Codan Radio Communications VT-30 User Manual

VHF AMP-2 30 W Power Amplifi er Instruction Manual
IM71-AMP2150-30

Installation and Site Operation

1)  Confi rm exciter and PA are aligned for 

the same frequency. (See Alignment 
Procedure).

2)  Remove the blank cover plates or TX-RX 

pair in the “B” System subrack slots.

3)  Install the VHF AMP-2 in slot 36 (visible via 

the marker hole on the upper left VHF AMP-
2 front panel).

Note: If the unit is set up with the extender 

card there will be a voltage drop of +1 
to +1.5 VDC when the power amplifi er 
is transmitting. This voltage drop must 
be compensated for valid power O/P 
readings. Adjust the power supply for 
+13.8 VDC at the power amplifi er.

4)  Connect the output of the exciter to the input 

of the VHF AMP-2 power amplifi er with the 
cable provided.

5)  Connect the antenna system and key the 

transmitter. The LED indicators are defi ned 
as follows:

(optional)

 

Indicates +13.8 VDC is applied to the 
transmitter when the ON-OFF switch is 
activated. An internal connector on the 
sensor PCB disables the power indicator 
LED in the event standby LED current drain 
must be eliminated.

Indicator: 

 

Indicates that a preset forward RF power 
level is present at the transmitter output. The 
threshold level is internally adjustable for 
various RF output levels over the 20 - 30 W 
range.

(Over Temperature)

 

A thermostat control switch interrupts the 
input supply voltage (nominally +13.8 VDC) 
to the PA when the heat sink temperature 
exceeds 175°F (80°C). The over temp 
thermostat will reset at 145°F (63°C), thus 
providing hysteresis. The OT indicator 
is only operational when exciter drive is 
present.

The fan is activated automatically when the VHF 
PA O/P transistor temperature sensor reaches 
+40°C. The fan’s operating temperature range is 
-20°C to +60°C. The fan sensor will not activate 
the fan when ambient temperature is below 
-20°C.