User's Manual

3. If the channel is clear, depress the push-to-talk switch on the microphone
and speak in a normal voice.
RECEIVING SSB SIGNALS
There are three types of signals presently used for communications in the
Citizens Band : AM, USB, LSB. When the MODE switch on your unit is
placed in the AM position, only standard double-sideband, full carrier
signals will be detected. An SSB signal may be recognized while in the AM
mode by its characteristic "Donald Duck" sound and the inability of the
detector to produce an intelligible output. The USB and LSB modes will
detect upper sideband and lower sideband respectively, and standard AM
signals.
SSB reception differs from standard AM reception in that SSB receiver does
not require a carrier or opposite sideband to produce an intelligible signal. A
single-sideband transmitted signal consists only of the upper or the lower
sideband and no carrier is transmitted. The elimination of the carrier from
the AM signal helps to eliminate the biggest cause of whistles and tones
heard on channels which make even moderately strong AM signals
unreadable. Also, SSB takes only half of an AM channel, therefore two SSB
conversations will fit into each channel, expanding the 40 AM channels to
80 SSB channels. The reduction in channel space required also helps in the
receiver because only half of the noise and interference can be received with
100% of the SSB signal.
An SSB signal may be received only when the listening receiver is
functioning in the same mode. In other words, an upper sideband signal
(USB) may be made intelligible only if the receiver is functioning in the
USB position.
If a lower sideband (LSB) signal is heard when the receiver is in the USB
mode, no amount of tuning will make the signal intelligible. The reason for
this may be understood if you consider that when the modulation is applied
to the transmitter's microphone in the USB mode, the transmitter output
frequency is increased whereas in the LSB mode the transmitter's output
frequency is decreased.
The result in listening to the receiver is that when the MODE switch is in the
proper position (either USB or LSB), a true reproduction of single tone of
modulation will result, and if the tone is increased in frequency (such as a
low-pitched whistle or a high-pitched whistle) you will hear the increase in
the output tone of the receiver. If the incorrect mode is selected, an increase
in tone of a whistle applied to the transmitter will cause a decrease in the
resultant tone from the receiver.
Thus when a voice is used in place of a whistle or tone, in the proper
listening mode the voice will be received correctly whereas in the incorrect
mode, the voice will be translated backwards and cannot be made intelligible
by the CLARIFY control. When listening to an AM transmission, a correct
sideband is heard in either mode since both upper and lower sideband are
received.
Once the desired SSB mode has been selected, frequency adjustment may be
necessary in order to make the incoming signal intelligible. The CLARIFY
control allows the operator to vary frequency above and below the exact-
center frequency of the received signal. If the sound of the incoming signal is
high or low pitched, adjust the operation of the CLARIFY.
Consider it as performing the same function as a phonograph speed control.
When the speed is set too high, voices will be high-pitched and if set too
low, voice will be low-pitched. Also, there is only one correct speed that will
make a particular record is played on a turntable that rotated in the wrong
direction (opposite sideband) no amount of speed control (CLARIFY) will
produce an intelligible sound.
An AM signal received while listening in one of the SSB modes will
produce a steady tone (carrier) in addition to the intelligence, unless the SSB
receiver is tuned to exactly the same frequency by the CLARIFY control.
For simplicity, it is recommended that the AM modes be used to listen to
AM signals.
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