AMERITRON AL-572, Инструкция по эксплуатации

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Ameritron AL-572 Instruction Manual
15
For 120 volt operation, the wiring between the fuse box and the amplifier ac outlet must be
number 14 gauge (or larger) in order to supply the current required (16 A) without a significant
drop in the line voltage. The 120 volt outlet should be fused for 20 amperes.
G
ROUNDING
Connect a good RF and dc ground to the ground post on the rear panel of the amplifier. Use the
heaviest and shortest connection possible. The best materials to use for ground connections are
(in order of effectiveness) smooth wide copper flashing, copper tubing, or solid copper wire.
Never use braided or woven conductors unless the lead needs to be flexed. Braided or woven
conductors offer a much higher impedance to lightning and RF than an equivalent solid
conductors.
Water pipes, metal heating ducts, metal fences and other large metallic masses offer convenient
RF grounds. If a water pipe ground is used, inspect all the pipe connections to be sure that no
plastic or rubber connections are insulating the pipes. Insulated pipe connections will interrupt
the electrical continuity in the water supply system. Install a jumper around any insulated pipe
connections you find. Use heavy copper wire or flashing with stainless hose or pipe clamps for
the jumpers.
The following tips will help prevent lightning damage and RF grounding problems:
1. Avoid using braided or woven conductors, they have very high resistance for RF and
lightning. Remember that RF and lightning flows along the surface of conductors, almost no
current flows in the center of the conductor. The lowest RF resistance occurs with large
surface area, smooth conductors.
2. Avoid routing a single small gauge conductor along the various pieces of equipment (or to
connect multiple ground sources). Instead, use multiple ground leads that connect to a single
wide buss at the operating position. Keep all ground leads as short and wide as possible.
3. Buried radials provide much better lightning and RF ground connections than ground rods do,
although both are needed for safety.
4. Avoid sharp bends in ground leads. When changing the direction of a ground lead use a
gradual radius turn.
5. Avoid second story operation. A good ground is much easier to obtain on the first floor or in
the basement of a structure.
6. Air-core choke baluns should be used on all coaxial feedlines. The feedlines should be coiled
into several 4" to 6" diameter turns before they enter the building. Either directly bury the
feedlines a few inches deep in the ground for a minimum distance of ten feet or ground the
shields to a separate earth ground on the antenna side of the choke.