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How do Walkie-Talkies Work?

Ever wondered how those little radio transmitters work? They may be old but they’re still used for good reason. Today, we explain all about walkie-talkies.


walkie-talkies

Walkie-talkies have been around for years, well, since 1937 to be exact. They pre-date the invention of cell phones by almost 40 years. They revolutionized communication and set the path for person to person interaction as we know it today. But, despite being so “ancient”,  their practicality and convenience mean that they are still commonly used. Our prized cell phones rely on nearby cellular towers to send and receive signals, however, walkie-talkies don’t have this weakness.

Learning how this understated piece of equipment works is quite interesting and shows that even with the advent of top-class cell phone technology, there will probably always be a place in our lives for the good old walkie-talkie.


What Exactly is a Walkie-Talkie?

A walkie-talkie is basically a cross between a cell phone and a radio. They send and receive radio signals over distances of up to 40 miles (but only the best models will have a range like this).

You talk into a microphone, and it is heard by the person who is holding the other radio a few meters or even blocks away. The name literally came because you can walk and talk at the same time; this was before the arrival of fancy iPhones and Android devices we all know and love these days.

A walkie-talkie is a pretty old school device, and it can only be used at relatively short range, but it is one of the oldest forms of wireless technology still used today. They are handheld, quite bulky in some cases, and they have a microphone, a speaker, and an antenna on the top.

Recommended Reading: Ever heard of a parabolic microphone? Find out how to make one in our new article.

pair-of-walkie-talkies

There isn’t a lot of privacy involved with using a walkie-talkie, however, because anyone can hear what you’re saying and what the other person is saying on the other end. For instance, if you’ve been to a shopping mall, you may have heard the crackle of a security guard’s walkie-talkie, and you may have been able to hear what the other guy on another level of the mall said in return.

Furthermore, if someone knows on which frequency you are operating, they can receive the messages too, and listen in on a conversation.


How Do Walkie-Talkies Work?

To break it down to its simplest form, a walkie-talkie is a transceiver which is battery powered. It can send radio messages, and it can also receive them.

They use an information transmission system called half-duplex. This means that it can only be used to transmit one signal on a particular channel at any given time. You can’t send and receive a message at the same time. You either listen (receive) or talk (send). This is unlike the cell phone which is full-duplex. It allows data to be transferred in two directions simultaneously and allows us to have seamless conversations free of breaks and interruptions.

walkie-talkie-on-a-person

In order to speak into a walkie-talkie, you need to push a button. This is called push-to-talk transmission (PTT) or press-to-transmit. As you are holding the button you are engaging the transmitter and sending your radio signal. Only one radio on the channel can transmit at any given time. However, multiple units can receive the message. You can’t receive a message when the button is engaged either.

As you let go of the button you are free to hear (receive) any message that comes from another unit that is tuned into the channel you’re working on. You don’t need to dial a button, you’re basically working on a channel of radio frequencies, and that means you don’t have to remember any digits – a plus point.

Most walkie talkies operate within frequencies of 27 MHz and 400-500 MHz. These are called ultra-high frequencies (UHF) and they are way beyond the limits of our hearing. As walkie-talkie signals aren’t boosted by towers, they can also be vulnerable to obstacles like mountains that can interfere with the signal path.

electromagnetic-frequency_spectrum

While a cellphone uses cellular signals, a walkie-talkie doesn’t, so when your cell phone dies because the signal isn’t strong enough, a walkie-talkie will still work. The communication is only short distance, however, but for those working in a large area, walkie-talkies are ideal, and they can also be used up to a few miles away too.

A baby monitor is a form of a walkie-talkie, although only with one-way transmission. This means you can listen to whether your baby is asleep or awake. You can talk if you want to, and you will be able to listen for any sounds or crackles that give you an idea of whether you need to head upstairs and see what your little one is up to.


What is the Future of Walkie-Talkies?

You’d think that such an old technology would soon become obsolete, especially with all the recent advancements in communication in the modern world: e-mail, phones, messaging, video calls. The thing is, this old-school piece of equipment still has many advantages over these methods of communication (as well as some drawbacks too). Let’s take a look at the pros and cons of walkie-talkies.

Advantages

  1. It’s a direct and instant line of communication. There’s no need to wait for someone to answer the phone or read a message. Your message is delivered without you having to wait for a connection.
  2. It doesn’t rely on data plans, Wi-Fi signals, or cellular networks. This makes it perfect for emergency situations or for use in instances where phone signals are unreliable.
  3. They’re cheap to buy and run. When compared to a cell phone which is expensive to buy and then requires a monthly bill to be paid, they are really cheap. Once purchased, there are no running costs.

Disadvantages

  1. The half-duplex transmission only allows one direction of communication at a time. This means you aren’t able to converse freely like with a cell phone. You talk, then when you are finished you can receive the reply. New, top of the range models do actually allow simultaneous communication, but they are very expensive.
  2. The distance that they cover is minute in comparison to a cell phone. While a phone allows communication worldwide, a walkie-talkie is limited to 40 miles at the very most, but usually just a few miles.
  3. The sound quality is not great. The clarity of conversation isn’t as good as with a cell phone.
  4. They aren’t as secure as other methods of communication. If your frequency is known then your messages can be heard. The military avoids this by encrypting their radio communication, hiding it from curious ears.

Despite their obvious flaws, walkie-talkies will always have a place, at least until technology takes another giant leap. The direct, instantaneous delivery of communication is just too convenient in certain applications. Take security staff or the military for example. They need real-time information on potential threats, and a walkie-talkie does this perfectly. They don’t need to press a button to receive information, and they don’t need to worry about the signal disappearing.

Of course, they’re likely to change shape, be streamlined, and change in many ways, but the trusted walkie-talkie is certainly not finished just yet!


If you found this article interesting then I’m sure you’ll love our article on voice-activated audio recorders too!

We recently posted an article on making homemade spy gadgets that’s proving really popular too.

This is an exciting time here at StealthyNinjas.com and new posts will be coming out thick and fast over the coming weeks, months, and hopefully years!

We hope to see you back here soon for more interesting guides and articles.

Image Source: Frequency Spectrum

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