GME Electrophone TX4200 Series, Instruction Manual

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The UHF Citizens Band Radio Service (CBRS)
was set up to provide a simple yet reliable form
of radio communication for business, farming or
private use. A CB radio license is not required.
Your TX4200 operates in the UHF (Ultra High
Frequency) 477 MHz band and offers a much
higher quality service than 26/27 MHz systems.
In addition, by using FM (frequency modulation),
voice quality is improved while electrical
interference is virtually eliminated.
The range of a UHF FM signal is usually
considered ‘line-of-sight’, but this can be greatly
increased by the liberal use of repeaters.
Repeaters are special transceivers (transmitter/
receivers) installed in high locations. Their job
is to automatically re-transmit any signals they
receive, thereby extending the range of the
original signal. Generally, the range of your
UHF radio will vary according to your location
and the height of your antenna. UHF signals
are easily blocked by hills or large buildings, so
you wont get as much range in a valley or built-
up city area as you will from a hill or in open
country. If you are having trouble contacting
someone, try moving to an open space or a
higher location. Typical vehicle to vehicle range
is around 3 to 10 km depending on the terrain.
A base station, because of it’s higher antenna
installation, could extend it’s range to 30 km or
more depending on it’s location. Once again,
the use of repeaters can increase these ranges
considerably (up to 100 km or so).
The following functions are standard on most
UHF CB radios. Here is what they do.
Volume :
Used to adjust the level of sound
output from the speaker.
Squelch (sometimes called ‘Mute’) :
The
squelch control is used to eliminate any
annoying background noise when there are no
signals present. When the control is fully
counter-clockwise, the squelch is set to
minimum and everything can be heard in the
speaker. As the control is slowly advanced
clockwise, the squelch level increases until it
reaches a point where the background noise
suddenly disappears. This is known as the
threshold. At this point, the radio is quiet when
there are no signals being received, but any
incoming signals will overcome the squelch and
be heard in the speaker. As the squelch control
is advanced further clockwise, the squelch level
is progressively increased and stronger
incoming signals are needed to overcome it.
The usual procedure for setting the squelch is
to temporarily select an unused channel, adjust
the squelch control fully counter-clockwise, then
slowly advance it clockwise just past the point
where the background noise disappears.
Channels :
There are 40 frequencies available
in the UHF CB band. To make it easier to
identify each frequency, they are allocated
channel numbers (channels 1 to 40). The
channels are selected by rotating the channel
knob. The selected channel number appears on
the display.
Duplex :
UHF radios have a simplex/duplex
function. The
Simplex
mode is used when you
wish to talk directly to another radio. It allows
the radio to transmit on the same channel as it
receives. The
Duplex
mode is used when
communicating through repeaters. It causes the
radio to transmit and receive on two different
channels. Put simply, if you wish to talk directly
to another radio select ‘Simplex’. To talk to
another radio via a repeater, select ‘Duplex’.
Push To Talk (PTT) Switch :
This is the large
button on the side of the microphone. It is used
to make the radio transmit. To transmit, hold the
microphone close to your mouth, press the PTT
switch, then talk into the microphone in a normal
voice. When you have finished talking, release
the PTT switch and the radio will return to the
receive mode.
Scan :
The scan function allows you to listen for
signals on a number of channels in quick
succession. The radio monitors each channel
for just long enough to check for signals. If no
signals are present, it switches to the next
channel in sequence. If a signal is heard, the
radio pauses on that channel so the signal can
be heard. After the signal disappears, the radio
resumes scanning. The TX4200 scans at up to
10 channels per second and allows
you
to
select which channels you wish to scan.
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INTRODUCTION