Ressources

Mankind has relied on various forms of communication through the ages. Our ability to communicate effectively is what has really allowed us to become a global society. As a global village we’ve only been able to accomplish this with our ability to communicate over vast distances in very short periods of time. In this series we’ll be discussing how this has all been enabled by RF and this whole field is barely 200 years old.

Just over 200 years ago Hans Christian Ørsted was busy with an experiment where he passed electoral current through a conductor and noticed a compass needle a distance away deflecting later, Faraday proved the opposite is also true, if he were to alternate a magnetic field, he would induce an electric current. All of these lay the foundations for what is now known as Maxwell’s equations, the unification of electricity and magnetism and this brings us to the next step, what is RF?

Communication systems rely on your ability to transmit information. Action at a distance, the phenomena first observed by Hans Christian Ørsted over 200 years ago, is the basis of our communication systems these days. RF is really just a subset of the electromagnetic spectrum and it is the frequencies which have been found to be most suitable for telecommunications purposes.

Making use of RF for telecommunications systems relies on transmitting antennas and receiving antennas. Now, you may have heard of the near field and the far field before. Well, the near field is really the area about a transmitting antenna where there is large amounts of reactive energy. Really, where the relationship between the electric and the magnetic field are not yet fully established. the far field is what we use when working with power densities for a receiver. It is really important to understand all these fundamental characteristics of electromagnetics to make effective use thereof.

When working near transmitting antennas the power densities you may encounter can easily exceed the safe working limits as one of the side effects of RF is its ability to heat biological tissue these levels need to be kept in check.

Transmitting antennas are more ubiquitous than you may realize. Professions such as HVAC, waterproofing and window washers are very often up on base stations not realizing it. Anybody who works near transmitting antennas should be taking necessary steps to ensure their levels of exposure are within the safe working limits.

The strength of RF is also its weakness we have no inbuilt sensor which allows us to quantify the levels which we’re exposed to. Those working around transmitting antennas, where the levels may exceed the safe working limits, really do need to have some way of quantifying these to ensure they are not in harm’s way.

To avoid overexposure to RF the accurate assessment of the levels present in the environment in which you’re working is really important. This is accomplished through the use of a personal RF monitor. These devices are specifically designed to correctly assess both the E- and the H-field and also all the sources present around these transmitting antennas and reported to you in terms of the safe working limits. This way you will know as you begin to approach these limits or even exceed them allowing you to take the necessary corrective actions in time.

As our dependents on telecommunications has grown so too has the need to convey more and more information using the same scarce resource with electromagnetic spectrum. This is brought about the evolution of the communication protocols we use. What originally started as a cell phone in 1973, the first iPhone in 2007, and right now we’re up to 5G handsets able to convey vast amounts of data in a very short period of time we can only imagine where this is going. This is becoming the basis of our economies and will be for many years to come.