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
 DEDANIELSELECTRONICSVT-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.
 DEDANIELSELECTRONICS1-2  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.
 DEDANIELSELECTRONICSVT-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.
 DEDANIELSELECTRONICS1-4  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.).
 DEDANIELSELECTRONICSVT-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).
 DEDANIELSELECTRONICS1-6  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 SO2 gas test with no functional impairment and no change in contact resistance). Handle Text Colour:  Orange.
 DEDANIELSELECTRONICSVT-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.
 DEDANIELSELECTRONICS2-2  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#=Txfrequency−29 MHz 5.0 kHz        or  Txfrequency= CHNL#    kHz[]+MHz5x29    For channel numbers 5000 to 9999  CHNL#=Txfrequency−29 MHz6.25 kHz      + 5000   or  Txfrequency= (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
 DEDANIELSELECTRONICSVT-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).
 DEDANIELSELECTRONICS2-4  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,
 DEDANIELSELECTRONICSVT-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.
 DEDANIELSELECTRONICS2-6  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.

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