AMERITRON ALS-606 - Safety and Lighting Grounding; Coaxial Line Isolators

Version 0A 18
Safety and Lighting Grounding
The power supply cabinet grounds through a safety ground pin on the power plug. This
system depends on a properly wired power outlet.
Lightning protection grounds do very little good at the operating desk. Lightning
protection grounds belong at the antenna cable entrance to the building. Station ground
rods must always electrically connect through low impedance and resistance
conductors to the power line entrance ground. The national electrical code in the USA
prohibits isolated ground systems at dwelling entrances. Isolated ground rods or
systems connected to conductors entering a dwelling increase damage likelihood during
storms, and increase fire hazard and shock risk.
RF grounds generally belong at the antenna or at the feed line entrance. With the
special exception of a small floating counterpoise grounds, RF grounds at or very near
the dwelling should bond into the mains ground outside the dwelling. This is especially
true with earth contact grounds.
There is a ground lug on the amplifier rear panel. This ground lug provides a convenient
chassis connection for operating positions with ground bus on the desk. A station
ground bus helps ensure desk area equipment cabinets are close to the same electrical
potential for radio frequencies and lower. Equipment ground lugs are NOT for
independent wires or connections to external ground rods or ground systems from each
piece of equipment. They are for connection to a desktop ground bus system common
to all equipment, if you prefer to use such a system.
Independent ground wire connections are counterproductive. Never use RF isolators
between the amplifier and radio. Never use long independent wires to external grounds.
Never connect desk equipment to ground rods that do not bond into the mains entrance
ground rod.
Coaxial Line Isolators
The goal of every operating position is to maintain all equipment cabinets and housings
at the same RF potential. Never install coaxial line isolators between desktop radio
equipment. Isolators on or near the desk are contrary to this goal, and actually promote
or encourage RF potential differences between different desk equipment. If an RF
problem appears at the operating position, correction, repair, or replacement of
defective equipment is in order.
Proper line-isolator installation points are either just outside the operating room entrance
and/or close to the problem’s actual source. If the antenna system has excessive
common mode current on feedlines, the desktop has defective cables or connectors, or
if equipment has poor equipment cabinet design such as poor cover bonding to chassis,
locate and correct the actual problem.