Codan Radio Communications VT-3H040-S VT-3H035-S & VT-3H045-S User Manual IM20 VT3040 1
Codan Radio Communications VT-3H035-S & VT-3H045-S IM20 VT3040 1
Users Manual
DANIELS
ELECTRONICS LTD.
®
MT-3 RADIO SYSTEMS
VHF TRANSMITTER
INSTRUCTION MANUAL
VT-3
29 - 50 MHz
Covers model: VT-3H035-SWA3, VT-3H045-SWA3
Copyright © 1997 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.
Issue: 1 Previous Issue: N/A
Issue Date: May 97 Previous Issue Date: N/A Daniels Electronics Ltd.
Printing Date: Sept 97 Victoria, B.C.
Part No.: IM20-VT3040 PRINTED IN CANADA
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VT-3H040 VHF Enhanced Transmitter Instruction Manual 1-1
1 GENERAL
1.1 Introduction
The VT-3H040 transmitter is a low power, synthesized FM transmitter capable of operating in
20 kHz or 25 kHz channels and within one of two bands: 29 MHz to 38 MHz or 38 MHz to 50
MHz. The transmitter is rated for continuous duty at an RF output power of 3.0 Watt. The RF
output power level is preset at the factory. A modular design allows each of the transmitter's
modules; MT-3 Transmitter Main Board, MT-3 Audio Processor, VT-3H040 Amplifier and OS-
3H040 Synthesizer to be individually assembled and tested. This facilitates construction, tuning,
maintainance as well as troubleshooting procedures. The synthesizer module can be programmed
to have up to 16 channels exclusive to one frequency band.
The VT-3H040 Transmitter is designed to interface with Daniels Electronics' MT-3 Repeater
System while maintaining MT-2 System compatibility. Both radio systems are characterized by
dependable, low maintanence performance under the most severe environmental conditions.
1.2 Manual Organization
The organization of this manual reflects the modular makeup of the VT-3 product line. Each
module is fully described within its respective submanual, all of which are contained within this
document. In general, each submanual contains:
1. A functional description and specification summary,
2. a detailed technical description (Theory of Operation) and
3. assembly, setup and alignment procedures relevent to that particular module.
The module manuals are as follows.
Note: material presented in a given "sub-manual" may include information related to other
module versions not directly appllicable to the VT-3H040 Transmitter family (eg, the OS-3H
Synthesizer Instruction Manual covers models from 29 MHz to 512 MHz).
Transmitter Manual: This manual provides an overview of the complete transmitter, manual
organization and assembly in terms of the other modules.
MT-3 Transmitter Main Board: This manual pertains to the audio processor module, transmitter
Main Board and Front Panel Board. Most of the user selectable options are accessed within the
Transmitter Main Board module, including channel selection. Since all external connections
(including power and signal lines) are made to the Transmitter Main Board, most of the material
pertaining to transmitter operation and installation is found here.
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1-2 VT-3H040 VHF Enhanced Transmitter Instruction Manual
VT-3H040 VHF Amplifier: The amplifier module provides the final stages of RF power
amplification and harmonic filtering for the transmitter. This manual is intended primarily as a
reference since the amplifier module is adjusted at the factory.
OS-3H040 Synthesizer: This manual pertains to the synthesizer module. Channel selection is
described in the 'Transmitter Main Board' Manual.
VT-3H040 Channel Designation Table: This document relates operating frequency to the
transmitter channel number (see section 2.1).
1.3 VT-3H040 Transmitter Family Models
The VT-3H040 line of transmitters has a single RF power output rating of 3.0 Watt, with wide
band FM (20 kHz or 25 kHz channels) and employs synthesizer based frequency generation. The
two basic (i.e. no options added) band specific models of the transmitter are as follows:
VT-3H035-SWA3: 29 MHz to 38 MHz
VT-3H045-SWA3 38 MHz to 50 MHz
The frequency is determined by the model of synthesizer and by the lowpass filter that is installed
in the amplifier module (see the VT-3H040 VHF Amplifier manual for details). A group of
channels spanning 38 MHz can be accomodated by one of the models providing that the
frequency span does not exceed 1.0 MHz. Model VT-3H035-SWA3 can operate at frequencies
up to 38.5 MHz and is the preferred choice when spanning 38 MHz. Consult the factory for
futher information regarding operation around this frequency.
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VT-3H040 VHF Enhanced Transmitter Instruction Manual 1-3
1.4 Performance Specifications
1.4.1 General
The following is a general set of specifications for the generic VT-3H040 transmitter. Additional
specifications, specific to individual modules may be found in their respective submanuals.
Type: MT-3 Series Transmitter
Family: VT-3H040
Compatibility: MT-2 Series and MT-3 Series Radio Systems
Frequency Range: 29.0 MHz to 50.0 MHz
RF Power Output: 3.0 Watt Fixed (± 1.5 dB with temperature and
supply voltage).
System Impedance: 50 ; Type N connector.
Duty Cycle: 100%: Continuous operation from -30˚ C to +60˚C
(optional -40˚ C to +60˚C).
Harmonic Emissions: More than 90 dB below carrier.
Spurious Emissions: More than 80 dB below carrier.
Transmitter Mismatch Protection: 20:1 VSWR at all phase angles.
Transmitter Alarm: Forward power sense and reverse VSWR;
- open collector output (separate or 'OR'ed);
- linear output (separate lines only).
Modulation: 16K0F3E
Synthesizer Reference Frequency: 9.600000 MHz or 10.000000 MHz ; selectable.
Channel Spacing: 20 / 25 kHz
Frequency Stability: Standard: ±1 ppm, -30˚C to +60˚C,
optional -40˚C to +60˚C
Channel Selection: In 5 kHz or 6.25 kHz increments selected through
four internal BCD rotary switches. Preset capability
for 16 channel memory selectable through external
control.
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1-4 VT-3H040 VHF Enhanced Transmitter Instruction Manual
Standby Current and rise time: 95 % RF power, 95 % system deviation within;
(See also 'Transmitter Main • 10 ms: typ. 185 mA (Mode 4);
Board Instruction Manual) • 25 ms: typ. 160 mA (Mode 2);
• 50 ms: typ. 15 mA (Mode 1);
• Mode 3 not used in Synthesized Transmitters.
DOC Type Approval RSS119 TBA, RSS122 TBA
FCC Type Acceptance: H4J-VT-3H040-S
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 Vdc Nominal (range +11 to +16 Vdc),
+9.5 Vdc Regulated.
Total Transmit Current: 0.8 Amp typical; 1.2 Amp maximum
Front Panel Controls: NORM (repeat mode), OFF, and KEY TX (Tx on).
PTT Activation: Active to ground with or without time-out timer.
Microphone activated with or without time-out
timer.
Front Panel switch: KEY TX - without time-out
timer; NORM - with or without time-out-timer;
Isolated (optional relay) with or without time-out
timer.
PTT Time Out Timer: Selectable from 1 sec. to 8 hrs. (factory set 5 min.).
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VT-3H040 VHF Enhanced Transmitter Instruction Manual 1-5
1.4.2 Audio Specifications
Audio Input: Balanced 600 ohm or unbalanced (optional).
Input level sensitivity, -25 dBm to 0 dBm.
Audio Response: Pre-emphasis (6 dB per octave); +1.0 to -2.0 dB
from 300 Hz to 3 kHz;
Flat Audio Response: +1 to -1 dB from 100 Hz to 3 kHz.
Audio Deviation: Preset to ±3.0 kHz with a 1 kHz tone.
Subtone Audio Input 1: 0.5 Vpp at 200 Hz for ±500 Hz deviation
(internally adjustable).
Subtone Audio Input 1 Frequency range: 60 Hz to 300 Hz.
Subtone Audio Input 2: 0.5 Vpp at 100 Hz for ±500 Hz deviation
(internally adjustable).
Subtone Audio Input 2 Frequency range: DC to 150 Hz.
Direct Modulation Input: 0.5 Vrms at 1 kHz or ±3 kHz deviation.
Direct Modulation Frequency range: DC to 5 kHz.
Audio Distortion: Less than 2.5% THD; 1 kHz tone at 1.5 kHz or
3 kHz deviation (-40°C to +60°C).
Hum and Noise: Better than 55 dB
(test receiver band limited: 400 Hz to 30 kHz).
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1-6 VT-3H040 VHF Enhanced Transmitter Instruction Manual
1.4.3 Physical Specifications
Physical Dimensions: Width: Height: Depth:
7.1 cm (2.8 in) 12.8 cm (5.05 in) 19 cm (7.5 in)
Module Weight: 1.5 kg (3.3 lbs)
Corrosion Prevention: Anodized aluminum construction. Stainless steel
hardware. Selectively conformal coated glass epoxy
2 and 4 layer printed circuitboards. Gold plated
module connectors.
Module Design: Compact Eurostandard modular design. Plug-in
modules mate with Daniels standard M3 repeater
subrack. Subracks / modules comply with IEEE
1101, DIN 41494 and IEC 297-3 (mechanical size /
modular arrangement).
External Connections: RF Connection: type N connector located on the
transmitter module front panel. Motherboard
Connections (Audio, Power, and Control) are made
through a 48 pin, gold plated, type F connector on
the rear of the transmitter module. User connection
made through mated "mother board" assembly of
the repeater subrack. Type F standard connector
complies with DIN 41612 Level 2 (200 mating
cycles, 4 day 10 ppm SO
2
gas test with no
functional impairment and no change in contact
resistance).
Handle Text Colour: Orange.
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VT-3H040 VHF Enhanced Transmitter Instruction Manual 2-1
2 SYSTEM OVERVIEW
2.1 Transmitter Operation
Several modules are integrated by the VT-3H040 Transmitter Main board to provide the
complete transmitter. The Transmitter Main Board, Front Panel Board and Audio Processor are
generic in that they apply to both transmitter models. The Front Panel Board and Audio
Processor are soldered directly to the Transmitter Main Board and are treated collectively in the
Transmitter Main Board Manual. The operating frequency range is determined by the choice of
Amplifier and Frequency Synthesizer, both of which plug in to the Transmitter Main Board and
can be changed with minimal effort. Circuitry and jumpers on the Transmitter Main Board
control the operation of all modules and the operation of the transmitter, overall. Technical
details and a complete description of transmitter operation can be found in the Transmitter Main
Board Manual.
The VT-3H040 transmitter requires two power supplies; a regulated +9.5 Vdc supply and a
+13.8 Vdc supply, the latter of which is connected only to the Amplifier Module. The
(nominally) +13.8 Vdc supply's range is +11 Vdc to +16 Vdc. The current drawn from the +13.8
Vdc supply (while transmitting at the rated power) varies between 450 mA to 1000 mA with
temperature, operating frequency and power supply voltage. The current drawn by the 13.8 Vdc
line should not exceed 1100 mA. The +9.5 Vdc current drawn by the transmitter in its quiescent
state depends on what modules are enabled during the inactive (PTT off) state. This aspect of
transmitter operation is controlled by jumper settings on the Transmitter Main Board (refer to the
Transmitter Main Board Manual). The minimum +9.5 Vdc quiescent current is typically 15 mA
and occurs when the Synthesizer and Audio Processor are disabled while the transmitter is off
(Mode 1). If Synthesizer and Audio Processor operation is maintained continuously (Mode 4),
the +9.5 Vdc quiescent current is approximately 185 mA. Maintaining continuous operation of
some modules dramatically decreases the turn on time of the transmitter.
The front panel depicted in Section 3.1 bears a DPDT toggle switch (mounted on the Front Panel
Board; see the Transmitter Main Board Manual) which controls the operation of the VT-3H040
Transmitter. When in the 'OFF' position, the transmitter is turned off; however, the +13.8 Vdc
remains on the Transmitter Main Board terminals and on the Amplifier Module. When in the
'KEYED' position, +9.5 Vdc is supplied to the transmitter circuitry and the transmitter is
continously transmitting. When this switch is in the 'NORM' position, +9.5 Vdc is supplied to the
transmitter circuitry although the transmitter remains quiescent until keyed from one of several
Push-To-Talk (hereafter PTT) inputs. The red indicator LED is illuminated during transmit.
Microphone, RF output and optional reference input are mounted on the front panel; power and
other signal connections are provided by a type 'F' connector at the rear of Transmitter Main
Board. Details on their function can be found in the Transmitter Main Board Manual.
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2-2 VT-3H040 VHF Enhanced Transmitter Instruction Manual
2.2 Frequency Selection
The operating frequency is determined by the synthesizer channel number selected. The relation
between channel number and operating frequency is, in general, specific to the family and model
of transmitter. In the case of both the VT-3H035 and VT-3H045 transmitter models, each
channel corresponds to either a 5 kHz or 6.25 kHz increment in frequency, depending on whether
the channel number is below 5000 or above 4999 respectively; beginning at a base frequency of
29.0 MHz. This relationship is summarized by the following formulas:
For channel numbers 0000 to 4999
CHNL#=
Tx
frequency
−
29
MHz
5.0 kHz
or
Tx
frequency
= CHNL# kHz
[
]
+
MHz5x29
For channel numbers 5000 to 9999
CHNL#=
Tx
frequency
−
29
MHz
6.25 kHz
+ 5000
or
Tx
frequency
= (CHNL# - 5000) kHz
[
]
+
MHz6.25x29
Alternatively, a frequency and channel lookup table is available in the 'Channel Designation
Table' manual for the VT-3H040.
A channel can be selected from a set of 15 (maximum possible) factory programmed channels by
the four channel select lines available at the rear 'F' connector on the Transmitter Main Board. A
single user selectable channel is set by switches located on the Transmitter Main Board. See the
Transmitter Main Board Manual for details.
2.3 Transmitter Assembly and Adjustment
All modules are mounted on the Transmitter Main Board which then forms a single assembly.
An enclosure is formed by an extruded aluminum shell that slides over the Transmitter Main
Board as illustrated in section 3.2). This shell also serves as a heatsink to remove heat from the
Amplifier module and for this reason, it is important that the four screws that bond the shell to
the amplifier module (Screws B in Section (3-2)) be installed before prolonged operation of the
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VT-3H040 VHF Enhanced Transmitter Instruction Manual 2-3
transmitter. Moreover, the surface of the Amplifier module that contacts the shell should be clean
and free of foreign material. The enclosure is completed by the installation of front and rear
plates which are fastened to the Transmitter Main Board (see Transmitter Main Board Manual
for parts lists).
Transmitter alignment is performed on a module by module basis and detailed steps are provided
in the respective manuals. Alignment is simplified by using an SR-3 Sub rack, SM-3 System
Monitor, and RF extender cable to provide transmitter power and signal interconnection.
Alternatively, +9.5 Vdc and +13.8 Vdc, as well as any required test signals, may be applied
directly to the individual modules. Refer to the corresponding manuals for details.
2.3.1 Complete Transmitter Alignment
A complete Transmitter Alignment is performed at the factory and should not be required under
normal circumstances. A large change in operating frequency, as discussed in the next section,
may require a complete realignment operation. This operation requires that all the transmitter
modules be aligned on a per module basis in the following order.
Sequence Module Manual Reference
(1) Transmitter Main Board Section 2.2 of this manual,
Transmitter Main Board Manual.
(2) Synthesizer Synthesizer Manual
(3) Amplifier Amplifier Manual
(4) Audio Processor Transmitter Main Board Manual
2.3.2 Frequency Change
The transmitter is initially aligned at the factory for the frequency stamped on the 'Factory Set
Operating Frequency' label (see section 3.1). This label should list the frequency at which the last
complete transmitter alignment was performed. For a small frequency change, a simple channel
change (see section 2.2) may be all that is required. A larger frequency change may involve the
realignment of other modules. The frequency change in question is the accumulated frequency
change in relation to the frequency stamped on the label. For example, if the frequency is
changed by 0.5 MHz from that stamped on the label, then a second frequency change of 1 MHz
in the same direction would result in a total change of 1.5 MHz. The action taken would be on
the basis of the 1.5 MHz value. Failure to perform a realignment after a large frequency change
could result in unreliable transmitter operation or transmitter operation that does not conform to
the published specifications. The allowable frequency change is summarized below.
Note: It is advisable to confirm these frequency ranges with the individual module manuals,
notably the amplifier and synthesizer, as they are subject to change with updated versions.
The values in the module manuals take precedent over those tabulated (following page).
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2-4 VT-3H040 VHF Enhanced Transmitter Instruction Manual
FOR MODEL VT-3H035:
Size of Frequency Change Modules to be Aligned
less than ± 0.2 MHz Transmitter Main Board (Channel Change)
between ± 0.2 and ± 0.5 MHz Transmitter Main Board (Channel Change),
Audio Processor (see section 2.3.4)
between ± 0.5 and ± 1.0 MHz Transmitter Main Board (Channel Change),
Audio Processor (see section 2.3.4),
Synthesizer
check RF alarm thresholds (section 2.3.5) (?)
± 1.0 MHz or greater Complete alignment
FOR MODEL VT-3H045:
Size of Frequency Change Modules to be Aligned
less than ± 0.2 MHz Transmitter Main Board (Channel Change)
between ± 0.2 and ± 0.5 MHz Transmitter Main Board (Channel Change),
Audio Processor (see section 2.3.4)
between ± 0.5 and ± 1.0 MHz Transmitter Main Board (Channel Change),
Audio Processor (see section 2.3.4),
check RF alarm thresholds (section 2.3.5) (?)
± 1.0 MHz or greater Complete alignment
NOTE (?): May not be applicable to all installations.
2.3.3 Output Power Adjustment
The RF power output of the amplifier is set to its rated value of 3.0 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. If the Synthesizer module is replaced, it is strongly
recommended that the amplifer undergo a realignment as described in the Amplifier Module,
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VT-3H040 VHF Enhanced Transmitter Instruction Manual 2-5
unless it is confirmed that the original and replacement synthesizer have identical output power
(within ± 0.5 dBm).
2.3.4 Deviation Setting
The transmitter maximum deviation range is set by jumpers at the factory to ± 5.0 kHz for the
VT-3H040 transmitter. However, under some conditions such as a large change in transmitter
operating frequency, the deviation control may need adjustment. The transmitter deviation is
dependent on the operating frequency and this dependency is likely to be more severe at the band
edges. For frequency changes exceeding ± 0.5 MHz, especially at the band edges, the deviation
should at least be checked and corrected if necessary. See the Audio Processor section of the
Transmitter Main Board Manual for details on setting the transmitter deviation. Note that the
adjustment of the balance compression levels, which is also discussed in the Audio Processor
alignment section, is not required as this adjustment should not be affected by a change in
frequency or deviation settings.
2.3.5 Setting RF Alarm Thresholds
The VSWR and Forward Power Alarms are factory preset to give alarm conditions for a 3:1
VSWR and 50 % forward power respectively. The Amplifier Manual describes how to adjust
these settings, should different levels be required. If the alarm thresholds are crital to operation
of a particular installation and if the transmitter undergos a large change in frequency (see section
2.3.2 above), the threshold alarm levels, particularly the VSWR alarm, should be checked.
2.4 Recommended Test Equipment List
Alignment of the transmitter requires the following test equipment or its equivalent.
Dual Power Supply: Regulated +9.5 Vdc at 2 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 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.
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2-6 VT-3H040 VHF Enhanced Transmitter Instruction Manual
2.5 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 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 circuit boards.
2.6 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 represent the circuitboard version. For example:
• PCB number 43-912010 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.