DTC Communications VXS250 User Manual

1/4 Watt Video Transmitter

1/4 Watt Video Transmitter

Operator Guide

Operator Guide

VBS-250 Frequency 2400-2500MHz

VBL-250 Frequency 1700-1850MHz

DTC COMMUNICATIONS INCORPORATED

How to contact DTC

For operator and troubleshooting
information, customers are encouraged to refer to
the details in this manual. For additional clarification
or instruction, or to order parts, contact DTC.
Customer Service is available Monday through
Friday between the hours of 9:00 AM and 5:00 PM
EST at:
T el: 603-880-441 1
Fax: [phone]
Website: www.dtccom.com
Email: [e-mail]

486 Amherst Street
Nashua, New Hampshire 03063
USA

Copyright Notice

Copyright © 2002
DTC Communications, Inc. All rights
reserved. No part of this document may be
reproduced, transmitted, transcribed, stored in a re­trieval system or translated into any
language or computer language, in any form or by
any means, including but not limited to electronic,
magnetic, mechanical, optical, chemical, manual or
otherwise, without the prior written permission of DTC
Communications, Inc.

Disclaimer

The information in the document is subject to change
without notice. DTC makes no representations or war­ranties with respect to the contents hereof, and spe­cifically disclaims any implied warranties of merchant­ability or fitness for a particular purpose. DTC reserves
the right to revise this publication and to make changes
from time to time in the content hereof without obliga­tion of DTC to notify any person of such revision or
changes.

Trademarks

Trademarks of DTC Communications, Inc. include:

• DTC

®

• MiniPIX

• DynaPIX
Other product names used in this manual are the prop­erties of their respective owners.

®

Warranty

DTC warrants its manufactured components against
defects in material and workmanship for a period of
two (2) years, commencing on the date of original pur­chase.
Products manufactured by others that are approved
for use with DTC equipment are warranted for the
manufacturer’s warranty period, commencing from the
date of shipment from DTC.

FCC information

The following information is provided as a
service to our law enforcement customers who
require a Part 90 station license for video
surveillance operations using the 2450 to 2483.5 MHz
band.

Y ou will need to provide:

• Form 600 (the application form)

Forms can be obtained from the FCC on their web­site at:

www.fcc.gov

You can also contact the FCC using their FAX back
service at: [phone]

Additional instructions are available by telephone at:
[phone]

The filing fee form is returned to:

Federal Communications Commission
1270 Fairfield Road
Gettysburg, PA 17325-7245

2

DTC COMMUNICATIONS, INC.

PN OP1920256 REV2

Manual Conventions

NOTE Describes special issues
you should be aware of while
using a particular function.

WARNING Calls out situations in
which equipment could be
damaged or a process could be
incorrectly implemented, but in
which operator safety is not a
factor.

TIP Describes application hints.

RF EXPOSURE ST ATEMENT

In bodyworn deployments, when installed as directed, this equipment complies
with the FCC radiation exposure limits set forth for an Occupational/Controlled
environment. Only antennas specifically designed and tested by DTC for on-body
applications should be used.
In General Population/Uncontrolled environments, proper spacing must be
maintained between the radiating surface of the antenna and any person’s body. In
the case of a simple dipole antenna with (2.1 dBi gain), a minimum spacing of 2.5"
must be maintained. In the case of gain antennas up to (17dBi), a minimum
spacing of 12.5" must be maintained.

Table of Contents

DTC COMMUNICATIONS, INC.

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QUICK START GUIDE

VBS/VBL-250 Video Transmitter

4

6

5

7 1

3

1 Make sure that the ON/OFF switch is set to OFF. (Red dot is OFF).
2 Install 4 “AA” batteries in the internal battery compartment of the module.

(Lithium batteries are recommended)

Note: The module is power efficient, enabling 3 hours of operation.

3 Using a screwdriver, turn the channel selector to the correct transmission

channel number.

4 Connect an antenna to the ANTENNA connector on the module.
5 Connect the microphone or microphones to the MIC-1 and MIC-2 connectors

on the module.

6 Connect a video source to the Video/Multi I/O connector.
7 Slide the power switch to the ON position (Green dot is ON) to apply power to

the transmitter.

Note: While installing the batteries, observe proper polarity as printed
in the battery compartment. Reverse polarity protection is a built-in
design feature of the transmitter. If a battery is installed backwards, this
feature prevents the transmitter from powering up, without damaging
the transmitter or battery.

2

Warning: Do not apply power to
the transmitter until an antenna
has been connected in step 4.

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DTC COMMUNICATIONS, INC.

VBS/VBL-250 Video Transmitter

OVERVIEW

What should you expect to receive with your 250mW Transmitter?
1 VBS/VBL Video Transmitter

1 Dipole antenna with right angle SMA connector
1 One Video and Power In “Y” cable
1 DTC programming software and cable

The VBS and VBL transmitters are small module transmitters designed for both on and off body applications. They are part of
a family of video transmitters from DTC that provide 250mW, 2 Watts and 5 Watts output power.

Feature

Programmable

Efficient Switching Power
Supply

Description

User programmable video channels, selectable in 250kHz steps. Two user
programmable audio sub carriers, selectable in 10kHz steps from 6 MHz to

7.5MHz.

• Audio sub carriers are OFF unless microphones are attached. The
transmitter automatically senses when a microphone has been attached.

• The audio sub carriers are phase locked, and will not drift into the video
signal.

• Automatic Gain Control is provided on each audio input, amplifying soft
sounds.

• They generate far less heat than a traditional video transmitters.

• They operate significantly longer than traditional video transmitters on the
same power source.

NOTE: The dipole antenna included is not recommended for normal
use! This antenna enables you to quickly set up your transmitter and
ensure proper operation. DTC highly recommends the use of
circularly polarized antennas for the best rejection of multi-path.

NOTE: DTC has provided you with a “Y” cable (power and video)
terminated with a BNC connector for your convenience.

DTC COMMUNICATIONS, INC.

5

FEATURES

Feature

Remote Switching Capability

External Power Loop Through

Encryption Option

Description

• You may turn the device ON or OFF, remotely, by attaching a switch to one

of the pins on the Multi I/O connector. DTC provides hard-wired and wireless
switches for this application.

• The power applied to the Multi I/O pin is automatically looped through the
unit, and available on a second pin to power a remote device, such as a
camera. If you apply 9 Volts in, you will get 9 Volts out.

WARNING:Make sure your camera will operate on the voltage being
supplied to the transmitter.

• The VBL/S series supports Ovation Micro ViewLock II encryption, which
adds approximately .35” to the width of the unit.

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DTC COMMUNICATIONS, INC.

Specifications for the Module (VBS/VBL-250)

Power Supply Internal batteries 4 “AA”lithium batteries or external 9-16Vdc.
Power Consumption 2.5 Watts (not including camera)
Battery life 3 hours
Reverse polarity

protection yes
Dimensions 2.5x4.5x0.675”
Camera Power Using external power input: Same as supply voltage,

switched (200mA max)
Using internal batteries: 5Vdc@175mA,switched (internal
regulator)

Controls 10 channel select rotary switch

Panel mounted, slide ON/OFF switch
VMx -2000 2 Watt Unit only

Connectors 2 pin Lemo: Mic 1

2 pin Lemo: Mic 2
SMA: Antenna
6 pin Multi I/O: Video in, Data in, DC input 9-16Vdc,

camera power, Remote ON/OFF, Multiplexed Data out,
Ground

Programmability Video: 2400-2500MHz (VBS-250)

1700-1850MHz (VBL-250)
250KHz resolution steps
Audio: User programmable from 6.0-7.5 MHz, in
10kHz steps

Chassis notes Machined solid aluminum with rounded edges.

Audio

General Mic level input (line level factory opt.) 50-3000Hz

Phased locked with AGC on both inputs. Sub-carrier auto
sensing, only active when microphone is attached.

Number of sub-carriers 2
Sub-carriers frequencies 6.0-7.5MHz , user programmable

SPECIFICATIONS

DTC COMMUNICATIONS, INC.

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SPECIFICATIONS

Sub-carrier ON/OFF
control Subcarriers are activated when mic is connected.

Subcarrier frequency
stability +/- 0.003%, -30 to +70°C

Sub-Carrier Deviation 50kHz peak
Audio S/N 45dB min.
Frequency Response BW

= 50-3000Hz

1.5dB

Total Harmonic Distortion <2%
Input Level 8 mVpp@400Hz for 50 kHz peak dev.
Pre-Emphasis 75uS
Input Impedance 10k Ohm

Video

Video Frequency
Response BW

= 6 Hz - 5.0 MHz

1.5dB

Input Input Impedance 75 Ohms
Input Level 1V

p-p

Max.

S/N 60 dB min.
Pre-Emphasis Per CCIR 405 525 line curve
Differential Gain 5%

RF

Operating Frequency 1700-1850MHz, 250KHz resolution steps

2400-2500MHz, 250KHz resolution steps

Power output 250 mW min. @ nominal supply voltage, 25 Deg. C.

-3dB @ 3.6Vdc int

-2 dB over temp.

Output Impedance 50 Ohms
Spurs and Harmonics

output -50 dBc

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DTC COMMUNICATIONS, INC.

Load Pull Stability 8:1 VSWR