out the background noise when no signal is
                       being received.  When properly set, it allows
                       signals to come through, but cuts off the receiver
                       sound when no signal is being received, thus
                       eliminating annoying background/atmospheric noise
                       during standby and monitoring conditions.

                       If set too high, you may miss some of the weaker
                       signals.  Operating conditions will determine the
                       best setting.

             RF GAIN - Varies the sensitivity of the RF amplifier stages
                       of the Receiver circuitry.  For normal operation,
                       set RF GAIN to maximum and adjust VOLUME for a
                       suitable listening level.  Under high-signal
                       conditions, you may want to turn RF GAIN down a
                       little and raise VOLUME as required.

           CLARIFIER - Functions as a "fine tuning" (or "delta" tuning)
                       for reception of Single Side Band and AM signals
                       when the Mode switch is set to either LSB or USB.
                       This permits you to tune your receiver to exactly
                       the same frequency of any other station or stations
                       which you are communicating with.

     AM-USB-LSB Mode - Set this switch to the desired mode of operation
              Switch   for both transmit and receive.  When in the AM
                       position, both transmitter and receiver sections
                       are operative for AM.  When set to the LSB
                       position, the Receiver operates to receive only the
                       Lower Side Band portion of a signal; the Receiver
                       operates only to receive the Upper Side Band
                       portion of a signal; the Transmitter will transmit
                       only the Upper Side Band of the modulated waveform.

      PA push-button - Controls the function of the audio amplifier/
                       modulation circuitry when the Microphone button is
                       pressed.  When the PA button is in the "out"
                       position, the Microphone button turns the
                       Transmitter on for normal transmissions.  When you
                       press the button in, the Transmitter will not
                       function - the Microphone turns on the Public
                       Address Amplifier function.  For PA operation you
                       must have a PA speaker connected to the PA jack on
                       the rear chassis.

  ANL/NB push button - Press in to cut out annoying hash-type and impulse
                       type noises.  Press again to release this function.
                       NB (Noise Blanker) is particularly effective for
                       ignition noise on both AM and SSB, while ANL
                       (Automatic Noise Limiter) is effective for AM
                       signals.

          RF-S Meter - Gives visual indication of signal strengths.  When
                       receiving, the RF-S Meter shows the strength of
                       incoming signals; a change of one "S" unit
                       indicates a change of 6 dB in signal strength.  The
                       meter is set up so that a 100 microvolt signal will
                       produce a reading of S-9.  When Transmitting, the
                       RF-S meter gives a relative indication of output
                       power from the Transmitter.

PA + CB RECEIVE push - Press in both ANL/NB and PA to activate PA
              button   operation plus CB RECEIVE function; you can monitor
                       the CB signal from your PA speaker when the
                       microphone button is released.

         CH 9 Switch - Press in and you instantly jump to channel 9.
                       Press again to release this function and
                       Transceiver will return to the previously selected
                       channel.

 Channel 9 Indicator - Lights up when you are using the "instant" Channel
                 LED   9 function.

THE REAR PANEL:

     PA SPeaKeR Jack - Connect an 8 Ohm Public Address speaker to this
                       jack for PA use.  We recommend RadioShack's
                       40-1244, weatherized, rugged PA Speaker, as an
                       ideal unit for either PA or External Speaker
                       application.

External SPeaKeR Jack- If you want to use an external speaker, plug it
                       into this jack.  You should use a standard 8 Ohm
                       type.  When a miniature (9/64", 3.5 mm) phone plug
                       is inserted into this jack, the built-in speaker is
                       automatically disconnected.

        ANTENNA Coax - Connect your CB antenna to this (SO-239 type,
           Connector   accepts PL-259 connectors).

                FUSE - Is for protection of the Transceiver and its source
                       of AC power.  If the Transceiver does not operate
                       from AC power, check this fuse - replace only with
                       the same type and value (4 amp).

  13.8V DC Connector - This cable is to be connected to a source of 12-16
     and Power Cable   volts DC power, negative or positive ground.  The
   with in line fuse   Red wire with the in-line fuse must be connected to
                       the (+) side and the Black wire to the (-) side.

  120V AC POWER CORD - Plug into a source of 120 volts, 60 Hz AC power.

        DC-AC Switch - Selects the power source, DC or AC.

(BR/eb 10/12/98)

Privacy Policy