Surveillance Guide

Audio Surveillance

What is audio surveillance?

Audio surveillance provides the ability to monitor a room of telephone conversation which can either be recorded in situ or transmitted to a receiver/recorder away from the environment.

We produce a range of equipment to suit almost every situation.

A guide to audio surveillance 

Under what circumstances is audio surveillance used?
One: When the requirement is to record the conversation to which you are party, e.g. to provide evidence of a verbal contract.
Two: When it is necessary to listen to and/or record a conversation in surroundings that you cannot be present, e.g. to prove conspiracy.

What is a radio transmitter and how does it work?

Transmitters are generally easily hidden devices that listen to room or telephone conversations. Sometimes they are disguised as pens, calculators electrical or telephone sockets etc.
The conversation is invisibly transmitted over the air waves to a radio receiver.

Room monitoring

There are several different options outlined below.

Portable systems
Portable recording or transmitting systems are ideal for meetings or negotiations which take place in a situation without you direct control. A recording briefcase, pen transmitter or calculator transmitter etc provide a superb means of achieving excellent results. This type of device can accompany you into a room and be operated at your discretion to transmit or record a conversation.

Static systems
If there is a requirement to listen to and/or record a conversation at which you are not present, the most effective method is to install a radio transmitting device. The alternatives are:
One: A battery operated transmitter for regular access or short-term use is relatively inexpensive and can be easily concealed. Practical lengths of transmission time vary according to the type of device and battery chosen.
Two: For long-term use where regular access is inconvenient or impossible, a mains electricity connected device is recommended. This type of equipment is easy to install and can be left to operate indefinitely.

FM Audio Transmitters

These "bugs" transmit in air band frequency ranges. This is above normal radio station frequencies. You require an air band compatible receiver to listen to conversation which you tune in the same manner as a conventional radio. It can be used for room or telephone conversations. Distance and clarity are adequate but for more professional monitoring we suggest our crystal controlled equipment.

UHF Audio Transmitters

For professional equipment to ensure clarity and distance we suggest that Ultra High Frequency transmitters are used. These transmitters are crystal tuned and locked to provide total stability. 
We have two ranges of UHF Transmitters: Our silver range is for semi professional use and are of a high quality while our Gold range is aimed for important professional applications.

Telephone surveillance

There are two main methods to monitor a phone conversation.

Wire Tap
These devices connect between the telephone line to be monitored and a tape recorder. When the phone line is in use the recorder will activate and record both sides of the conversation. When the telephone line is not in use, the recorder's switch off to conserve tape and battery life.

Telephone Transmitter
A telephone transmitter is a small device which is connected to the telephone line or hidden inside a telephone socket, double adaptor or in the actual telephone itself. This device will transmit both sides of the conversation whenever the telephone is used. This can be monitored by a receiver located some distance away to record the conversation.