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radio frequency (RF) vs. infrared (IR) transmission
what is RF and IR?
To begin with, just what do these terms mean?
Webster's Unabridged Dictionary tells us that radio frequency (RF) is a frequency in the electromagnetic spectrum within which radio waves may be transmitted, from about 3 kilohertz to about 300,000 megahertz.
Conversely, Webster goes on to state that infrared (IR) is electromagnetic radiation with wavelengths longer than visible light but shorter than radio waves.
Thanks for clearing that up Mr. Webster!
The electro-magnetic spectrum is wide and varied, even bewildering in its choices and applications. Moreover, with all the different types of hearing assistance products available, it's easy to get confused about which type is right for your particular needs. Many factors come into play, such as coverage area, cost of equipment, even ease of use. However, the most basic considerations come down to these two: environment and application.
How do IR, infrared transmission systems, and RF, radio frequency transmission systems, perform in different environments?
If you want to broadcast in large spaces (especially outside), even on multiple channels, as a rule of thumb radio frequency systems are your best bet.
They provide a strong and reliable signal, which is able to pass through walls and opaque objects. It's the most economical, simple-to-operate choice for churches, auditoriums, stadiums, classrooms and boardrooms. It even works well in the open air. Radio frequency receivers consume more electrical power than the infrared type; therefore battery life is considerably shortened. Finally, with the advent of digital electronics and signaling, infrared has taken the lead with regard to component features -- a lead which is being diminished by some of the new models of radio frequency transmission systems.
With Infrared systems, transmission is confined within opaque walls, making it a good choice for movie theaters, boardrooms, and courtrooms - anywhere privacy is valued. Infrared systems are also immune to radio interference. Receiver management is easier with infrared systems because there is no reason to search for the frequency. However, infrared is usually not appropriate for outdoor use because sunlight generates interference. Power consumption is also quite considerable, however digital electronics offer a wider array of features, in particular auto shut-off mode. Channel capacity is approximately 5 times that of RF. In general, infrared systems are more costly and require more equipment to cover a larger area.
One final note on security issues: radio frequency systems have been unfavorably compared to infrared in the area of security. RF systems are susceptible to interference and can be discreetly intercepted. The later has been a concern in high security situations -- though it is important to note that current technology allows fairly sophisticated intercepts of infrared signals as well. On balance neither system is fully secure -- wireless transmission is by its very nature subject to intercepts -- hard-wired systems are the only way to minimize this threat.
To summarize, if you are looking for portability or there is a need for a system that is easy to setup then a radio frequency system is your best choice. A secondary consideraton is the choice between wide-band and narrow-band wireless FM -- please see our separate research note on this specific issue here.
If you are looking for privacy within an enclosed space or a wider number of broadcast channels, then the Infrared system is commonly considered the best way to go.
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