User Manual

Table Of Contents
DE
DANIELS
ELECTRONICS
3-4 UT-4R400 UHF Project 25
Digital
Transmitter
Instruction
Manual
signal
generated
by the transmitter. Key the
transmitter
by moving the front panel power switch to
the
“KEY”
position and adjust pot R11 to
achieve
a
deviation
of 3 kHz (for a 25 kHz wide
channel)
or 1.5 kHz (for a 12.5 kHz wide channel).
Next, de-key the
transmitter
and remove the audio signal generator. Connect the signal
generator
to
microphone
connector
MIC1-2. Key the
transmitter
by moving the front panel power switch to
the
“KEY”
position.
Adjust
pot R9 to
achieve
a
deviation
of 3 kHz kHz (for a 25 kHz wide
channel)
or 1.5 kHz (for a 12.5 kHz wide channel). This
completes
the audio
level
alignment
procedure.
3.4.7
Amplifier
Alignment
The RF power output of the
amplifier
is set to its rated value of 2.0 Watts or 8.0 Watts at the
factory. This should not require
adjustment
under normal circumstances.
However,
should it be
necessary to
correct
the output
power,
the 'Output Power Adjustment’, which is described in the
Amplifier
Manual, can be adjusted accordingly. Power
adjustment
may also be required when the
transmitter's
operating
frequency is changed. When a large frequency change has been
programmed
into the transmitter, the
amplifier
should be
aligned
at the new frequency
according
to
the
Amplifier
Manual.
3.5 Recommended
Test
Equipment List
Alignment
of the
transmitter
requires the following test
equipment
or its equivalent.
Dual
Power Supply:
Regulated
+9.5
Vdc at 2 A.
Regulated
+13.8
Vdc at 2 A - Topward TPS-4000
Oscillo
scope /
Multimeter:
Fluke 97
Scopemeter
Current
Meter:
Fluke 75
multimeter
Radio
communications
test set:
Marconi
Instruments 2955R (analog only)
Motorola
R2670 with Project 25 option
Alignment
Tool:
Johanson 4192
It is
recommended
that the radio
communications
test set be frequency locked to an
external
reference
(WWVH,
GPS,
Loran C) so that the high
stability
oscillator
may be
accurately
set to
within its ±1 ppm frequency tolerance.
3.6 Repair
Note
The
transmitter
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
Elect
roStatic
Discharge
(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
circuit
boards.