Tandy Color Computer 3 Manual page 19

Installation
If
you have a
75-Ohm
Coaxial Lead-in
and
a
Matching
Transformer, connect
the short twin-lead
from
the transformer
to
the
screw
terminals
on
the
Antenna Switchbox
(see Figure
6).
Figure
6.
Rear
view of
TV
with
a
75-Ohm
coaxial
cable
and a matching
transformer.
The antenna
installations
described
above
are the
most
common
types.
However, you
might
need
to
know
about a few
other
antenna
types
and
features.
If
your
TV
set
has a
75/300-Ohm
switch
on
the back,
be
sure
to set
the switch
in
the
300-Ohm
position.
If
your
TV
set
has a round jumper cable
protruding from the back,
be
sure the
jumper
cable
is
attached
to
the connector
next
to
it.
If
you have
cable
TV,
you might
want
to
contact
a
qualified
service
technician
for installation
assistance.