User Manual

VHF 30W Power Amplifi er Instruction Manual
IM71-AMP3150-30
Alignment & Installation
12
Note: The proper setting of this indicator cannot
be guaranteed if a non-1/2 wavelength cable
is used between the output of the PA and the
antenna.
- OVERLOAD - (VSWR Overload Alarm) is used
to indicate that the load impedance mismatch
is extremely high and could potentially damage
the RF transistor. Under this condition, the gate
voltage to the transistor is dropped thus reducing
the RF output power and preventing damage to
the MOSFET. The factory threshold level is set
when the load terminal is open.
- OVER TEMP - (Over Temperature alarm) a
thermostat control switch interrupts the DC
supply voltage to the PA when the RF transistor
body temperature exceeds 80ºC (175ºF).
Utilizing circuit hysteresis, the thermostat will
reset at 75ºC (167ºF).
The fan is activated automatically when the
RF transistor body temperature reaches
approximately +40ºC (104ºF). The fan’s
operating temperature range is -20ºC (68ºF)
to +60ºC (140ºF). It will not operate when the
ambient temperature is below -20ºC (68ºF).