Heathkit SB-1000 - Page 57

Heathkit
120 VAC AND 240 VAC WIRING
The following information is presented in the event
you wish to change from 120 to 240 VAC or 240 VAC
to 120 VAC at some future time.
Changing from 120 VAC to 240 VAC
Refer to Pictorial 9-1 while you perform the follow-
ing steps.
() Unplug the Amplifier's line cord from the AC
outlet and remove the top cover. Be sure to
allow plenty of time for the high voltage to
completely discharge before you proceed.
NOTE: You can use the front panel multimeter
(in High Voltage position) to check the volt-
age.
() Locate the black stranded wire that is connect-
ed between terminal strip RE lugs 1 and 2. Then
cut off and discard this wire.
() Remove the two large black stranded wires
from barrier strip RD lugs 2 and 3 and lugs 4 and
5.
() Connect one of the black wires removed in the
above step between barrier strip RD lugs 3 and
4,
() Change fuses F1 and F2 to 10-ampere fuses.
Changing from 240 VAC to 120 VAC
Refer to Pictorial 9-2 while you perform the
following steps.
(.) Unplug the Amplifier's line cord from the AC
outlet and remove the top cover. Be sure to allow
plenty of time for the high voltage to completely
discharge before you proceed. NOTE: You can use the
front panel multimeter (in High Voltage position) to
check the voltage.
() Connect and solder a suitable length of medium
black stranded wire between terminal strip RE lugs 1
and 2,
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() Remove the black stranded wire from barrier
strip RD lugs 3 and 4.
© Connect a suitable length of large black strand-
ed wire between barrier strip RD lugs 2 and 3.
() Connect a suitable length of large black strand-
ed wire between barrier strip RD lugs 4 and 5.
() Change fuses Fl and F2 to 15-ampere fuses.
ANTENNA
The output circuit of the Amplifier is designed to be
connected to an unbalanced transmission line that
has a 50-ohm characteristic impedance. Lines of o-
ther characteristic impedance may be used, provi-
ding the SWR (standing-wave radio) does not ex-
ceed 2:1. In addition, the built-in wattmeter is only
accurate at 50 ohms.
The RF OUT connector is a UHF type SO-239. You
will need a mating PL-259 plug for your transmission
line. Refer to Pictorial 9-3, if necessary, to install
this plug.
Use coaxial cables like RG-8/U, RG-11/U, or similar
types, for the transmission line. Due to the power
level, the smaller types RG-58/U and RG-59/U are
not recommended.
The "A.R.R.L. Antenna Book" is readily available
and includes comprehensive reference work on trans-
mission lines and antennas. Other similar hand-
books for the radio amateur are offered for sale and
can often be found in a public library.
GROUNDING
Connect a good earth or water pipe ground to the
ground post on the rear panel of the Amplifier. Use
the heaviest and shortest connection possible.
Before you use a water pipe ground, inspect the
connections around your water meter and make sure
that no plastic or rubber hose connections are used.
These connections interrupt electrical continuity to
the water supply line. Install a jumper around any
insulating water connectors you may find. Use heavy
copper wire and pipe clamps. It is best to ground all
equipment to one point at the operating position and
then ground this point as described above.