What is radio frequency (RF, rf)

Radio Frequency

In this post we know what is radio frequency

Radio frequency (abbreviated as RF.rf or rf) is a term used for alternating current (AC) with such characteristics, in which if the current in an antenna ( current) is generated, an electromagnetic field (EM) suitable for cordless broadcasting and/or transmission is generated. 

These frequencies cover most of the electromagnetic radiation spectrum, extending to nine kHz (9 KHz), which is the lowest allocation of wireless communication frequency (this is within the range of human hearing capacity). to thousands of gigahertz (GHz). 

When an RF current is passed through an antenna, it produces an electromagnetic field, which propagates through space. This region is sometimes called the RF region. In technical terms, it is called a radio wave. Any RF field has a wavelength, which is inversely proportional to the frequency. In the atmosphere or outer space, if the frequency is 1 MHz and the wavelength is m, then

s = 300/f

the frequency of an RF signal is inversely proportional to the wavelength of its corresponding EM field. At 9 kHz, the free-space web launch is about 33 kilometers, or 21 mol. At the highest radio frequencies, the EM wavelength is about one millimeter (mm). 

As frequency increases across the RF spectrum, EM energy is found in the form of infrared (infrared or IR), visible, ultraviolet (ultraviolet or UV), X-rays, and gamma rays. Huh.

Many types of cordless devices use RF fields. Cordless and cellular telephones, radio and television broadcasting stations, satellite communication stations, and two-way radio services all operate within the RF spectrum. 

Some cordless devices operate by means of IR or visible-light frequencies, whose electromagnetic wavelengths are smaller than the wavelengths of RF fields. For example, the remote control boxes of most television sets, some cordless computer keyboards and mouse, and some cordless Hi-Fi stereo headsets can be named.

The RF spectrum is divided into several ranges or bands. With the exception of the segment with the lowest frequency, each band represents an increase in frequency corresponding to a power of 1. The table shows the eight bands in the RF spectrum along with their bandwidth ranges. The SHF and EHF bands are often referred to as the microwave spectrum

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Radio Frequency Table

1. Designation : Very Low Frequency

Abbreviation : VLF

Frequency range : 9 kHz - 30kHz

Free space wavelength : 33 km - 10 km

2. Designation : Low Frequency

Abbreviation : LF

Frequency range : 30 kHz - 300 kHz

Free space wavelength : 10 km - 1km

3. Designation : Medium  Frequency

Abbreviation : MF

Frequency range : 300 kHz - 3 MHz

Free space wavelength : 1 km - 100 km

4. Designation : High Frequency

Abbreviation : HF

Frequency range : 3 MHz - 30 MHz

Free space wavelength : 100 m - 100 m

5. Designation : Very High Frequency

Abbreviation : VHF

Frequency range : 30 MHz - 300 MHz

Free space wavelength : 10 m - 1 m

6. Designation : Ultra High Frequency

Abbreviation : UHF

Frequency range : 300 MHz - 3 GHz

Free space wavelength : 1 m - 100 mm

7. Designation : Super High Frequency

Abbreviation : SHF

Frequency range : 3 GHz - 30 GHz

Free space wavelength : 100 mm - 10 mm

8. Designation : Extremely High Frequency

Abbreviation : EHF

Frequency range : 30 GHz - 3000 GHz

Free space wavelength : 10 mm - 1 mm

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