Buying a Two-Way Radio

Two-way radio, also known as walkie-talkies, provide invaluable communication in situations where a cell phone may be out of reach or unable to connect. They’re popular among hunters, hikers and outdoor event planners and are even recommended by family travel specialists for use at sprawling theme parks.

Understanding how these handheld gadgets work is essential for anyone who uses them. Learn about the basics of two-way radio, including the lingo and etiquette.

Buying a Two-Way Radio

When it comes to buying a two-way radio, there are some basic features that you need to take into consideration. two-way radio This starts with identifying what you will be using the radio for.

This will help to narrow down the selection available, especially if you are looking for specific functions such as waterproofing, hand-free operation or long range communication. You will also need to decide whether you require a licenced radio or not. If you do, this will offer many additional benefits including increased functionality and a range that is much higher than those offered by FRS or GMRS models without a licence.

For example, many licensed PMR two-way radios have the ability to utilise repeaters, which will take the transmission from one radio and then broadcast it to a wider area. This will make it possible to communicate over a large distance when the terrain is likely to interfere with the signal.

Other features include power boost, which will increase the signal strength of a radio with the push of a button, allowing you to communicate with workers who are further away or who have been lost. Some radios will even allow you to tune into National Oceanic and Atmospheric Administration (NOAA) weather band channels for local forecasts and hazard alerts, which can be extremely useful in certain industries.

Frequency Bands

There are a number of two-way radio frequency bands available. Your choice depends on what you plan to use your radio for. For example, if your work takes you into buildings, a UHF frequency may be better suited for you because it has a shorter wavelength than VHF and therefore can travel further in-buildings. However, if you are working in open fields or wooded areas where there are few obstructions, VHF might be the better choice.

You also have to consider whether you want your radio to be compatible with other systems, such as public safety radios. For this, you will need a digital two-way radio that is P25 compliant. P25 stands for Project 25 and provides a digital communication standard created by public safety professionals to provide interoperable communications.

Other considerations include what type of battery power your radio needs, how many channels you will need and if it will be compatible with repeaters. A two way radio with repeater capability allows you to transmit on one frequency while receiving on another – this greatly increases your range.

All two-way radios run on battery power and the type of battery determines how long your radio will operate before needing to be recharged. There are a variety of battery types available including Nickel Cadmium (NiCd) and Nickel Metal Hydride (NiMH). Some models of two-way radios come with rechargeable batteries while others require non-rechargeable batteries.

Duplex Systems

When it comes to two-way radios, there is a wide range of options available. They are ideal for many different settings, including schools and colleges where there are a number of students, teachers, maintenance staff and administrators spread across a large campus. This can often make communication difficult and two-way radios are a valuable asset for keeping everyone in touch with each other.

Most two-way radios are full duplex, which means they can send and receive signals using two separate frequencies. This is in contrast to simplex systems that only allow one device to transmit and others to listen. This is essentially how walkie-talkies work, with the speaker having to say ‘over’ or another previously designated word to indicate they are finished speaking and it is safe to listen.

Full duplex systems use separate channels for transmission and reception and can deliver exceptional clarity even at long ranges. This is particularly beneficial for industries that require clear and effective communication in harsh environments or at significant distances.

In data communications, time division duplexing (TDD) emulates the function of full duplex by alternating between transmission and reception on the same frequency. This is two-way radio done by finely chopping the time periods in which each transmission or reception occur, making it appear that devices connected to this system are both transmitting and listening simultaneously.

Antennas

An antenna is the element of a radio system that transforms electromagnetic waves into radio-frequency currents that can be carried on transmission lines. Antennas can be designed to exhibit different performance characteristics depending on their intended application. The most common antenna design is a half-wave dipole. This consists of two 1 / 4 wavelength elements positioned end to end and lying along a common axis (or collinear), each connected to one of the conductors of a balanced transmission line. This arrangement carries currents in opposite directions along the transmission line, and when driven at its resonant frequency generates standing waves with maximum current for minimum voltage.

When an antenna is operated away from its resonant frequency the currents will no longer carry currents in opposite directions, and the resulting impedance seen at the feed point of the transmission line will be out-of-phase with the signal, which will reduce efficiency and output power. The effect can be minimized by matching the antenna to the transmission line characteristics, but this approach still suffers from the usual losses associated with any electrical circuit.

Increasing the height of an antenna can help to overcome this problem, but it may not be possible or desirable to do so for all applications. For example, a stubby antenna that is popular for mobile MURS two-way radio use in many cities can not be used when working in rural areas where the tallest structure may be a tree or powerline, and could be susceptible to interference from nearby objects that would limit its effective range.