Radio Frequencies - What Do They Mean and Why Are They Important?

Posted by Rahsoft RF Certificate on August 16th, 2019

One of the most popular services using radio frequencies is terrestrial or satellite broadcasting. Radio and television are a well know and established way to send picture and sound with radio waves. Because we usually want large coverage areas with few transmitters we are using high power transmitters on high transmitting sites. Large coverage areas also mean coverage across the border.

Before radio communication can be received, it is necessary to have an antenna in place to pick it up. However, since an antenna cannot distinguish between the thousands of signals that it will pick up at the exact same time during use, a tuner is needed to narrow down the source of the signal. RF Technology Certification Online

A tuner will help you to tune in to a specific frequency, which will in turn help you control what "channel" you are dialing into and picking up with your antenna. The tuner usually makes use of a resonator that amplifies oscillations of the desired frequency to a point where they are distinguishable over the rest of the "noise".

RF energy is also used in the medical field. For example, some minimally invasive surgeries make use of RF energy for coagulation and radio frequency ablation. This, for example, can be used to treat conditions such as sleep apnea. RF Certification

Because radio waves travel across country borders and may interfere with other radio waves there are many rules, frequency plans and procedures that define how to use radio frequency spectrum to avoid interferences. Because different frequencies have different properties there are some general harmonized frequency bands that define main purpose of the band and basic technical parameters of transmitters using these frequencies. The so called allocations are accepted on international levels and provide basic rules for frequency usage. Each allocation is then further refined and countries may have special agreements on how to use specific frequencies.

This is a very important fact because in the same area there can be only one transmitter that can operate on a particular frequency without causing interference. Of course, there are special cases like digital broadcasting and single frequency networks where nearby transmitters operate on the same frequency without causing interference, but for analog broadcasting careful frequency planning is a must.

For broadcasting frequency bands there are many special regional agreements that very precisely define particular frequencies allocated to each country, procedures to be used to modify the plan and also many rules that have to be respected to avoid interference. how to become an RF Engineer

When we would like to listen to a particular radio we need to know the frequency on which this radio broadcasts. A frequency is like a street address where each house has its own number. For television the same applies. However, for practical reasons we usually do not operate with frequencies directly but we use channels where each channels number represents one (central) frequency with some channel bandwidth.

In general, most consumers are not aware of all the technical details that regulate frequency usage and are used to provide many wireless services. They only expect good music, quality movies and mobile phones that work anywhere.

RF electrical currents also display a very interesting set of properties. For example, RF currents can ionize air and create conductive paths right through it. Another example lies in how RF electrical currents travel along the surface of conductors instead of penetrating through...aka the "skin effect".

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