MFJ MFJ-8100, Инструкция по эксплуатации, Страница: 12 / 27

MFJ-8100
World Band Receiver
12
On modern ham radio transceivers, tuning SSB is made so easy
by means of internal filters that many licensed ham operators
are not aware of the basic technique for tuning in SSB
signals on receivers without such filters.
The first fact to know about any given group of SSB signals
is whether they are Upper (USB) or Lower (LSB) Sideband. In
ham radio communication, LSB is used on 1.8 through 7.3 MHz,
and USB is used for all higher frequency bands (14, 18, 21,
28 MHz.)
The best band to practice SSB tuning with your receiver is
the "75 Meter'' band, 3.8 to 4.0 MHz, doing so in the evening
when the signals are strong and plentiful. Notice that the
band is spread out on the dial more than are the other
amateur bands, which permits easier tuning. These are all
LSB, lower sideband signals.
Think to yourself: for LOWER sideband, tune DOWN. for UPPER
sideband, tune UP.
In practice, this means that you would "approach'' the LSB
signal by tuning from higher frequency (right) to lower
(left), from higher voice pitch to lower pitch. Here's how
to do it step by step:
1. Pick out a strong, high-pitched Donald Duck voice.
2. Turn the tuning knob ever so slightly to the left.
3. If the pitch of the voice went DOWN slightly, you're
heading in the right direction.
4. SLOWLY tune left slightly more until the voice is clear.
Reverse this process to tune to UP (to the right) to USB
signals on the bands above 7 MHz.
The Regeneration Control often can be used to do the last
touch of fine tuning to bring the voice in clearly. If
signals are exceptionally strong, it may be necessary to
reduce the RF gain level (rear panel).
SSB transmissions are used by embassies and agencies of
various governments, so you might find interesting voice
signals on other than ham frequencies. Check with a
Shortwave Listener (SWL) or listings in Popular
Communications Magazine for more details.