Codan Radio Communications VT-3H040-S-HSO User Manual

VT-3H040 VHF Enhanced Transmitter Instruction Manual 

1 

 

 
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. 
 
 

 
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.