A two-way radio’s range of communication

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radio's range of communication

How far can an intercom or two-way radio communications when you are shopping for one? It is difficult to answer this question because it is comparable to saying, “How far up is it?”. The answer isn’t simple or definitive because there are so many variables at play. For a greater understanding of the whole range issue, it is necessary to review radio signal transmission.

In the days of AM radio, you might remember hearing radio stations from hundreds of miles away if you are old enough. Due to the fact that they are reflected off the atmosphere, these signals follow the curvature of the Earth below 2 Megahertz (MHz). In such low-noise environments, AM radio signals can be received by radios hundreds of miles away, even if they are below the horizon.

In general, 150MHz to 900MHz is the frequency range of the two-way radio like Radios Motorola and intercom on the market for purchase. As a rule, radio waves in these frequencies do not travel over the horizon or behind solid obstructions, unlike AM radio waves.

There are, however, exceptions to all general rules. The radio signal can travel through almost anything, even walls and other obstructions, because it travels along “line-of-sight” paths. In spite of the invisibility between antennas, the radios take this as line-of-sight. It is possible for radio waves to bounce off surfaces or reflect back due to reflections, so the straight line between radios may also not be so straight.

Radios are powerful tools

Its power output also plays a crucial role in determining the range at which it will communicate. Watts are used to measuring power output.
Thousands of watts is what most FM radio stations broadcast. One to five watts is usually the range of a handheld two-way radio for business uses. From 5 watts to 100 watts, vehicle mobile radios can be broadcast. Radio can transmit farther if it has more watts.

What does this mean? Water loses pressure as it moves through a pipeline. Current flows down a wire when electricity flows. Rolling objects eventually come to a halt due to friction. It is inevitable that there will be some signal loss along the way since radio waves are subject to the same physical laws as everything else. You will get more distance from all of them if you apply more water pressure, apply a more electrical current, or make the rolling object move faster. Radio signals work the same way.  

The frequency of radio waves

Two-way radios are also affected by the frequency they use and their environment when it comes to determining their range.

Most two-way radios use one of two major formats. UHF (ultra-high frequency) and VHF (very high frequency) radios operate at various frequencies. There is no inherent advantage to one frequency band over another. Every one of them has its advantages and disadvantages. Choosing the right radio for your application depends on whether you want to communicate with other people in one or both formats.

Radio waves are used to communicate with two-way radios. There are different frequencies of radio waves, and you can pick up specific signals by tuning the radio receiver to that specific frequency.

Using VHF radios

TV and radio broadcasts operate on VHF in the same way as FM radio. Commercial VHF radios use the 130 -174 MHz VHF frequency, band.

Line-of-sight factors can affect both UHF and VHF radios, with VHF being more prone. Trees and rugged terrain can get in the way of these waves, but not as well as UHF frequencies do. VHF, on the other hand, would travel almost twice as far if transmitted over an area without barriers. Broadcasting over long distances is easier with VHF.

Especially if you are using a base station radio indoors and you add an external antenna, a VHF radio would be your best choice if you work mostly outdoors. Transmitting and receiving are further away when the antenna is placed higher. Outdoor VHF radios may be used if the area is heavily wooded. It is possible for a UHF radio to transmit more effectively through trees when these conditions exist.

A smaller number of frequencies are also available on VHF radios. Radio interference could pose a larger problem if there are other radios nearby. With the opening of the MURS service recently, the FCC has made this less of an issue. Multi-Use Radio Service is an acronym for Multi-Use Radio Service. FCC regulations apply to the use of this service in the United States and some other countries. RF spectrum in the 150 MHz band is being used for this service, which operates at low power. Each of the five MURS channels has 38 privacy codes to ensure you only hear conversations originating from radios transmitting your code. Users of MURS products are not required to be licensed by the FCC.

MURS allows you to improve range by adding a larger or external antenna. MURS allows you to install antennas on top of buildings or towers. There is a claim that antenna manufacturers will increase a transmitter’s effective radiated power by a factor of four when using an external antenna. Depending on the terrain and antenna height (up to 60 feet above ground), MURS intercoms can transmit up to several miles.

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