The Venerable and Infamous CB Radio, by SonOfThunder

This article is coming by way of SonOfThunder, who’s just started up a blog of his own, the Sons Of Thunder Signal Corps Ministry. I like what he’s doing and even more so that he’s stepped up to the plate.

Some people think CB radio has gone the way of 8-track tapes. Nothing could be further from the truth! The Citizen’s Band Radio Service is as viable today as it was in its heyday during the ’70’s and 80’s. In technical terms, the 11 meter band (how radio operators may refer to it as the wavelength size is 11 meters) can work as skywave propagation as well as groundwave propagation. This means it has versatility in how it is used, as configured by the operator. While often seen as a rough and tumble domain of raucous truckers, hillbillies, and maybe some backwoods travelers, these characterizations really speak to its robust nature, ease of use, low cost, and accessibility.

Before this segment of radio frequencies were re-created by the FCC in 1945 as the Citizens Band Radio Service (C.B), they were in use by militaries around the world. One story I recall involves tank units under General Erwin Rommel’s command, the Desert Fox of the German and Italian North African Campaign during World War II. His tank units used the same frequencies that we now use in the C.B. (the radio then in German tanks was likely the FuG-5 which was considered a ground-wave only radio with a range of 2-3 km when using AM voice, the same modulation the C.B. service now uses; how wrong they were!). Unknown to him or his radio operators, these signals during the campaign were propagating by skywave, and were intercepted by Allied Forces. The transmissions were broadcast in the clear (meaning in plain language without any codes or effort to disguise their meaning) and the Allies used this phenomenon to their advantage.

The range of the C.B. radio like any radio, is determined by how it is transmitted and then how those transmitted radio waves interact with the environment. Even in the bottom of the valley where I live, my C.B. radio installed in my truck can reach farther than C.B.’s typically do. This isn’t by magic but by applying good antenna and radio theory to the configuration.

First of all is the antenna. It is probably the most important component of a C.B. radio as the actual radio technology is pretty standard, notwithstanding buying some suped-up rig or customized radio (this is a very simplified statement that will have to suffice for now). They all run 4 watts off the shelf but how efficiently and effectively those same 4 watts are used is determined by the antenna configuration. A tuned antenna is one which its length is trimmed (the installer literally can cut or adjust the length of the antenna) to a harmonic length of the radio’s frequency. Remember the alternate term for a C.B. is the 11 meter band? Well that’s the key bit of information that informs the size (length) of the antenna. The other determining factor is how big of an antenna one is willing to put on their vehicle or home. You might have the space to put up an 11 meter (36 feet!) long wire in your yard, but most people can’t, and it’s pretty impossible to put one on your vehicle and stay mobile. This serves as an example though of a full wavelength antenna: one that is exactly the length of the frequency wavelength. A (even) harmonic length is one that is divisible by an even denominator, e.g. 1/2, 1/4, 1/8, etc. A radio wave can be transmitted by an antenna that is an even harmonic (and some odd-harmonics, but don’t worry about that now). My truck has an antenna that is 4.5 feet tall. 4 and 1/2 feet is 54 inches. 11 meters is 433 inches. You divide 433 by 8 and you get 54, roughly. This is still a tall but doable length antenna for a pick-up truck. Some have done much bigger 1/4 wave antennas, referred to as a ‘whip’ because it’s a long 9 feet tall stiff steel wire. Cool, but you quickly start hitting things with your antenna and something, usually the antenna, begins to take a beating. To put a fine point on it, the Wilson 1000 magnetic mount C.B. antenna is as fine example of an antenna as reasonably can be obtained and is what I use. It’s easily tuned to 1/8 wavelength, and can take a beating and stay usable with minimal maintenance for years. Mine has.

So that’s it then, the secret is a tuned antenna, right? Not yet. The other component for this C.B. antenna we’re building is the ground plane. The ground plane is an electro-magnetic counter-poise to the vertical antenna. Luckily a pickup truck has one built in: the top of the cab or even camper. This metal ‘sheet’ acts as a ground plane to the antenna, increasing its effectiveness and efficiency. [We’ll have to leave the theory there to limit my brain strain.] When you have used your available resources to create the best antenna you can, then the radio, whatever model/brand you get can work at its optimum. Most C.B. radios on the market, and even the used market which is substantial, have a built in fine-adjustment for the antenna labeled “SWR” . This adjustment is easily accomplished by following the manual’s instructions, and puts the finishing touch on a good C.B. installation.

The actual C.B. radio you put in your vehicle can be a perplexing venture as there are as many makes and models as there are of just about anything else these days. To save time and get to a few good recommendations, I recommend Cobra C.B. radios and Uniden as those are what I have used. There are other good ones out there for sure, I just don’t have as much experience with them as I do the Cobra 29 LX or LTD, or the Uniden Bearcat 980SSB which is what I use in my truck now. The significant advantage of a “SSB” versus a non-SSB CB radio is the single side band simply takes common A.M. signal that all C.B. radios use and cuts it in half. Interestingly, you cut the A.M. signal in half and the 4 watts you have turn into 12 watts as your putting all that energy into a narrower signal. More power combined with an efficient antenna, and now you’ve got a longer range of usability.

So here is the long awaited gist of this article: the C.B. is a cost effective means to communicate over distances that are farther then typical when a little theory is applied to their configuration. I conservatively can hear/talk to almost anyone in my county which correlates to a 30 mile radius centered on my truck, and I live in a complex of mountains and valleys where the valley floor is around 1500 feet elevation and the immediate hill tops are at 4000 feet. Granted I don’t receive equally well in all directions due to the terrain, but it is remarkably better than one would expect. In flat terrain I imagine far better range.

C.B.’s don’t require licensing like Ham radios, are relatively inexpensive, and with a little theory can be installed to have a increased effective range. They run off a 12 volt DC battery, and can go just about anywhere your vehicle can go, the best part being it’s a way to talk while traveling. While not a reliable atmospheric condition, when the D-layer is active (see the “Rebirth of HF” article on this site) I get Superbowl traffic (the free-for-all channel 6) from Louisiana, here in the Pacific North West. No wonder the deserts of North Africa were no match for the active D-layer and the proto-c.b. radio!

As with any radio band (a contiguous segment of radio frequencies such as the FM Broadcast we all know, which runs from 88Mhz to 108 Mhz, or AM broadcast which runs from 500Khz to 1700Khz depending on the country you live in) there are advantages and disadvantages both in the nature of the radio waves and in the hardware used to transmit and receive them. The C.B. provides a robust, relatively low cost, accessible technology that can create connectivity in a community that doesn’t depend on outside technology or agencies. This can facilitate the local church in serving its members both in regular pastoral care as well as in emergent and disaster scenarios. It’s a tool to unify the Body of Christ and to serve Him.