A Primer on Radio Communication

Introduction

Few things are taken as for granted by as telephone communications. These days, with most people reliant on cellular service, the potential to have communications disrupted is as prevalent as it has been since telephones arrived in almost every home. The author personally has been in major metropolitan areas where cellular towers have been overloaded and gone down, usually due to a major natural disaster (think the Moore tornado of 2013 or the Nashville flood of 2010). Landlines can be overwhelmed as well, but how likely are you to be at home when a major emergency happens? When everyone is either trying to call for help or call others to let them know they’re ok, there are only so many usable frequencies (or channels in layman’s terms) available for the cellular devices to connect to. With that said, reliable alternatives do exist, and that’s what we’ll be discussing today.

There are a number of methods with which to communicate when cellular (or even landline) service is unavailable. Some of them are often used for local, short ranged communications when telephone service in general is not available. Others are capable of longer range and more suitable to communicating across a state or region. We’ll start with the shorter ranged methods and work our way up.

Citizen’s Band (or CB)

After the invention of the CB in 1945, the FCC quickly allocated frequencies for that use. In the 60s, as solid state radios came into the mainstream, the prices for these radios dropped quickly to the point where the average citizen could afford them. With this, the “CB craze” was on, and continued throughout most of the 1970s and into the 1980s. Originally 23 channels, within the 27MHz (aka the 11 meter) band, this was later expanded to 40 channels. Ultimately, two of those channels would (and still do to this day) get the bulk of the use. Channel 19 is the “main” channel that you’ll be able to hear on the highway. Truck drivers, such as the author, often use 19 to get weather reports from drivers coming from the other direction, as well as reports for traffic and where cops are sitting on the highways and byways. Channel 9 has been universally designated as an emergency channel. Most state highway patrols and state police still monitor Channel 9, even though the days of non truckers having CBs in their vehicles are largely gone.

CBs are generally reliable within 2-3 miles. The FCC has limited them to 4 watts of output power, although that rises to 8 watts if Single Sideband (or SSB) is utilized. Being amplitude modulated (or AM), voice quality is serviceable, although not nearly as ideal as FM, let alone some of the digital modes available in other forms of comms. CBs are good for convoys, where the people you need to communicate with are close by. They’re often used within the off road community for this reason. Anything requiring more range than 2 miles will need to resort to other forms of communication. With that said, we highly recommend any CB that is purchased has some form of “weather alert” capability. Many CBs on the market offer the ability to receive on the NWS weather radio frequencies. Some will automatically click over or otherwise alert you when they receive the sub audible tone transmitted with a severe weather warning. This can be invaluable when something unexpected happens.

The author personally refuses to buy a CB that does not have that capability.

Family Radio Service (FRS) and General Mobile Radio Service (GMRS)
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‍While technically different from a regulatory standpoint, we lump these two together because they are both FM modulated, and operate within the same frequency range (or band). FRS frequencies are what the walkie talkies from the sporting goods store operate on. While they “claim” some obscene communication range (we’ve seen them claim as far as 35 miles or 56km), being limited to 2 watts of output realistically limits range to 1-2 miles. From a pragmatic standpoint, FRS is really no better than CB, except that the voice quality will be better with FM rather than AM modulation. This is where GMRS comes in. On Channels 1-7 (shared with FRS), GMRS is allowed 5 watts of output rather than 2. On channels 8-14, there’s no benefit, as both are limited to 0.5 watts. GMRS is allowed 50W of transmitting power (and the use of repeaters) on channels 15 and above, but they’re not widely used outside of a handful of major metropolitan areas.

For FRS, no license is required. Buy the radio, pick your channel and (if you so choose) privacy code, and start transmitting. Privacy codes are what’s also known as CTCSS or PL tones. They set your radio to hear only other radios transmitting that same sub-audible tone. They’re totally optional, but can be desirable if you don’t want any interference from others operating on the same frequency. For GMRS, a license from the FCC is required. There is no test involved, but it does require a $70 fee, and it remains valid for 10 years once granted. This license also covers family members as well. This is becoming a more popular means of communication among off roading groups, and to a lesser extent, as a short range, simplex communications among storm chasers. The same privacy codes (PL tones) apply to GMRS as well.

Amateur (aka HAM) Radio

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We will ultimately cover amateur radio specifically in a future article, as there is such a wide range of nuances and aspects that simply cannot be covered in a general overview of radio communications. Ham radio covers an enormously wide range of frequencies (all with different characteristics), and a number of voice and data modes. Suffice to say, if it can be encoded in a manner that can be transmitted, and decoded on the other end, the possibilities are immense. For local communications, most hams operate on VHF (6 and 2 meter bands) and UHF (in this case 70cm, although 23cm can be used as well). 2m and 70cm make up the bulk of repeaters within the United States and Canada. During severe weather events, SKYWARN volunteers operating on these repeaters receive reports from storm chasers (such as the author), and relay those reports to the National Weather Service office in their area. These reports are invaluable to the NWS as they try to warn the general citizenry of impending threats from severe weather. If you hear the NWS or the TV news say “spotters report seeing….”, that report likely was transmitted via amateur radio. There are a number of radios to choose from; everything from 5 watt handhelds to 110 watt mobiles on VHF and UHF.

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Beyond this, there are what’s referred to as High Frequency (HF), Medium Frequency (MF) and Low Frequency (LF) bands that are capable of communicating over far longer distances. Most amateurs licensed at General or Amateur Extra (or Advanced in Canada) have used HF frequencies at some point or another. SSB and AM voice, various forms of data, as well as Continuous Wave (CW, aka Morse Code) are all transmitted via HF and MF bands. Due to the characteristics of the wavelength, these signals will “skip” off the ionosphere and return to earth, allowing for long distance communications. After Hurricane Maria, 80 and 160m bands operated by hams were the primary means of communications from Puerto Rico to the Mainland United States, due to internet, satellite, and telephone based communications being rendered inoperable due to the severity of the storm. This is ultimately the purpose of the Amateur Radio Relay League (ARRL) in the US; to provide communications to assist local authorities during emergencies. With these bands, most radios run out to 100 watts, but there are amplifiers available to bump power up to as much as 1500 watts. Recall, if you will, the movie “Independence Day.” During the scene that panned between Brits and Israelis, and later Russians and Japanese, receiving the plan of attack via Morse code, this was almost certainly done via amateur radio, as most governmental agencies have all but abandoned their HF and lower capabilities.

While there is no cost involved in many cases to obtain an amateur radio license, there is a test that must be passed. In the United States, there are three levels of licensee. Technician allows an operator to utilize bands 6m and shorter (or higher in frequency), and allows limited privileges on the 10m band. After obtaining General, an operator is allowed most of the HF and MF bands, and can be a Volunteer Examiner (or VE) to administer the Technician test after being accredited. Amateur Extra opens up all amateur frequencies allowed in the US, and also allows full VE privileges to test candidates for all levels of license. In Canada, there is Basic and Advanced. Basic is very similar to Technician in the US, although passing the Basic test with an 80% score (Basic with honors) will allow use of HF bands, much like General in the US. Advanced is essentially equivalent to Extra in the US, except that in Canada it’s required to have Advanced to build your own equipment or operate a repeater or sponsor a club. In the US, the test for Technician and General is a 35 question, multiple choice exam, and Extra is 50 questions, also multiple choice. In Canada, the Basic and Advanced are a 100 question and 50 question test, respectively, also multiple choice. The downside with this is that each operator has to have their own license, unlike GMRS, where an entire family is covered under a singular license.

Scanners

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We will touch briefly on this as these can be useful at times. While they do not transmit, they allow someone to keep an ear on what is happening in their general vicinity. Most governmental agencies are on some form of trunked radio system these days, with most of those on some form of digital voice. During severe weather events, listening to local Emergency Management Agencies is invaluable, and many of the more rural public safety agencies will operate as storm spotters during those events.

We can’t give a singular recommendation due to the variances in radio systems between localities. Even areas where the author has lived provides different variances. With that said, nothing less than a digital capable scanner will do in most cases, and some of the older digital scanners won’t be adequate in some cases. Radioreference.com will provide an enormous amount of information on radio systems in your area. Unless there are P25 Phase 2 systems either already active or planned in your immediate area, a scanner such as the GRECOM PSR-500/600 (or equivalent Whistler WS-1040/65) or the Uniden BCD996XT/396XT or earlier will suffice. There are also Radio Shack branded scanners available that are based on these scanners. If there are P25 Phase 2, Provoice, NXDN, or DMR systems prevalent in your area, then you are essentially limited to the Uniden BCD 536HP/436HP, BCD996P2/325P2, and the Whistler TRX-1/2, depending on your preference for base/mobile mounted or handheld.

Also worth noting is that police are transitioning to new bands which are not picked up by many current scanners.

However, digital software such as 5-0 Radio can be downloaded to your mobile device free.

Conclusion

As we’ve demonstrated, there are a myriad of methods for communications if telephone service is not available. Everything ranging from a few miles all the way to thousands of miles. Each method that we’ve outlined has advantages and disadvantages, and ideally each should be incorporated into our overall capabilities. Not only should we have radios of each type on hand, but we ultimately should use them enough that we can use them comfortably. The author in particular has used each of these methods, with a number of fixed, mobile, and field setups. In fact, Amateur Field Day, held in July, as well as the Winter Field Day held in January of each year, are events where hams across North America in particular, and the world even, set up in varying locations to test their skills. This, in addition to utilizing scanners, will allow one to maintain awareness with what’s happening during various emergencies, as well as being able to maintain reliable communications with others who can help, and vice versa.

Best to everyone,

Drew

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Drew is a 12 year veteran of the US Army who has had a lifelong fascination with weather and the outdoors. Growing up in Northeast Oklahoma, he learned at an early age how to work with cattle and horses, and began riding even before he was tall enough to climb up himself. During his time in the Army, he gained experience in mounted operations and in logistics as part of Armor and later Cavalry units, as well as managing communications under operational conditions. A long time HAM operator and veteran storm chaser, he’s observed and called in numerous severe weather events, is a member of ARRL, and active within local ARES and local ham radio clubs.

His interests include working on various types of vehicles (both old and new), shooting, archery, sports medicine, martial arts, weather forecasting/chasing, and radio communications (especially with regards to emergency management). He also enjoys photography (both digital and film), as well as working with computers. He has a special affinity for the land stemming from childhood, and enjoys hunting and fishing, in addition to working with horses and cattle.