November 24, 2019

Have you caught an interest inradio scanners,radio transceivers, etc. but don’t know how they work or which is the right equipment for you? Well, in this article, we will discuss how radio scanners and radio transceivers work, and how they are different from each other. 

Radio Scanners

The air around us is bursting with radio waves. A radio scanner is an electronic device that acts as areceiverfor these radio waves and lets you tap into the ocean of electromagnetic dialogue. It has the ability to automatically scan or tune, two or more discrete frequencies. A radio scanner stops when it finds a signal or a broadcast and after it ends, the device continues to scan for other active channels.

A radio scanner is also commonly known as a police scanner. Generally, police scanners are used as a communications receiver for monitoring land mobile radio systems that work in thevery high frequency (VHF) andultra-high frequency(UHF) range. However, these devices can also tap into other modulation types such as WFM, FM, AM, etc.

Although earlier models of radio scanners used to be expensive, slow, and bulky, modern radio scanners have improved a lot. Today, radio scanners are fitted with microprocessors that allows them to store thousands of channel and monitor hundreds of channels every second. Some of the recently released models can even decode APCO-P25 digital transmissions and follow trunked radio systems. 

When a scanner tracks police or municipalities in the 800 megahertz (MHz) frequency range, it is known as trunk tracking of computer-controlled networks. 

Types of radio scanners

Radio scanners can be categorized into two types: desktop radio scanners or portable radio scanner. They can be divided further based on their configurations and feature set. For eg., handheld units, home radio scanners, under-dash units, in-dash units, etc. 

Some under-dash scanners which are built into CB radio can not only scan the citizen’s band but may also be able to broadcast to the citizen’s band as well.

Uses of radio scanners

With the help of radio scanners, you can tap into public airwaves that you didn’t even know existed. Radio hobbyists are people who enjoy listening to various types of broadcasts such as air traffic control, fire frequencies, weather broadcasts, or even the local police. Car enthusiasts use radio scanners to eavesdrop driver-crew communications at auto racing events. These are also used by railfans (train buff) that usually scan for specific types of broadcasts.

Radio scanners are used by journalists and criminal investigators to research stories or gather evidence. This is possible because the frequencies they monitor are unsecured and freely available.

Radio Transceivers

A radiotransceiveris an electronic device that contains both a transmitter and a receiver. Thus, unlike a radio scanner that is specialized for receiving signals, a radio transceiver can both transmit and receive signals. Essentially, it is a communication device that makes bidirectional person-to-person communication possible. 

Radio transceivers are commonly known as two-way radio. Depending on their type, radio transceivers can operate on many different frequencies. The frequencies they operate on also varies according to the regulation of the country. Many radio transceivers operate on the very high frequency (VHF) and ultra-high frequency (UHF) range. 

Generally, operators don’t need to tune a radio transceiver to scan for frequencies. They can just tune in to any of the pre-selected frequencies that the device is capable of tuning in to by pushing a button or using a dial. These pre-selected frequencies are saved as channel numbers so that it is easier to use them and remember. However, you will still find amateur radio operators using frequencies instead of channel numbers to communicate. 

The number of channels that a device can support depends on which radio service it’s using. A few common radio services in the U.S include Family Radio Service (FRS), Citizen’s Band Radio (CB Radio), General Mobile Radio Service (GMRS), Digital Electronic Message Service (DEMS), Business Radio Service (BRS), Multi-use Radio Service (MURS), etc. 

Types of radio transceivers

Radio transceivers can be categorized into two broad types depending on how they operate:half-duplexdevice orfull-duplexdevice. Half-duplex radio transceivers are more common than full-duplex radio transceivers. 

Radio transceivers that operate in half-duplex mode use a single radio channel and can either receive or transmit a signal at any given moment. These cannot receive and transmit radio signals simultaneously. So, while communicating, the operators on different ends must take turns talking. By default, the radio transceivers remain in receive mode so that the operator can listen to all incoming transmissions without any problems. For transmitting a signal, the operator has to press the ‘push-to-talk’ button on the device as it turns on the transmitter and turns on the receiver. Releasing the button allows the transceiver to receive signals again. An example of a half-duplex radio transceiver is ‘walkie-talkie’.

Radio transceivers that operate in full-duplex mode can transmit and receive signals at the same time. These devices use two separate radio channels or  channel sharing methods like time division duplex (TDD) to work properly. An example of a full-duplex radio transceiver is a cell phone. 

Depending on their attributes, two-way radio systems can also be categorized as conventional or trunked systems. 

Uses of radio transceivers

Radio transceivers are used for two-way radio communication. Depending on the type of radio transceiver being used and the radio service it uses, the purpose of communication may vary from one individual to another.

The various uses of radio transceivers depending on the radio service they use are listed below:

  1. Amateur Radio Service (Ham Radio) - These devices are usually used by hobbyists for personal communication. Apart from communicating via voice, users can also communicate with text, image, and data by using Amateur Radio Service.
  1. Citizen’s Band (CB) Radio Service - These devices are used for short-distance communication for both personal and business requirements. CB radios support 40 shared channels in an AM or Single sideband mode. Depending on
  1. Family Radio Service (FRS) -  These devices are also used for short-distance, personal and business communications. However, unlike CB radios, these use frequency modulation instead of amplitude modulation.
  1. General Mobile Radio Service (GMRS)- Just like CB and FRS radios, GMRS radios are also used for short-range, personal and business communications. However, you need to have a license to use the devices, which usually covers the whole family. GMRS radios can either be handheld portable devices or mobile and base station-style radios that are used in commercial land mobile bands and public service. 
  1. Multi-Use Radio Service (MURS) - MURS radios are not as popular as FRS or GMRS radios, but these radios are also used for personal or business communication in a short-range. An advantage of using MURS radios is that the frequencies are less crowded. 
  1. Aviation Service (Air Band) - Air Band radios are typically installed inside aircrafts. These act as a two-way communication device that helps the pilot to navigate the terrain better. The range of these devices is longer than land-based radios as the transmission occurs either in air or air to ground.
  1. Marine Radio Service (Marine Band) - Marine VHF radios are commonly installed in both large and small seafaring vessels for ship-to-ship or ship-to-shore communication. Thus, it allows the operator to signal emergency distress calls or maintain contact with marinas and ports. Compared to land-based radio, the transmission range on these devices is longer as transmissions occur over open water. 
  1. Business Radio Service (BRS) - Business band radios are used by both small and large businesses for business communication. These are made with higher quality components and are available in digital or analog mode. Depending on the type, it can support UHF or VHF frequency. License is only required for using certain frequencies that offer greater privacy.