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What is a Two-Way Radio?

Two-way radios are an improvement over one-way communication for long distances. Since as early as the early 20th century, the ability to transmit and receive at a particular location was all in rage. What it did was simple yet powerful. A two-way service allows a location, center, or station to exchange messages wirelessly, not just send messages or receive them. The commercialization of this technology was a bit late, but it was, nevertheless, a game-changer of sorts when it comes to communication back then.

Let’s find out some crucial information regarding the two-way radio so that you have a better understanding of the underlying technology.

  • This will help you when you operate your own CB radio, ham radio, or other radio telecommunication service or station, and
  • This will also help you understand important (and interesting) facts about the entire realm of radio communication in general.

So, without further ado, let’s get right into it.

What is “2-way”?

Two-way, as is clear from that phrase itself, is when there are two channels (in comparison to a single channel). Two channels of communication are essentially receiving and transmitting. Before a two-way radio technology, systems usually had to receive from a set of equipment and transmit from another.

What that meant for a lot of radio services users was that they could either transmit or receive because of physical, technological, legal, or financial constraints. Two-way radio solves all of those problems at once because now you need to set up a single system to both, receive as well as transmit messages.

This is when the “exchange” of information truly came about to be. And the two-way radio was the reason for the revolution that follows its invention. Wireless cross-continent transaction of messages without any bounds and limits. It was truly a dream come true and a pioneering revolution in the field of telecommunications.

Frequencies that two-way radios support

There are a lot of frequencies that the two-way radios work on. As you might already know, frequencies are the mediums on which radio waves travel. Different kinds of services that utilize these waves for radio communication have separate frequency “bands”. These allotments make sure that there is no conflict of multiple services when they try to broadcast their radio signals on the same medium. This greatly helps avoid interferences, noise, and sound distortion.

In different countries, the frequencies are assigned to the two-way radios in different ways.

UHF and VHF frequencies

The radio spectrum is really wide. For optimal functioning, most two-way radio systems work on these two frequencies: UHF and VHF. UHF stands for ultra-high frequency and VHF stands for very high frequency.

These bands are highly competitive, giving rise to the need for governments to manage and regulate them. Most of the broadcasting happens over these bands.

Between the two, UHF has shorter wavelengths. Now, physically, shorter wavelengths enable the signal to escape smaller regions like wall cracks and openings. These are also good for propagation through vegetation.

In contrast, low radio frequencies are good for gaining longer ranges to transmit your signal. So, as up against the higher radio frequency of UHF, VHF enables the transmission to longer distances.

In a nutshell, VHF is really good for outdoors transmission. External antennas on indoor base stations are the most ideal case for VHF usage. The placement of the antenna (and more importantly, the height at which it is) decides how further the signal will propagate. The same goes for the reception of the signal as well.

Also, in the other nutshell, radio services that usually work mostly indoors and inside buildings work best with UHF. There are many smaller openings and shafts in buildings and the shorter wavelengths travel well through these. If you’re interested in the best two-way radios, check this article.

There is one question: what if the building is particularly large? In that case, UHF will lose some of its information or the signal will be feebler when it’s being transmitted over a larger distance. That’s right and that is precisely why the repeaters exist. The invention of repeaters doesn’t just help radio communication. You will often hear of repeaters that “extend” the WiFi range of your network as well. So, a repeater is a device that receives a signal and “repeats” it. This means taking the signal from point A and sending it to point B, thus helping the signal that will naturally end at point A up until point B. Multiple repeaters will increase the range infinitely, at least in principle.

So, services utilizing UHF often resort to repeaters to extend the effective range of the signal.

The importance of channels in eradicating excessive tuning

One of the most important parts of two-way radio systems is a channel. Now, technically, channels are not needed. But think of ice-creams. Ice-creams are nice. But if they come to you, it’s somehow more convenient. Therefore, ice-cream trucks exist. Not everyone wants to go to a Baskin Robbins retail shop all the time.

Similarly, channels merely increase convenience. Technically, we don’t need ice-cream trucks because we can still have the joy of indulging in our ice-cream guilty pleasure. But an ice-cream truck passing through the neighborhood increases the convenience.

Here’s what a channel does, in a bid to increase convenience: Operators need to input frequencies all the time in two-way radios. Channels work as presets of frequencies that an operator might need.

What inputting frequencies mean is essentially “tuning.” Now, you might know about tuning. Here’s a brief overview to brush-up your memory: tuning means setting-up your device (especially the antenna) to capture signals from a particular frequency. When you need to get on a separate frequency, you “re-tune” your equipment for that frequency so that you can capture signals on that one, and transmit over that one too.

Channelizing helps in eradicate the need to tune all the time. This is a very important feature that most of the beginners don’t appreciate or understand much about. Without channels, you will lose interest in running your radio system quite quickly.

William

This article is written by William Johnson, the founder of RRD. William is passionate about radar detectors. His interest in reviewing and testing radar detectors from different brands started nearly 10 years ago, when his own radar detector then (a cheap and brand-less detector he bought online) failed to detect and radar gun nearby.
William

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