Function and use of radio-frequency transmission systems
Of all the wireless transmission technologies, radio-frequency transmission has been around for the longest time. Not surprisingly, then, it is also the most common, and with respect to audio transmission systems for accessible sound, it proves to be the most powerful system with the largest ranges of coverage.
The basic configuration of a radio-transmission system consists of a transmitter and at least one receiver. The transmitter, which is connected to an audio source – to a microphone system or any other audio system, for example – picks up the audio signals to transmit them wirelessly to the receivers.
The receivers can be equipped with teleloops, which provide for the inductive transmission of the signals to the hearing aid.
Amplifying receivers with audio output jacks are also available and can be connect to the earphones or headphones.
HUMANTECHNIK accompanies you with full service.
During the planning, design and installation of acoustic transmission systems often have special knowledge required. That is why we offer a comprehensive consulting planners and operators and service package for this sector. From the information through a qualified expert design assistance to installation and commissioning, we accompany you with our consultancy service for the effective use of professional audio transmission equipment.
Areas of application
Radio-frequency audio transmission systems have already become well established as wireless headphones or TV listening systems in the home environment.
The systems described here, however, go above and beyond this, most importantly because they have been designed for professional applications – for example:
- in sport arenas or at other spacious event venues,
- in churches and other assembly halls,
- in lecture or seminar rooms, as in schools and universities
- and for open-air applications in particular, there is hardly an alternative to radio-frequency transmission.
In addition to these stationary applications, portable, so-called tour-guide systems have also proven useful in many areas. Some of the areas they can be used in include
- museums, art galleries,
- tourist attractions and special events
- or transportation.
The availability and use of several channels makes it possible to provide different information at the same time, for simultaneous interpreting into different languages, for example, or for the treatment of different topics for several listening groups located close to one another.
Outstanding features of radio-frequency transmission technology
- Transmitter and receiver do not require a direct »line of sight«. Radio waves can pass easily through normal house and building walls. Listeners take the sound along, even when they leave the room in which the transmitter is installed.
- This means that even very large areas can be easily supplied with audio signals.
- It is relatively easy to install RF transmitters, which also makes it inexpensive. The costs for
installation and hardware do not increase in proportion to the size of the area that
- The transmitters can be installed inconspicuously (except in metal enclosures) and do not mar or spoil the overall architectural picture.
- Sunlight, artificial light and the reflection conditions inside rooms do not affect transmission.
- RF transmission systems are easy and convenient to use, they are very portable and, with multi-channel functionality, they are very flexible in their uses and applications.
With respect to coverage, RF transmission systems are far superior to the two other transmission technologies described in this brochure.
With coverage ranges of up to more than 300 metres, it is possible to easily supply even large arenas with audio signals. The transmission distances of tour-guide systems with approximately 30 metres makes it possible to supply information even in large groups or groups in different locations.
Factors influencing the operation of radio-frequency transmission technology
- Other RF systems or electromagnetic emissions could have a negative effect on transmission and signal quality.
- Users must make sure that their transmission channels are set correctly.
- Some countries charge radio-licensing fees for the use of these systems. In this context, it cannot be ruled out that the national regulations in some countries only release certain frequency ranges for these systems (different from the standard).
More useful information on the use of radio-frequency transmission systems
- Users of audio radio-frequency transmission systems should be aware of the fact that the coverage ranges or the signal scattering go beyond the intended coverage areas. As a result, there is no guarantee that the information transmitted will remain confidential.
- When planning the parallel use of this type of system – in neighbouring rooms, for example – the transmission must be made on different channels (compare the number of channels available with the number of channels required).