DANIELS TM ELECTRONICS LTD. MT-3 RADIO SYSTEMS VHF AM TRANSMITTER INSTRUCTION MANUAL VT-3AM 118 - 138 MHz Covers Family Model: VT-3A130-SYD410 Copyright © 2000 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.
Reviewed By: Quality Assurance: Claudia Borman 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.
TABLE OF CONTENTS Page 1 GENERAL..................................................................................... 1.1 Introduction.............................................................................. 1.2 Manual Organization.................................................................... 1.3 Performance Specifications ............................................................ 1.3.1 Transmitter Specifications........................................................... 1.3.
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1 1.1 GENERAL Introduction The VT-3A130 Transmitter is a synthesized multichannel AM transmitter designed to interface with the MT-3 Repeater Systems, while still maintaining MT-2 system compatibility. Both MT-3 systems are characterized by dependable low maintenance performance under the most severe environmental conditions. All performance measurements comply with Industry Canada (IC) Standard Specification RSS 119 and 140, as well as the Federal Communications Commission Part 87 for AM equipment.
The following sub-manuals are contained within this document cluster: AM Transmitter Manual: This manual provides an overview of the complete transmitter, manual organization and assembly in terms of the other modules. MT-3AM Transmitter Main Board: This manual pertains to the AM 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.
Duty Cycle: 100%; Continuous operation from -30°C to +60°C. (- 40°C Optional) Spurious and Harmonic Emissions: More than 90 dB below carrier Key-On/Key-off Spectral Mask Transients are at least 80 dBc below for frequencies ±400 kHz from carrier. Input VSWR: 2.8:1 Maximum. Load VSWR tolerance: Z load = 20:1: Modulation: 6K00A3 Amplitude Modulation Transmitted Noise More than 45 dBc below carrier Operating Temperature Range: -30˚C to +60˚C, optional - 40˚C temperature test.
1.3.2 Audio Specifications Audio Input: -25 to 0 dBm into a 600Ω balanced load Audio Response: Flat audio; +1/-3 dB: 300 Hz - 3 kHz Audio Distortion: Less than 3% -40˚C to +60˚C at 30% modulation Less than 5% -40˚C to +60˚C at 90% modulation 1.3.3 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: 1.4 kg (3.0 lb.) Corrosion Prevention: Anodized aluminum construction. Stainless steel hardware.
2 2.1 SYSTEM OVERVIEW Transmitter Operation Several modules are integrated by the VT-3A130 Transmitter Main Board to provide the complete transmitter. The Front Panel Board and AM Audio Processor are soldered directly to the Transmitter Main Board and are treated collectively in the Transmitter Main Board Manual while the Power Amplifier and and the Frequency Synthesizer plug into the Transmitter Main Board and can be changed with minimal effort.
2.2 Frequency Selection 2.2.1 BCD Switch Option. For operation in this mode, the external channel select must be set to channel 01. Transmitter channel selection is achieved by setting a decimal number on four BCD frequency select switches, FSW1 through FSW4. The switch settings are scanned by the synthesizer module when the transmitter is first powered up, and the desired frequency is generated.
2.3 Transmitter Assembly and Alignment 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).
2.4 Recommended Test Equipment List Alignment of the transmitter requires the following test equipment or its equivalent. Dual Power Supply: Oscilloscope / Multimeter: Current Meter: Radio communications test set: VSWR 3:1 mismatch load: Alignment Tool: Regulated +9.5 Vdc at 2 A Regulated +13.8 Vdc at 2 A - Topward TPS-4000 Fluke 97 Scopemeter Fluke 75 multimeter Marconi Instruments 2955R JFW 50T-035-3.
3 ILLUSTRATIONS 3.
3.2 MT-3 Transmitter Case - Exploded View B A B B A B 3 FINGER GASKET (2) A AMTXM2A A Instructions 1. Remove the four screws (A) in the Front panel. 2. Remove the four screws (B) on the side of the Transmitter Case.
4 REVISION HISTORY ISSUE DATE DESCRIPTION AND (REASON) 1 May 97 • Issue 1. 2 Mar 00 • The transmitter is now capable of working over the whole AM frequency band (118 –138 MHz) without being re-tuned.
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