SP-6/ SP-2000/ SP-220/ SP-7000
SUPER
AMP
GaAsFET
SERIES
50,144,220
& 432/435 MHz.
Mast-Mounted Preamplifiers
Thank
you for
purchasing
this
preamplifier
which
is
manufactured
by
SSB
ELECTRONIC
GmbH.
'Ve
believe
that
it
is
without a
doubt
the best available
anywhere
aDd would ask
that
you please spend a few
moments
10
read
through
these notes
in
order
to
ensure
that
you
obtain
the
very best possible results
from tbis
product.
The
full potential
of
this
preamplifier
can only be realized when a
minimum
of
feed line exists between
the
preamplifier
input
and
the
antenna
feed point.
Maximum
lengths are:
24
flo
on SO/144MHz
and
IS ft. on
432MHz
assuming
that
a
quality
coax. such as
AIRCOM
PLUS
is
used.
This
length can
usually
be
achieved
by
mounting
the
preamplifier
on the
support
mast
close to
the
antenna
mounting
point.
The
amplification factor
of
this
preamplifier
can be
adjusted
so
that
a good system gain distribution can
be
maintained.
This
is
important
in
order
to
insure
that
the receiver front-end as well as
tbe
mixer
are
not overloaded.
The
following table may
be
used as a guide
for
setting
the
preamplifier
gain to overcome
the
feedline losses
encountered
from
your
rig to
the
preamp.
'-
CABLE
LOSSES
Under
2 dB
2 - 3
dB
Over 3
dB
GAIN
SETTING
M1N
MID
M~,\(
The
following table may be used as a guide to
the
losses for
various
cable
types:
Frequencv
144 MHz.
432
MHz
RG58V
0.2 dB/M
0.4 dB/M
RG213
0.08
dB/m
0.15
dB/m
AIRCOM
PLUS
0.05 dB/M
0.08 dB/M
A good
rule
oftbumb
is to
aim
for
12
-14
dB.
of
gain above feed line losses.
Access to
the
gain
adjusting
potentiometer
is
obtained
by removing
the
four
self
tapping
screws from
the
underside
of
the unit.
This
enables the plastic
weather
shield to
be
removed
exposing
the
tin plated
shielded box in which a small hole will be found.
Adjustment
may
now
be
made
with a small
screw·
driver.
CAUTION:
Great
care
should
be taken when
making
this
adjustment
noting:
a)
The
potentiometer
only
rotates
through
270 deg.
b)
Do
not
exert
any
pressure
on the
adjuster
c)
Ensure
the
screwdriver
goes to
the
pot,
and
does
not
slip sideways
causing
possible
damage
to
any
surrounding
components. An insulated
trimming
tool would be
best
suited
for this job!
If
the tin plate box lid
is
removed to
make
this
adjustment
then please DO
NOT
TOUCH
ANY
OTHER
CONTROLS as these have all been carefully set at
the
factory for
the
best noise figure.
124 Cherrywood Drive., Mountaintop, Pa. 18707
(570)-868-5643
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