User Manual
Table Of Contents
- 1GENERAL
- 1.1Introduction
- 1.2Performance Specification
- 2THEORY OF OPERATION
- 2.1Amplifier Operation
- 2.2Power Requirements
- 2.3RF Circuitry
- 2.3.1VT-3/150 Lowpass Filter
- 2.4Power Control Circuitry
- 2.5Power Sensing Circuitry
- 2.5.1Output Power Sense
- 2.5.2VSWR Sense
- 2.5.3VSWR Overload
- 3VT-3/150 AMPLIFIER ALIGNMENT
- 3.1General
- 3.2Repair Note
- 3.3Recommended Test Equipment List
- 3.4Printed Circuitboard Numbering Convention
- 3.5Standard Factory Settings and Jumper Configuration
- 3.6VT-3/150 AmplifierAlignment
- 3.6.1General
- 3.6.2VT-3/150 Amplifier Adjustment
- 3.6.2.1General Set-Up
- 3.6.2.2Output Power Alarm (Forward Power)
- 3.6.2.3Output Power
- 3.6.2.4Antenna VSWR Alarm (Reverse Power)
- 3.6.2.5Antenna VSWR Overload
- 3.6.2.6Procedure Verification
- 4ILLUSTRATIONS AND SCHEMATIC DIAGRAMS
- 4.1VT-3/150 VHF Amplifier Component Layout
- 4.2VT-3/150 VHF Amplifier Schematic Diagram
- 4.3VT-3/150 VHF Lowpass Filter Component Layout
- 4.4VT-3/150 VHF Lowpass Filter Schematic Diagram
- 5PARTS LISTS
- 5.1VT-3/150 Amplifier Electrical Parts List
- 5.2VT-3/150 Low Pass Filter Electrical Parts List
- 5.3VT-3/150 Amplifier Mechanical Parts List
- 6REVISION HISTORY
DE
DANIELS
ELECTRONICS
VHF Amplifier Instruction Manual VT-3 132 - 174 MHz
3-1
1
3
VT-3/150 AMPLIFIER ALIGNMENT
3.1
General
Connections to the power supply, alarm and
transmit
enable
lines (ENA), are
clearly
marked on the
amplifier
case. The
amplifier
is
enabled
when the
enable
line (ENA) is grounded.
If the
amplifier
is
installed
in the transmitter,
alignment
is
simplified
by using an SR-3 Subrack,
SM-3 System Monitor, and RF
extender
cable
to provide
transmitter
power and signal
interconnection
(see the
Transmitter
Main
Board
Manual
for details). For
complete
transmitter
alignment, the
Transmitter
Main
Board, Synthesizer,
Amplifier,
and Audio Processor should be
tuned in the
aforementioned
order. Please refer the corresponding manuals for each module.
If the input RF
level
is not changed,
adjustments
to the output power and
alarm
thresholds may be
made without removing the
amplifier
cover.
However,
in the case of a
complete
amplifier
alignment, the
amplifier
should be
separated
from the
Transmitter
Main
Board and the
amplifier
cover removed to expose all
amplifier
circuitry.
All
jumpers and test points are
clearly
marked.
3.2 Repair Note
The
VT-3/150
Amplifier
is
mainly
made up of surface mount devices which should not be removed
or
replaced
using an ordinary soldering iron.
Removal
and
replacement
of surface mount
components should be performed only with
specifically
designed surface mount rework and repair
stations
complete
with
ElectroStatic
Dissipative
(ESD) protection.
When removing Surface
Mount
Solder
Jumpers,
it is
recommended
to use solder braid in
place
of
manual
vacuum type desoldering tools when removing jumpers. This will help prevent
damage
to
the circuitboards.
3.3 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
coaxial
test
cable
set three 50 Ω cables of
incremental
length 20 to 40 cm
Alignment
Tool:
Johanson 4192