Codan Radio Communications AMP-3-150 User Manual

Page of 12
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).