Daniels MT-3 User manual

MT-3 /MT-4 RADIO SYSTEMS
UHF AMPLIFIER
INSTRUCTION MANUAL
UT-3 / UT-4
406 - 470 MHz
Covers models: UT-3/400 Amplifier
UT-4/400 Amplifier
Copyright ©1998 Daniels Electronics Ltd. All rights reserved. No part of this publication may be
reproduced, stored in a retrieval system or transmitted in any form or by any means, electronic,
mechanical, photocopying, recording or otherwise, without the prior written consent of Daniels
Electronics Ltd.
DE™ is a registered trademark of Daniels Electronic Ltd. registered in the United States Patent and
Trademark Office.
Issue: Peliminary Previous Issue: N/A
Issue Date: October 98 Previous Issue Date: N/A Daniels Electronics Ltd.
Printing Date: October 98 Victoria, B.C.
Part No.: IM23D-UT 34400AMP PRINTED IN CANADA

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ii UHF Amplifier Instr uction Manual UT-3 406 - 512 MHz
Reviewed By:
Quality Assurance:
Larry Freeman _________________
Name Signature Date
NOTE:
The user's authority to operate this equipment could be revoked through any
changes or modifications not expressly approved by Daniels Electronics Ltd.
The design of this equipment is subject to change due to continuous
development. This equipment may incorporate minor changes in detail from the
information contained in this manual.

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UHF Amplifier Instruction Manual UT-3/UT-4 406 - 512 MHz iii
TABLE OF CONTENTS
Page
1 GENERAL.......................................................................................1-1
1.1 Introduction .............................................................................1-1
1.2 Perf ormance Specification ............................................................1-1
2 THEORY OF OPERATION ...................................................................2-1
2.1 Amplifier Operation ....................................................................2-1
2.2 Power Requirements ...................................................................2-2
2.3 RF Circuitry ............................................................................2-2
2.3.1 UT-3/400 Lowpass Filter ....................................................2-2
2.4 Power Control Circuitry ...............................................................2-3
2.5 Power Sensing Circuitry ..............................................................2-3
2.5.1 Output Power Sense..........................................................2-3
2.5.2 VSWRSense..................................................................2-4
2.5.3 VSWR Overload ..............................................................2-4
3 UT-3/400 AMPLIFIER ALIGNMENT ......................................................3-1
3.1 General..................................................................................3-1
3.2 RepairNote.............................................................................3-1
3.3 Recommended Test Equipment List.................................................3-1
3.4 Printed Circuitboard Numbering Convention .......................................3-2
3.5 Standard Factory Settings and Jumper Configuration............................. 3-2
3.6 UT-3/400 Amplifier Alignment .......................................................3-2
3.6.1 General.........................................................................3-2
3.6.2 UT-3/400 Amplifier Adjustment ............................................3-3
3.6.2.1 GeneralSet-Up.......................................................3-3
3.6.2.2 Output Power Alarm (Forward Power) ...........................3-4
3.6.2.3 Output Power.........................................................3-5
3.6.2.4 Antenna VSWR Alarm (ReversePower)..........................3-5
3.6.2.5 Antenna VSWR Overload ...........................................3-6
3.6.2.6 Procedure Verification ...............................................3-6
4 ILLUSTRATIONS AND SCHEMATIC DIAGRAMS ....................................4-1
4.1 UT-3/400 UHF Amplifier Component Layout.....................................4-2
4.2 UT-3/400 UHF Amplifier Schematic Diagram .....................................4-3
4.3 UT-3/400 UHF Lowpass Filter Component Layout...............................4-5
4.4 UT-3/400 UHF Lowpass Filter Schematic Diagram ...............................4-5

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iv UHF Amplifier Instr uction Manual UT-3 406 - 512 MHz
5 PARTSLISTS...................................................................................5-1
5.1 UT-4/400 UHF Amplifier Electrical PartsList......................................5-1
5.2 UT-4/400 UHF Amplifier Mechanical PartsList...................................5-4
5.3 UT-3/400 UHF Low Pass Filter Electrical PartsList..............................5-4
6 REVISION HISTORY ..........................................................................6-1

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UHF Amplifier Instruction Manual UT-3 406 - 512 MHz 1-1
1 GENERAL
1.1 Introduction
The UT-3/400 Amplifier provides the final stage of RF amplification and filtering for the entire
UHF Transmitter UT-3 406 -512 MHz family. The amplifier has four distinct frequency ranges:
406 to 430 MHz, 450 to 470 MHz, 470 to 490 MHz and 490 to 512 MHz as well as two distinct
output power ranges: 0.5 to 2.0 Wattsand 2.0 to 8.0 Watts. The UT-3/400 Amplifier is housed in
a machined aluminum case thatensures optimum RF shielding, provides a good ground, and also
acts as a heatsink.
Additionally, the UT-3/400 Amplifier is equipped with output power and VSWR sensing lines
which can be individually configured as open collector or linear outputs. The internal VSWR
sensor protects the amplifier from high antenna VSWR by approximately halving the amplifier's
RF gain when a VSWR overload condition is present.
Output filtering for the UT-3/400 Amplifier is provided by the UT-3/400 Lowpass Filter Board.
The lowpass filter assembly is mountedin a separate compartment of the amplifier case in order to
provided maximum attenuation of harmonic and other spurious signals.
Refer to Section 4 for the UT-3 406 - 512 MHz UHF amplifier and lowpass filter component
layouts and schematic diagrams
1.2 Performance Specification
Type: MT-3series UHF Amplifier module.
Compatibility: MT-3series Transmitter Main Board.
Frequency Range: 406 to 430 MHz, 450 to 470 MHz, 470 to 490 MHz or
490 to 512 MHz.
RF Power Output: adjustable 0.5 to 2.0 Wattsor 2.0 to 8.0 Watts
RF power Input: nominal level adjustable from +4 dBm to +10 dBm,
held within +/- 2 dB of nominal.
Ouput Impedance and VSWR: 50 Ω, Type N connector; 3:1 max. VSWR.
Input /Output Isolation: > 60 dB
Duty Cycle: 100%: Continuous operation from -40˚ C to +60˚C.

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1-2 UHF Amplifier Instruction Manual UT-3 406 - 512 MHz
HarmonicEmissions: Less than -80 dBc.
Transmitter Mismatch Protection: 20:1 VSWR at allphase angles.
Transmitter Alarm: Forward power sense and reverse VSWR;
- open collector output (separate or ' OR'ed configuration);
- linear output (separate lines only).
Operating Temperature Range: -30˚ C to +60˚ C, optional -40˚ C temperature test.
Operating Humidity: 95% RH (non-condensing) at +25˚ C.
Operating Voltage: +13.8 VdcNominal(range +11 to +16 Vdc),
+9.5 VdcRegulated.
Transmit Current: 0.7 Amp typical ; 1.1 Amp maximum
Amplifier Standby Current: less than 0.5 mA.
Amplifier Enable: Active to ground.
Amplifier Enable Response: typically overdamped, rising to within 90% of full power
within 5 msec; maximum (underdamped) overshoot of 30%.

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UHF Amplifier Instruction Manual UT-3 406 - 512 MHz 2-1
2 THEORY OF OPERATION
2.1 Amplifier Operation
The operation of the UT-3/400 Amplifier varies slightly according to whether the amplifier is a low
power (0.5-2.0 W) or a high power (2.0-8.0 W) version. The low power amplifier does not use
transistor Q1 to boost the output power; consequently, it does not require the +13.8 Vdc supply.
In both versions the power control circuitry monitors the RF output power of amplifier U4 and
keeps the power constant. Therefore, the output power from the high power amplifier will change
as the unregulated +13.8 Vdcsupply varies. Note thatthe frequencyband does not changehow the
amplifier operates; it only changes a few component values in the RF circuitry.
Power for the UT-3/400 Amplifier is provided from the MT-3 Transmitter Board. The +13.8 Vdc
supply (if required) is continuously connected to the amplifier; whereas, the +9.5 Vdc supply is
always switched by the transmitter's PTT circuitry. The UT-3/400 Amplifier will not consume any
power from the +13.8 Vdc supply until +9.5 Vdc is switched on for the amplifier's circuitry and
an RF input signal is present. The synthesizer or crystal control module controls the +9.5 Vdc to
the amplifier's circuitry; switching it on by grounding the amplifier's input enable line. The
synthesizer will ground the input enable line only when the synthesizer's RF signal is phase
locked. This prevents unwanted spurious emissions during transmitter start-up. A typical start-up
sequenceis listed below:
1) +13.8 Vdcis always present
2) the transmitter is keyed on
3) +9.5 Vdcis switched on by the PTT circuitry and the synthesizer
or crystalcontrolmodulePTT lineis pulledlow
4) an RF signal is output to the amplifier
5) the amplifier's input enable lineis activated
6) the amplifier outputs RF power

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2-2 UHF Amplifier Instruction Manual UT-3 406 - 512 MHz
2.2 Power Requirements
Typical current requirements for the UT-3/400 Amplifier at different power levels are given in the
Table 2-1 below. The current drawn from the +9.5 Vdc supply should never exceed 1.2 Amps
and the currentdrawn from the +13.8 Vdcsupply should never exceed 1.5 Amps.
Table 2-1 UT- 3/400 Amplifier Current Consumption
0.5 to 2.0 Watt Amplifier 2.0 to 8.0 Watt Amplifier
Output +9.5 Vdc Output +9.5 Vdc +13.8 Vdc
Power Supply Current Power
Supply Current
Supply Current
0.5 W 0.65 A 2.0 W 0.64 A 0.51 A
1.0 W 0.87 A 4.0 W 0.79 A 0.75 A
1.5 W 1.02 A 6.0 W 0.89 A 0.93 A
2.0 W 1.17 A 8.0 W 1.04 A 1.10 A
Note: Current consumption measured at 470 MHz
2.3 RF Circuitry
The RF circuitry consists of several blocks: a 5 dB input pad (R1, R2, and R3), an RF amplifier
module (U4), an output power boosting transistor (Q1), three directional couplers (TL1, TL3, and
TL4), and the UT-3/400 Lowpass Filter. The heart of the UT-3/400 Amplifier is RF amplifier
module U4. This module amplifies a 1 mW signal up to a maximum of 2.0 W, at the antenna
connector, for a low power unit. In high power units, the output of U4 is further amplified by Q1
to a maximum of 8.0 Watts at the antenna connector. Capacitors C17 and C24 provide tuning for
transistor Q1's input and output match. Although the input match and the output match for Q1 are
tunable, the networks have been made broadband so that the high power amplifiers will operate
over the same frequencyrange as the low power amplifiers. The frequency band of the UT-3/400
Amplifier is determined by the operating frequency range of the RF amplifier module U4.
Directional couplers (TL1, TL3, and TL4) are used to sample forward and reverse power. The
sampled power is used by the sensing and power control circuits to control the amplifier's
operation. The finalstep in the RF path is output filtering and, as mentioned earlier, this is done by
the UT-3/400 Lowpass Filter.
2.3.1 UT-3/400 Lowpass Filter
The UT-3/400 Lowpass Filter is a 50 ohm, 9 pole, reciprocal filter with a 3 dB cutoff frequency of
approximately 512 MHz. The lowpass filter assembly attenuates the desired signal's harmonics as
well as any other out-of-band emissions so that a 'clean' RF signal is output to the antenna
connector.

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UHF Amplifier Instruction Manual UT-3 406 - 512 MHz 2-3
2.4 Power Control Circuitry
The UT-3/400 Amplifier employs a closed loop power controlwhich uses a sample of the forward
RF power to controlthe gain of RF amplifier U4. Op-amp U1b compares the sampled RF voltage
to the output power setpoint and generates an error signal which Q3 uses to control the voltage on
U4's gain controlpin. The output power setpoint is determined by R7, the Output Power Adjust
potentiometer.
In low power amplifiers jumper JU5 is installed and the forward power is sampled by TL3, D6,
C27, R18, L11, R19, and C28. In high power amplifiers jumper JU5 is not installed and the
forward power is sampled by TL1, D5, C14, R13, L6, R12, and C15. In both high power and
low power amplifiers, the power control circuitry keeps the output power of U4 constant.
Therefore, in high power amplifiers, the amplifier's output power will fluctuate with variations in
the +13.8 Vdcsupply voltage.
2.5 Power Sensing Circuitry
The UT-3/400 Amplifier is equipped with output power and VSWR sensing lines which can be
individually configured as open collector or linear outputs. In open collector configuration, the
output is active low, thatis, when a fail condition is detected(not enough output power or too high
antenna VSWR) the open collector transistor is turned on. In linear configuration, a voltage
proportional to the sensed output power or antenna VSWR is output.
Both the Output Power Alarm setpoint and the VSWR Alarm setpoint are individually adjustable;
however, the Output Power Alarm setpoint must always be adjusted before the VSWR Alarm
setpoint. This is because the Output Power Alarm setpoint is used as a reference by the VSWR
Alarm circuitry.
2.5.1 Output Power Sense
The output power sense circuitry uses directional coupler TL3 to sample some of the forward
power. The sampled power is rectified by diode D6 and capacitor C27 and then amplified by
op-amp U3b. Op-amp U3b's amplification is controlled by R21, the output power alarm adjust
potentiometer. The amplified voltage is then output directly in linear operation (JU1 installed, JU2
not installed) or compared to +6.3 Vdc by op-amp U1a which then drives transistors Q5 and Q6
for open collector operatio n (JU1 not installed, JU2 installed).
In open collector configuration, Q6 (the open collector output transistor) is turned on when an
alarm condition occurs. The adjustment range for the output power alarm can vary depending on
the setting of R21 (the Output Power Alarm Adjust potentiometer).

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2-4 UHF Amplifier Instruction Manual UT-3 406 - 512 MHz
2.5.2 VSWR Sense
The VSWR sense circuitry uses directional coupler TL4 to sample some of the power reflected
from the antenna terminal. The reflected power is rectified by diode D7 and capacitor C33 and then
amplified by op-amp U2b. Op-amp U2b's amplification is controlled by R36, the VSWR Alarm
Adjust potentiometer. The amplified voltage is then output directly in linear operation (JU4
installed, JU3 not installed) or compared to the output power alarm setpoint by op-amp U3a which
then drives transistor Q7 for open collector operation (JU4 not installed, JU3 installed).
In open collector configuration, Q7 (the open collector output transistor) is turned on when an
alarm condition occurs. The adjustment range for the VSWR Alarm can depending on the setting
of R36 (the VSWR Alarm Adjust potentiometer).
2.5.3 VSWR Overload
The VSWR overload circuit protects the UT-3/400 Amplifier from excessive antenna VSWR by
reducing the amplifier's gain (output power) when an overload condition occurs. The VSWR
overload circuit (R38 to R41, R8, U2a, and Q4) is an extension of the VSWR sense circuit and
operates the same as the VSWR sense open collector circuit. The VSWR Overload Adjust
potentiometer (R38) reduces the voltage level of the VSWR Alarm Setpoint. The voltage set by
R38 is the compared to the output power alarm setpoint by op-amp U2a which then drives
transistor Q4. When transistor Q4 turns on, signaling an overload condition, resistor R8 is
grounded which reduces the output power setpoint. Reducingthe output power setpoint lowers the
UT-3/400 Amplifier's gain and protects the amplifiers from excessive current draw resulting from
high antenna VSWR.
The VSWR overload circuit's range of adjustment depends on the setting of the VSWR Alarm
Adjust potentiometer (R36). The VSWR overloadtransistor Q4 can be activated at the same point
at which the VSWR alarm becomes active or the VSWR overload circuit can be disabled by turning
R38 completely counterclockwise.

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UHF Amplifier Instruction Manual UT-3 406 - 512 MHz 3-1
3 UT-3/400 AMPLIFIER ALIGNMENT
3.1 General
Connectionsto the power supply, alarm and transmit enable lines (ENA), are clearly markedon 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 manualsfor eachmodule.
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 removedto expose all amplifier circuitry. All jumpers and test points are clearly marked.
3.2 Repair Note
The UT-3/400 Transmitter is mainly made up of surface mount devices which should not be
removedor replaced using an ordinary soldering iron. Removal and replacement of surface mount
componentsshould be performedonly with specifically designed surface mount rework and repair
stations complete with ElectroStatic Dissipative (ESD) protection.
When removingSurface Mount Solder Jumpers, it is recommended to use solder braid in place of
manual vacuumtype desolderingtools when removingjumpers. 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: Regulate d +9.5 Vdcat 0.1 A.
Regulated +13.8 Vdcat 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 three50 Ωcablesof incremental length20 to 40 cm
Alignment Tool: Johanson 4192

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3-2 UHF Amplifier Instruction Manual UT-3 406 - 512 MHz
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.
3.4 Printed Circuitboard Numbering Convention
To ease troubleshooting and maintenance procedures, Daniels Electronics Limited has adopted a
printed circuitboard (PCB) numbering convention in which the last two digits of the circuitboard
number representthe circuitboard version. For example:
• PCB number 43-9120 10 indicates circuitboard version 1.0;
• PCB number 50002- 02 indicates circuitboard version 2.0.
All PCB's manufactured by Daniels Electronics are identified by one of the above conventions.
3.5 Standard Factory Settings and Jumper Configuration
The UT-3/400 Amplifier is factoryconfiguredas follows:
• Open collector configuration for Output Power Alarm (3 dB drop).
• Open collector configuration for Antenna VSWR Alarm (VSWR ≥3:1).
• Output power of 2 Wattsor 6 Wattsfor low and high power amplifiers respectively.
The corresponding jumpersettings are:
• Jumper JU1: not installed Output power alarm - linear output
• Jumper JU2: installed Output power alarm - open collector output
• Jumper JU3: installed Antenna VSWR alarm - open collector output
• Jumper JU4: not installed Antenna VSWR alarm - linear output
• Jumper JU5: installed Low power (2 W) transmitters
• Jumper JU5: not installed High power (8 W) transmitters
3.6 UT-3/400 Amplifier Alignment
3.6.1 G eneral
The UT-3/400 Amplifier is a frequency sensitive modulethatis factoryassembledto operate in one
of four frequency bands: 406 to 430 MHz, 450 to 470 MHz, 470 to 490 MHz or 490 to 512
MHz. The amplifier is available in a low power version, 0.5 to 2.0 Watts output power, and a
high power version, 2.0 to 8.0 Watts output power. Both amplifier versions require 5 dBm of
input power and in both versions the amplifiers output power is continuously adjustable over the
its respective power range. The UT-3/400 Amplifier provides Output Power and Antenna VSWR
Alarm outputs which can be configured for open collector output or linear operation. The

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UHF Amplifier Instruction Manual UT-3 406 - 512 MHz 3-3
amplifier's output power level, alarm levels, and tuning for the transistor matching circuit in the
high power version can be set without detaching the amplifier from the transmitter board.
However, if the output power alarm or the Antenna VSWR alarm output configuration requires
changing, the UT-3/400 Amplifier must be detached from the MT-3 Transmitter Board. Refer to
section4 page 2 "UT-3/400 Amplifier Component Layout" for the location of solder jumpers JU1
to JU5.
3.6.2 UT-3/400 A mplifier Adjustment
The Amplifier alignment consists of two adjustment procedures; (i) a general set up (section
3.6.2.1) procedurewhich sets up the proper bias conditions for the RF transistors and (ii) the RF
threshold adjustments which set up the desired alarm threshold levels as well as the RF output
power. The general alignment procedureis required following major repair operations, changes in
RF input levelsor largechanges in operating frequency (greater than ± 1.0 MHz).
The RF output and alarm threshold level adjustments are more easily accessible so that fine
adjustments can be made in the field. Depending on user requirements, the RF alarm threshold
levels should be checked whenever a significant change in operating frequency (± 0.5 MHz) is
made. As the antenna VSWR alarm is dependent on the output power alarm, the output power
alarm should always be set first. The order of adjustment should be:
The adjustment procedures for the high power and the low power version amplifiers are identical
after the matching for transistor Q1 is tuned in the high power version. As the antenna VSWR
alarm is dependent on the output power alarm, the output power alarm should always be set first.
The order of adjustment should be:
1) High Power Amplifiers Only — Tune the transistor matching circuit at the
desired frequencyand power.
2) Set the desired output power alarm level (section 3.6.2.2).
3) Set the desired output power level (section 3.6.2.3).
4) Set the desired Antenna VSWR alarm level (section 3.6. 2.4).
5) Set the desired overload condition level (section 3.6.2.5).
Details for the preceding four steps are outlined below.
3.6.2.1 General Set-Up
1 Connect the transmitter's antenna output connector to the type N input of the radio
communications test set through a short sectionof low loss 50 Ω coaxial cable.
2 Turn all four (4) of the adjustment potentiometers (R7, R21, R36, and R38) fully
counterclockwise.

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3-4 UHF Amplifier Instruction Manual UT-3 406 - 512 MHz
3 Turn on the power to the transmitter.
4 For high power amplifier units, follow steps 5 to 7 below. For low power amplifiers,
skip to the Output Power Alarm procedure.
5 Tune the output matching capacitor for maximum output power. This should be
approximately 8 Watts.
6 For single frequencyapplications,tune the input matching capacitor so that +9.5 Vdc
currentis minimized without sacrificing output power. For wideband applications it
is best to tune the amplifier at the highest frequency in the band of interest and then
tune the input matching capacitor so that the +9.5 Vdc current never exceeds 1.2
amps over the desired frequencyband.
7 For single frequency applications, re-peak the output matching capacitor. For
wideband applications it is best to tune the amplifier at the highest frequency in the
band of interest and then re-peakthe output matching capacitor so that the +13.8 Vdc
currentnever exceeds1.5 amps over the desired frequencyband.
3.6.2.2 Output Power Alarm (Forward Power)
Open Collector Output
* note: the output power alarm output is factoryconfigured as an open collector output
so a pull-up resistor may be required on transmitter pin B26 if one is not already
present.
1 Adjust R7, the output power adjustment, to the output power at which the Output
Power Alarm is to be activated.
2 Monitor transmitter pin B26, the Output Power Alarm line, and slowly turn R21, the
output power alarm adjustment, clockwise until pin B26 goes low. The alarm is now
set for the currentoutput power of the transmitter.
Linear Output
1 Open the amplifier case to disable (open c ircuit) jumper JU2 and enable (short)
jumper JU1.
2 Monitor transmitter pin B26 with a voltmeter.
3 Adjust R7, the output power adjustment, for full transmitter output power.

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UHF Amplifier Instruction Manual UT-3 406 - 512 MHz 3-5
4 Adjust R21, the output power alarm adjustment, so that the voltmeter indicates +7.5
Vdcfor full transmitter output power.
5 Turn R7, the output power adjustment, fully counterclockwise. The voltmeter should
read approximately +3 Vdc.
6 Disconnect the voltmeter.
3.6.2.3 Output Power
1 Turn R7, the output power adjustment, clockwise to the desired transmitter output
power.
3.6.2.4 Antenna VSWR Alarm (Reverse Power)
Open Collector Output
* note: the antenna VSWR alarm output is factory configured as an open collector
output so a pull-up resistor may be required on transmitter pin Z26 if one is not
already present. The output power alarm must be set first before the antenna VSWR
alarm can be set.
1 Disconnect the radio communications test and terminate the transmitter with the 3:1
mismatch load.
2 Monitor pin Z26, the Antenna VSWR Alarm line, and turn R36 fully
counterclockwise. Pin Z26 should be high. Slowly turn R36 clockwise until pin
Z26 is pulledlow. Put the 50 ohm load back on again, Pin Z26 should go high. The
reverse power trip point is now set for a VSWR of 3:1.
Linear Output
1 Open the amplifier case to disable (open circuit) jumper JU3 and enable (short)
jumper JU4.
2 Monitor transmitter pin Z26 with a voltmeter.
3 Disconnect the radio communications test set and terminate the transmitter with the
3:1 mismatch load.

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3-6 UHF Amplifier Instruction Manual UT-3 406 - 512 MHz
4 Adjust R36, the VSWR alarm adjustment, so thatthe voltmeter indicates +5 Vdc for a
3:1 mismatch.
5 Put the 50 ohm load back on again. The voltmeter should read approximately 0 Vdc.
6 Disconnect the voltmeter.
3.6.2.5 Antenna VSWR Overload
1 Disconnect the radio communications test set and so that the amplifier is terminated
with an open circuit.
2 Monitor the currentfrom the +9.5 Vdcsupply.
3 Adjust R38, the VSWR overloadadjustment, clockwise until a noticeable drop in the
+9.5 Vdccurrentoccurs.
4 Reconnect the radio communications test set and, the +9.5 Vdc current should return
to the previous level.
3.6.2.6 Procedure Verification
1 Verify thatthe currentdrawn from the +13.8 Vdcsupply is less than 1.5 A and from
the +9.5 Vdcsupply is less than 1.2 A when transmitting full 8 W RF output power.
2 Turn off the power to the transmitter.

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4-1 UHF Amplifier Instruction Manual UT-3 406 - 512 MHz
4 ILLUSTRATIONS AND SCHEMATIC DIAGRAMS
This Page Intentionally Left Blank

VICTORIA B.C .
DATE.:
DWG No:
TITLE:
DDANIELS
ELECTRONICS
BOARD No.:
DWG REV DATE:
NOVEMBER 9, 1993 43-931613
Components installed on bottom of board
+
Components mounted on case
9316A6A
M3 x 8 Screws
M2.5 x 6 Screws
M3 x 8 - M2.5 Cap Sock
D2
Q1
L7 L10
R15
FB1 FB2
L5
C17
L8
C20
L9
C24
C19
WIRE
TL5
UT-3/400 LOWPASS FILTER ASSEMBLY
TL2
TL2
Q2
U4
TL3
TL4
IRF9540
1N5402
MRF641
100R
SEL
150n
0.6p-3.5p
150n
4u7
0.6p-3.5p
SEL
16 AWG, RED
UT-3/400 AMPLIFIER TH DESIGNATIONS AND VALUES
VICTORIA B.C .
DATE.:
DWG No:
TITLE:
DDANIELS
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BOARD No.:
DWG REV DATE:
Factory installed jumpers
UT-3/400 AMPLIFIER SM LAYOUT
NOVEMBER 9, 1993 43-931613
9316A4
Not required for low power units
C15
R25
C9
R1
R2 R3
R4
L1 L3
L2 L4
C4 C6
C7
C8
C1 C3
C2
C5
TL1
D3
D4
Q3
R5
D1
R6
R7
R8
U1
R9
C10
C11
R10
C12 C13
D5 R14
R13
L6
R11
C16 C18
C21 C22 C23
C25
C26
TL3
TL4
R32 R17
D6
C27
R18
L11
C28 R19
C29 C30
R20
R21
U3
U2
R24 R22 R23
R44
C31
C36
R34 C35
R42 R43
D7 L12
C33 R33
C34 R35
Q4
R39 R41 R40
R38 R36
R37
Q7
Q6
JU4
JU3
JU2JU1
R28
R29
R31
Q5 R30
R27
R26
C32
C14
JU5
R12
9316A5
1n
SEL
49k9
180n 180n
180n 180n
18n 18n
4u7
4u7
18n 18n
18n
18n
DIRECTIONAL
COUPLER
BYD17J
BYD17J
D5P06V
4k53
MBZ5233B
4k53
50k
27k4
33172
10k0
10n
100n
10k0
100n 10n
MMBD701 49R9
22k6
1u5
49k9
10k0
100n 10n 1n
DIRECTIONAL
COUPLER
DIRECTIONAL
COUPLER
49R9 49R9
MMBD701
150p
SEL
1u5
10n SEL
100n 10n
10k0
50k
33172
1k00 49k9 49k9
10k0
10n
10n
SEL 100n
1k00 27k4
MMBD701 1u5
150p SEL
10n 10k0
BC817
1k00 10k0
50k 50k
1k00
PZT2222A
PZT2222A
1k00
27k4
10k0
10k0
BC817 49k9
100k
49k9
10n
150p
33172
N/I
15p N/I
SEL
SEL
SEL SEL
UT-3/400 AMPLIFIER SM DESIGNATIONS AND VALUES
10n
MMBD701
4.1 UT-3/UT-4 UHF Amplifier Component Layout
4-2
DE DANIELS ELECTRONICS
UT3AMPM1A
UHF Amplifier Instruction Manual UT-3 406 - 512 MHz
Q2
IRF9540
D2
1N5402
TL5
MMBD701
WIRE
C37
10nF
C38
10u
+

OUTPUT POWER SELECT VALUES
COMPONENT
R18
0.5 - 2.0 Watts 2.0 - 8.0 Watts
R19
R33
R34
39k2
49k9
4k53
49k9
49k9
22k6
49k9
39k2
C25* 7.5 pF 4.7 pF
C26* 4.7 pF 3.0 pF
denotes components only installed on high power (2.0 - 8.0 Watt) units.
FREQUENCY BAND SELECT VALUES
COMPONENT 406 - 430 MHz 450 - 470 MHz
C19* 47 pF 39 pF
U4 MHW707-1 MHW707-2
NOTE: *
3.0 pF
3.0 pF3.0 pF
Not Installed
470 - 495 MHz 495 - 512 MHz
30 pF 30 pF
MHW707-3 MHW707-4
UT-3 / UT-4 SELECT VALUES
COMPONENT
R1
UT-3 406-470 UT-4 406-470
R2
R3
12k1
422R
422R
-
0R0
NOT INSTALLED
NOT INSTALLED
-
-
VICTORIA B.C.
DE DANIELS
ELECTRONICS
DE DANIELS
ELECTRONICS
DWG REV DATE: 19 OCTOBER 1998DWG No: UT3AMPM2B
TITLE: UT-3/UT-4 AMPLIFIER SCHEMATIC DIAGRAM
4.2 UT-3/UT-4 UHF Amplifier Schematic Diagram
4-3
UHF Amplifier Instruction Manual UT-3 406 - 512 MHz
C38 D7
APRVD:DATE: 23 JANUARY 1991 DWN BY: MICHAEL GAUBE
BOARD No: 43-931613 BOARD REV: VERSION 1.3
ANTENNA
VSWR
ALARM
OUTPUT POWER
ALARM ADJUST
VSWR
OVERLOAD
ADJUST
R16
U4TL5
R44Q7L12
JU5J2FIL5
FB2
OVERLOAD VSWR ALARM SETPOINT
UNUSED REFERENCE DESIGNATORS
HIGHEST REFERENCE DESIGNATION
RF IN
OUTPUT POWER
SETPOINT
OUTPUT
POWER
ADJUST
OUTPUT
POWER
ALARM
+13.8 VDC
AMPLIFIER
ENABLE INPUT
+9.5 VDC
RF OUT
VSWR
ALARM
ADJUST
OUTPUT POWER
ALARM SETPOINT
2 dB PAD
R9
10k0
C2
18nF
C10
10nF
R7
50k
R5
4k53
R10
10k0
C11
100nF
DS
Q3
D5P06V
R3
SEL
R1
SEL
R4
49k9
D2
IN5402
LPF
FIL1
LPF
FIL2
LPF
FIL3
C9
1nF
C1
18nF
C3
18nF
C5
18nF
C6
18nF
C4
18nF
+ C7
4.7uF
L1
180nH
DS
Q2
IRF9540
R6
4k53
D4
BYD17J
R2
SEL
D3
BYD17J
L3
180nH
L4
180nH
L5
150nH
R35
10k0
C34
10nF
Q7
PZT2222A
R44
10k0
R36
50k
C33
150pF
R33
SEL
R42
1k00
R43
27k4
R23
49k9
C31
10nF
C36
10nF
6
5
8
7
4
U2b
MC33172
D7
MMBD701
R22
49k9
R20
10k0
R19
SEL
C28
10nF
C27
150pF
R18
SEL
L11
1.5uH
D6
MMBD701
Q5
BC817-25 R29
10k0 R25
1k00
R28
27k4
Q4
BC817-25
R41
10k0
R39
1k00
R27
100k
C32
10nF
R26
49k9
R30
49k9
Q6
PZT2222A
R31
10k0
R38
50k
R37
1k00
JU1
JU4
R24
1k00
2
3
1
MC33172
U3a
2
3
1
MC33172
U2a
6
5
8
7
4
U3b
MC33172
C29
100nF
C30
10nF
LPF
FIL4 JU2
LPF
FIL5 JU3
C35
100nF
R21
50k
L6*
1.5uH
C14*
150pF
D5*
MMBD701
L2
180nH
R40
Not Installed
TL3
DIRECTIONAL COUPLER
TL4
DIRECTIONAL COUPLER
R17
49R9
R32
49R9
J2
TL5
CONFORMABLE
COAX
LPF
LOWPASS FILTER
MHW 707
MHW707-SEL
U4
JU5
C12
100nF
C13
10nF
2
3
4
1
8
U1a
MC33172
6
5
7
MC33172
U1b
L12
1.5uH
R11
10k0
R12*
49k9
R13*
22k6
C15*
10nF
R8
27k4
R34
SEL
TO ALL SWITCHED
+9.5V
+13.8 VDC
SWITCHED
+9.5V
SWITCHED+9.5V
SWITCHED
+9.5V
SWITCHED
+9.5V
SWITCHED
+9.5V
Q1*
MRF641
+13.8 VDC
+ C8
4.7uF
TL2
CONFORMABLE
COAX
L9*
5.0 TURN
C16*
15pF
FB1*
C19*
SEL
C26*
SEL
+
C20*
4.7uF
C22*
10nF
C21*
100nF
C23*
1nF
L7*
0.75 TURN
L10*
1 TURN
FB2*
R15*
100R
TL1*
DIRECTIONAL COUPLER
R14*
49R9
C25*
SEL
SEL
C18*
C24*
0.6-3.5pF
L8*
150nH
C17*
0.6-3.5pF
D1
MBZ5233B
C37
10nF
10uF
C38
SMB
J1

DE DANIELS ELECTRONICS
4-4 UHF Amplifier Instruction Manual UT-3 406 - 512 MHz
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