Heathkit SW-7800 - Page 22

Page
110
Heathkit
Sideband:
The
band
of
frequencies
on
each
side
of
the
transmitter
carrier
frequency
is
called
a
side-
band. The
upper
sideband
(USB)
is
the
band
of
fre-
quencies
created
by
the
SUM
of
the
carrier
and
mod-
ulating
frequencies.
The
lower
sideband
(LSB)
is
the
band
of
frequencies
created
by
the
DIFFERENCE
be-
tween
the
carrier
and
modulating
frequencies.
Single
Sideband
(SSB):
Single
sideband
is
not
new
Over
50
years
ago,
it
was
determined
that
a
single
sideband
contains
all
the elements
necessary
to
r
produce
the
original
modulation
signal
(intelli-
gence)
at
the
receiver.
At
the
present
time,
single
sideband
systems
are
generally
accepted
for long-
range,
point-to-point
communications.
Continuous
Wave
(CW):
This
is
a
process
of
trans
mitting
a
radio
frequency
in
Morse
code,
with
no
modulation.
In
this
case,
intelligence
is
produced
by
causing
the
radio
frequency
to
be
interrupted
a
discrete
intervals
to
produce
radiotelegraph
code
‘These
code
signals
are
made
audible
by
a
heterodyn
ing
process
within
the
receiver.
It
is
unlikely
that
these
short
explanations
have
adequately
covered
such
complex
terms.
There
are
however,
many
fine
books
that
treat
these
subjects
in
greater
detail.
Several
books
and
r
available
for
electronic
stands
and
libraries.
The
Radio
Amateur's
Ha
hobbyists
at
most
news
\dbook
by
the
American
Radio
Relay
League
(ARRL)
is
writ
ten
especially
with
the
needs
of
the amateur
in
mind