Instruction Manual

DE
DANIELS
ELECTRONICS
3-2 VT-3A130 Amplifier Instruction Manual
3.4 Recommended Test Equipment List
Alignment of the transmitter requires the following test equipment or its equivalent.
Dual Power Supply: Regulated +9.5 Vdc at 0.1 A.
Regulated +13.8 Vdc at 2 A - Topward TPS-4000
Oscilloscope / Multimeter: Fluke 97 Scopemeter
Current Meter: Fluke 75 multimeter
Radio communications test set: Marconi Instruments 2955R
VSWR 3:1 mismatch load: JFW 50T-035-3.0:1
Alignment Tool: Johanson 8766
3.5 VT-3A130 Amplifier Alignment
3.5.1 General
The VT-3A130 Amplifier is a module that is factory assembled to operate in the frequency band:
118MHz to 138MHz. The amplifier requires -5 dBm to 5 dBm of input power and is continuously
adjustable over its power range of 1.0 to 4.0 Watts.
3.5.2 VT-3A130 Amplifier Adjustment
1. Apply power to the amplifier's +13.8 Vdc and +9.5Vdc pins. The +9.5 Vdc power
supply must be well regulated.
2. Connect the amplifier's antenna output connector to the type N input of the radio
communications test set through a short section of low loss 50 Ω coaxial cable.
3. Turn the two of the adjustment potentiometers POWER ADJUST pot R19 and
AUDIO ADJUST pot R35 fully counterclockwise.
4. Turn DISTORTION ADJUST pot R14 and POWER CONTROL ADJUST pot R24
to its center position
6. Apply a non-modulated 118 MHz RF signal of - 5 dBm / +5 dBm to the RF INPUT
connector.
7. Turn on the amplifier by applying a ground to the amplifier ENABLE INPUT pin.
8. Adjust POWER ADJUST pot R19 so that the output power is about 4Watt by turning
it clockwise. Do not let the current through the transistor U1 exceed 1.5 A on the
+13.8 Vdc line.