FM "T" Type Antenna - If the PreAmp/Tuner two is to be used in a strong FM signal area, a "T" type antenna (dipole)
may provide adequate reception. To connect this antenna, attach its leads to the 300 Ohm terminals, fully extend the
upper sections of the "T", and position them for greatest sensitivity (maximum indication of the "Tuned" indicators
when tuned to a broadcast station). In weak signal areas, a roof-top FM antenna will be required. A 3-element antenna
is generally sufficient for medium distances and an antenna with 5 or more elements may be required for long distances
and fringe areas. Two types of outdoor antenna cables are available: 300 Ohm balanced antennas and 75 Ohm
unbalanced antennas. 300 Ohm antennas use the same flat twin lead used by most TV antennas. 75 Ohm antennas use
a coaxial cable: these antennas are recommended for use in high interference areas such as adjacent to a road where
ignition noise may be present. When installing a roof-top antenna, check that it is pointing in the direction from which
most stations are received. Do not connect antenna leads to both the 75 and 300 Ohm inputs at the same time.
Use only the terminals corresponding to the antenna cable being used.
AM Loop Antenna - In an area where signals are strong, near to the broadcast stations, the AM Loop antenna provided
on the rear panel may be adequate. This antenna is effective in all areas except those where the signal strength is very
low, or in buildings made from reinforced concrete. Position this antenna so that as many "Tuned" indicators as
possible are lighted when tuned to an AM broadcast.
Outdoor Antenna - If you have difficulty in receiving clear AM broadcasts usng the Loop antenna, connect an
external antenna to the AM terminals. Set this antenna outdoors, as high as possible. Do not disconnect the provided
AM Loop antenna.
Outdoor Antenna Grounding - If an outside antenna is to be used with the PreAmp/Tuner Two, be sure that the
antenna system is grounded so as to provide some protection against voltage surges and built up static charges. Section
810 of the National Electrical Code, ANSI/NFPA No. 70-1984, provides information concerning supporting structure,
grounding of the lead in wires to an antenna discharge unit, size of grounding conductors, location of antenna discharge
unit, connections to grounding electrodes, and requirements for the grounding electrode. See figure 1.
Using the Antennas
2.
Antenna
Lead In
Wire
Antenna
Discharge Unit
(NEC Section 810-20)
Grounding Conductors
(NEC Section 810-21)
Ground
Clamps
Power Service
Grounding
Electrode System
(NEC Art 250, Part H)
Electric
Service
Equipment
Figure 1
