This article replaces the old "CB Radio Primer for 4x4s", written in 1998. If all you want is CB radio information, you can skip this article and read the CB Primer instead.
The purpose of this article is to present and discuss the various options for communicating in the back-country. I understand that most four-wheelers aren't concerned with the hows and whys, and are merely looking for ideas and recommendations, so I've attempted to create an in-depth article while keeping it relatively non-technical. When I first started writing it, my intention was to make it a quick, basic guide. After a couple days of revisions, it evolved into more of a crash course containing practically everything I could talk about relating to 4x4 communications. I've realized that sections of it start to sound fairly technical, but I think that most people can understand what I'm trying to say.
I have worked in the radio-communications industry in the past, both in managing the two-way radio division of a communications company, and in selling and installing commercial two-way radio equipment. As a hobbiest, I am an Advanced-class amateur radio operator, and I've been refining the communications systems in my own 4x4's since 1987. I don't pretend to know everything, and some people may disagree with some of my ideas and opinions, but this is based on my own experience.
Extreme temperatures are also an issue, as we can be travelling through a scorching desert in the middle of summer, or we could be stuck in a high-altitude ice storm in the dead of winter. I had an LCD display freeze up on one of my radios during a winter expedition; as a result I had no idea what frequency I was on.
I've found dust to be a major killer of radios. Although the problem can sometimes be easily fixed by an application of compressed air, consumer-grade radios tend to die quickly, and I've had several CB's fail because of this. As a result, I no longer have a CB in my truck, because I can't rely on it.
Moisture is another unavoidable aspect of four-wheeling. If your 4x4 of choice is an open-top vehicle, consider mounting the radio into the dash with a marine anti-splash cover that flips up to allow access to the radio controls, and even an upgrade to marine speakers for your stereo. If you're like me, mount your radio up high so that when the water comes pouring in through your so-called door seals, you'll still be able to holler for help. Some radios are inherently better at fending off water, and some can be helped with the application of silicone sealant along the case edges. Microphones and speakers can be made splash-resistant by sandwiching a piece of your wife's nylon stocking between the front of the microphone element or speaker, and the case grille.
Physical terrain is another consideration. If you are travelling in a wide-open desert and require long-range communications, a high-gain antenna, which is physically long, is desirable. If your primary terrain includes overgrown trails with low-hanging branches, a physically shorter (and thus lower gain) antenna should be used, along with a shock spring.
The type of communications gear we select is dependent on whom we need to contact. Simple nearby truck-to-truck communications can be done via CB or FRS; longer ranges require better equipment. Telephone communications is unreliable at best; while most cities, towns, and major highways have some sort of mobile telephone coverage, many of the areas that we travel in do not. The exception is satellite phone, which is fine if you can afford it or if your company has provided one to you, but the cost is generally beyond the financial grasp of us mere mortals. Cellular service exists at most major urban areas and along much of BC's highways, but even your selection of cellular provider can determine whether you can make a call or not.
Some CBs use LCDs (liquid crystal displays) instead of LEDs (light emitting diodes) to display the channel number; I prefer LEDs to LCDs as I have had LCDs freeze up in cold weather. Those of you in warmer climates may not have to worry about this.
A good deal can sometimes be found on used radios, although the usual
caveats apply. Models to watch for include the Cobra 138XLR, President
Grant (old board) and Thomas J., Realistic TRC-449, TRC-450, TRC-451, Cobra 146GTL, and pretty much any 28-series and 29-series Cobra radio. Beware of buying a used radio from an unqualified individual who thinks he's a CB technician; these radios are frequently "screwdrivered" in an attempt to garner increased power, which frequently results in detuning the radio and can result in your transmissions causing interference to other services via "harmonics" (numeric multiples of your transmitted frequency), such as public safety and television.
In some countries, "export CB's" are available; these have added
features such as as FM (frequency modulation), more channels, higher power, etc. Many of these radios are marketed as 10-meter ham radios, easily modified for CB. Some models include Cobra 148GTL-DX, RCI-2950, President Lincoln, President Jackson, Uniden HR-2510, and others sold under the "Galaxy" and
"Superstar" brand names. Almost all of these radios are manufactured by
Uniden, and are the same size as the Cobra 148GTL. In Canada, it's illegal to use these radios on CB frequencies.
Speaking of illegal, don't bother with a "linear amplifier". These amplifiers are designed to increase your transmit range by boosting your RF power output. The problem with that is for close-in use on the trail, you will sound muffled to everyone within several kilometres, so it's useless for our purposes. In addition, cheap "CB" amplifiers do not incorporate filtering, and greatly increase the potential for harmonic interference.
In Canada, CBs are license-exempt.
Note: In Australia, there are two types of CB radios. They have the same 27 MHz units that we have, and they also have a 40-ch UHF CB service that operates in the 476-477 MHz range. The UHF CB's are very popular with local emergency organizations, and some have repeaters set up for increased range. As usual, the 27MHz CBs use AM (Amplitude Modulation), and the UHF radios use FM (frequency modulation), which basically means that the UHF CBs are much clearer than the 27 MHz CBs.
Motorola FRS radios are available very inexpensively on Ebay; I've seen daily listings for refurbished high-end Motorola units for US$9.99 each, and brand-new high-end Motorola units for around US$40-70 per pair. Motorola even sells directly on Ebay; look for the "Direct from Motorola" logo in the listings.
Most Motorola FRS radios operate on 3xAA 1.5v batteries; you can buy a pair of nickle-cadmium rechargeable packs and a two-unit charger for around US$20.00 new on Ebay. If you are planning on using your radios in a cold-weather environment, I suggest using alkalines or lithium-ion rechargeables, as nickle-cadmium batteries tend to fail in cold temperatures. Also, it wouldn't hurt to have a spare set of alkalines on hand, in the event that you're out late and cannot recharge your rechargeable batteries.
Garmin has come out with FRS radios with GPS built in; their "Rino" units have the ability to send their GPS coordinates over the airwaves to other Rino radios. I have not tested these units and cannot say how well the FRS portion performs.
In Canada, FRS radios are license-exempt.
Note: Americans also have access to the General Mobile Radio Service (GMRS); these radios operate on frequencies similar to FRS, but the radios are higher power and require licensing from the federal government. Although some frequencies are identical and communications between the two services is physically possible, cross-service communications is illegal.
VHF radios require a license and frequency assignment from the federal government. If you wish to have additional frequencies in your radio, you generally require a letter of approval from the licensee of the frequency. License fees are charged on a per-radio basis, not a per-frequency basis. IT IS ILLEGAL TO USE OR POSSESS A VHF RADIO WITHOUT A VALID LICENSE.
Due to the complexity of the hobby, prospective Amateur Radio operators must pass a written test and become licensed by their country's federal government before they can possess or operate a ham radio. The test consists of radio theory, electronics theory, and rules and regulations; study guides are available from most Amateur Radio clubs and Amateur Radio stores.
Note: It is illegal to use ham radios on commercial frequencies (ie. outside of the Amateur bands), except in emergency situations.
CB: Much of the relevant info on CB antennas has already been covered in the "physical characteristics" section above. In addition, I recommend the use of a steel whip rather than a fibreglass antenna; fibreglass antennas tend to crack or shatter when repeatedly struck by branches at speed. Also, when purchasing a CB antenna, don't bother with "cellular look-alike" antennas; they do not perform nearly as well as a "normal" antenna, and the open coil in the middle of the whip can snag leafy branches. Finally, don't waste your money on a "dual antenna" setup (known as "co-phased" antennas); while the truckers may like the look of dual fibreglass antennas on their mirrors, the antennas must be spaced 102" apart to work properly, and dual antennas can be difficult to "match" (tune to your radio). The money you save by not buying a second antenna and a special coax harness can be used for something useful, like more tools. :)
VHF, Autotel, Mobiltel: These services operate on similar frequencies, so the following notes apply to all three services. The most popular antenna is the 5/8-wave high-gain antenna, which has a small coil at the base and a steel whip approximately 49" long (varies with frequency). I've been talking about "loading coils" in the past which electrically lengthen the antenna; this particular coil is actually a "phasing coil" instead, which is needed because a 5/8-wave element is not resonant and without it, the antenna would be "out of phase" (just in case you were wondering!). A 5/8-wave antenna typically provides a gain of 5dBd. For short-range or in-town use, a 1/4-wave antenna is popular; this antenna is approximately 14" long and does not require a coil (because a 1/4-wave element is resonant). A 1/4-wave antenna has "unity gain" which essentially means 0dBd. Both of these antennas require a proper "ground plane", which is a metallic mounting surface whose radius is equal to a 1/4-wave element, or 14". If your mounting situation is such that an adequate ground plane is not available, ie. a motorcycle, ATV, or fibreglass body, a 1/2-wave antenna can be used. A 1/2-wave antenna resembles a 5/8-wave antenna, but does not require a ground plane, and has unity gain. When used with a ground plane, a 1/2-wave antenna typically provides a gain of 2.5dBd. When operating at VHF frequencies and above, do not transmit when somebody is located within 3 feet of the antenna; doing so can expose them to a dangerous amount of RF energy.
Note: Amateur Radio antennas that work on two or more bands are available, such as VHF/UHF. These antennas typically have two or more coils, and provide less gain than a dedicated single-band antenna. The reason for using one of these antennas is so that your vehicle doesn't resemble a porcupine; for instance, I have one radio in my truck that covers VHF, UHF, and 800 MHz; Larsen makes an antenna that covers all three bands and is the size of a high-gain cellular antenna, so instead of having to mount three separate antennas, I can have a single low-profile antenna that doesn't attract as much attention.
HF: HF antennas are typically very long. Some are similar in size to the 102" steel CB whip, others have a large loading coil in the middle of the whip, and others have a fibreglass lower section with a steel whip on top. Most commercial HF radios come with automatic antenna tuners, thus freeing up the user from having to "match" the antenna to the radio. This is especially advantageous because of the range of frequencies that HF radios cover, which would otherwise necessitate matching the antenna every time the user changed frequencies. With an automatic tuner, the user merely pushes a button and the antenna is tuned within a few seconds. I have this feature on my Kenwood HF radio, and it's great. A friend of mine in the Vancouver area with the same radio once tuned up a garbage-disposal bin on the 20 metre Amateur band, and talked to a ham in California. :)
Try to use heat-shrink tubing instead of electrical tape to cover your wiring connections; tape has a nasty habit of unravelling and leaving a sticky residue. Heat-shrink is more durable, and makes for a professional-looking installation.
