6
28 volts. The exciter PA voltage will change with drive level. Efficiency of the amplifier will be
approximately 60%.
H. Maximum VSWR should never exceed 2:1. Should the amplifier see a VSWR higher than this it
will trip the alarm board and shut down both the amplifier and the exciter.
I. Alarm conditions which will shut down the amplifier are: VSWR of greater than 2:1; excessive
power output(higher than the rating); high temperature. Should the amplifier sense any of the
above conditions it will shut down and automatically attempt to restart after 90 seconds and will
attempt 4 times to restart. The unit will then shut down for 15 minutes; and again go through the
4 restart attempts. After four of these cycles the unit will go into a permanent shutdown. The
power must be recycled to reset the alarm circuits. The operator should always look at the front
panel to determine which alarm shut the unit down. This will aid in locating conditions which are
causing the problem should one exist.
J. Telemetry is provided on the rear panel to monitor the voltage, current, power, and reflected
power of the amplifier. Terminals are also provided to enable putting the amplifier in standby via
a momentary contact closure. A momentary contact closure will also reactivate the amplifier. A
second input is provided which will place the amplifier and exciter in standby. Two "BNC"
connectors labeled "REMOTE" are provided on the rear of the amplifier and another on the rear
of the exciter. Connect the exciter remote BNC to the either of the amplifier remote BNC
connectors. By placing a ground on the center pin of the second BNC connector the RF drive will
be shut down to the amplifier. This can be accomplished by placing a ground on the exciter
remote connection only.
K. High VSWR conditions may be caused by icing of the antenna during winter storms. Leaking
transmission lines may have moisture or damage may occur to the antenna itself. Do not attempt
to reset the alarm levels to circumvent an external problem. This will cause damage to the
expensive RF output transistors and void the warranty. The user should also provide effective
lightening protection such as sorted quarter wave stubs on the transmission line. Power line
protection is also recommended as lightening hits many time come in on the power or telephone
lines. The telemetry lines should also be protected if connected to the telephone lines or lines
exiting the building. A good grounding system will help ensure many years of reliable operation
from your solid state equipment.
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