Heathkit SB-201 - Installation Guidelines

Page 44
Ge guestHxit:
INSTALLATION
LOCATION
Although the Linear Amplifier has a built-in fan for
cooling purposes, avoid excessively warm locations
such as those near radiators and heating vents. The
unit should be placed in a location that provides
adequate space around it, permitting free air circula-
tion through the cabinet openings.
POWER SOURCE
The Linear Amplifier is designed to operate from
either a 120 volt or 240 volt AC, 60 Hertz power
source, depending on the jumper installation on ter-
minal strip S. The AC power outlet used should be
properly fused and fed with not smaller than #14
wire.
The plug on the power cord for this kit is for standard
120 VAC outlets. For 240 VAC operation in the U.S.A.
cut off this plug and replace it with a permanent plug
that matches your 240 VAC receptacle. Be sure your
power connection conforms with section 210-21 (b) of
the National Electric Code, which reads in part:
“Receptacles connected to circuits having
different voltages, frequencies or types of
current (AC or DC) on the same premises shall be
of such design that attachment plugs used on
such circuits are not interchangeable.”
When you install a new plug, make sure it is con-
nected according to your local electrical code. Keep
in mind that the green line cord wire is connected to
the amplifier chassis.
EXCITER
The Linear Amplifier can be driven by most commer-
cial or home-built exciters with a power output of
approximately 100 watts. The Heathkit SB-400 or
SB-401 Transmitter or the SB-100, SB-101, SB-102, or
SB-104 Transceiver is ideal for use with this Linear
Amplifier.
Exciters in the 40 to 60 watt output class wil] not drive
the Linear Amplifier to a full kilowatt, however, the
Linear Amplifier will operate quite efficiently at
lower power levels.
ANTENNA
The pi-network output is designed to work into a 50 to
75 transmission line. Most commercial and home-
built antennas are designed to be fed with 50 or 720
coax. RG-8/U or RG-11/U coaxial cable is recom-
mended for the transmission line, and every effort
should be made to get the SWR of the antenna down to
less than 2 to 1.
SWR MEASUREMENTS
nee Connect the amplifier to the exciter and the
antenna. Do not turn the Linear Amplifier ON,
thus permitting the exciter to feed through the
; Linear Amplifier to the antenna.
( vi
Place the Linear Amplifier Meter switch in the
REL PWR position.
( v4 Load the exciter to full output. The meter of the
Linear Amplifier may be used for this purpose,
as it will function in both the REL PWR and
SWR positions without the Linear Amplifier
, being turned ON.
(“) Adjust the REL PWR SENS control of the Linear
plifier for a SET (full-scale) indication on
he meter.
( Turn the meter switch to SWR and read the
standing wave ratio directly from the meter (1 to
3 scale).
NOTE: SWR checks can also be made with the Linear
Amplifier operating at full power (1000 watts); how-
ever, due to the nonlinear characteristics of crystal
diodes in the SWR circuit, the most accurate SWR
readings are obtained at low power (70 to 100 watts)
levels using only the exciter. If the exciter alone will
not give full scale relative power readings, the Linear
Amplifier may be used. However, limit the drive from
the exciter to no more than necessary.