Then Truth Behind
the Marketing Claims
The Mystery of Range is Revealed.

...GMRS marketing claims associated with range aremisleading and outrageous.

by Doug Smith

You read it on the side of the product boxes, and in the newspaper advertising and catalogs. This radio will transmit with the "full legal power" up to 5 miles, 2 miles, 3 miles, 7 miles, 12 miles, even 25 miles! How do they know? How does your radio's output power effect range and clarity? Will this radio work in my five-mile application? Well, maybe. I do not mean to be facetious, I really mean maybe. In most cases, probably not, Probably not even close.

What the marketers do not do is explain to the consumer the laws of physics as those physical laws apply to the propagation of radio waves. These are the same laws of physics that apply to FRS and GMRS and to any wireless device. Your cellular telephone is also a wireless device. In fact it is a very sophisticated two-way radio. Each type of wireless device or system operates under different human-designed configurations that take advantage of physics to manage range, clarity of reception, and performance. Each design has strengths and each has its limitations.

The Simple Answer Please
"I don't have time to read all of this."

"The range specifications on some FRS and GMRS radios are true for unobstructed line of sight communication. A one-half watt FRS radio can be heard at a distance of two miles. In most consumer applications while traveling and vacationing, the reliability (clarity) of communication is probably best within one-half mile to one mile. The altitude of the sender or receiver within the terrain makes the difference."

"A higher-powered GMRS radio, from 3 to 50 watts can communicate reliably over a much greater distance and through vegetation and around obstructions. You can expect from two miles to tens of miles depending upon the radio you select."

"The range of GMRS radios using repeater capable radios can be far greater than using a hand-held radio or vehicle radio communicating using simplex."

The FCC Says

At the FCC website they tend to be conservative and in our mind mostly right on about the useful range of each Personal Radio Service. We think the GMRS figure should be reduced to 2 given the introduction of low power hand held radios to GMRS (two watts or less)

Primary Factors

The primary factors affecting your range using Family Radio Service and General Mobile Radio Service devices are:

1. The output power of the radio. The more output power the stronger your signal will be. Physics professors express the relationship between output power and range with an inverse square ratio. There are diminishing returns. You have to quadruple the power to get twice the distance in a given set of conditions. When you have terrible coverage with one half watt quadrupling your power to two watts might help. We say might because if you are surrounded by vegetation or hilly terrain all the increased power will do is give you better clarity in the areas where you can already be heard and not much of an improvement on distance.
2. The height of the transmitting and receiving antenna connected to the radio is far more important than power. Because UHF radio is considered a line of sight radio frequencies band, the higher you can get the antennas the more likely you are to be heard. A one-half watt FRS radio can be heard over thirty miles away when used on a 4000-foot mountain. Just holding the antenna of your FRS or GMRS radio looking toward the intended receiver as high as you can will improve range or at least the likelihood your signal will be heard. Get your antenna in the clear and away from your body. If you must wear a radio in a jacket pocket turn your body toward the direction you want your signal to travel. Even your body can block the radio signal and effect your ultimate range.
3. The position of the antenna relative to the Earth. Is the antenna horizontal or vertical. This is called horizontal or vertical polarization. If you hold the antenna horizontally, you can dramatically reduce the received signal strength at the other end (by half or more) if the other end has a vertical antenna. Both transmitter and receiver must have the same orientation all of the time to facilitate greater range and clarity.
4. The terrain and vegetation between you and the intended receiver. If you are in a gully or a ravine or in a valley surrounded by hills and mountains you will not communicate well or at all with persons not in your immediate area.

Keep in mind the UHF radio waves used by FRS and GMRS, are at frequencies which provide the clearest communication within line of sight of the intended receiver. If you can see the receiver, the receiver may be able to hear you under most circumstances. If you place a mountain, a hill, or large building in-between you and the receiver, the transmission is attenuated. The received signal will either disappear or not sound as clear. Once you have some experience using these radios, you learn what does and does not work. You learn quickly that the GMRS marketing claims associated with the range of twenty-channel bubble-pack radios are misleading and outrageous.

The Difference between
Cellular and FRS/GMRS

We are dealing with apples and oranges here but that is just the point. As a user of a cellular telephone, you are probably wondering if a GMRS or FRS radio behaves the same way or differently. Perhaps the comparison will help you better understand the applications for both wireless devices in terms of how your family will use each one.

Cellular

Cellular telephones work at much higher radio frequencies. (800 MHz and 1900 MHz) These radio frequencies are very-line-of-sight radio frequencies. Your cellular telephone is a very low power device designed to work with thousands of cellular sites. The telephone companies put thousands of cellular antennas in metropolitan areas so you are theoretically never out of range of a cellular receiver, probably less than a half mile in many cases. There may even be cellular panel antennas inside buildings and tunnels so your cellular coverage is seamless and uninterrupted as you travel. Even so, you must cope with the same laws of physics. It is just more likely that the configuration of the cellular system has mitigated many of the problems associated with obstructions, distance, and how your hold the antenna. The signals are so much better and more reliable because the telephone companies planned it that way.

Two-Way Radio

FRS radios and GMRS radios communicating with each other on the same frequency do not use a system to enhance communication range. The quality of the receiver, transmitter output power, the height of the radio antenna, obstructions including vegetation, and the distance between users limit the success of using these radios. When the marketing message on the radio box says there are no subscription fees what they are really saying is that, your two or more FRS or GMRS radios are the system. You do not depend on anyone else but yourself for transmission clarity or success. You control when you can and cannot hear your partner taking into account how efficiently you use your radio and where you use your radio. The milage claims are simply misleading marketing hype designed to fool you into buying the radio.

Our Radio Reviews

In our early reviews of FRS radios, we did not rate the range of each radio. That puzzled some readers. We didn't do it because it just does not make sense to do it given the variables involved. The slight difference between radio output power and the minor efficiency differences between antennas on these radios will not appreciably make any radio better or worse as far as range goes. There was only one FRS radio where this thinking did not always apply and that was the now discontinued Radio Shack mobile FRS radio. This radio positioned the antenna outside the vehicle and the antenna was not an inefficient rubber- duck antenna. Radio Shack used a standard quarter wave antenna which made more efficient use of radio's available power. This radio was much more capable of achieving reliable distances of from 1 to 1.5 miles in most situations. Radio Shack however advertised a very misleading maximum of three miles. I own two of these and NEVER achieved three miles in a vehicle environment until I talked to another FRS radio on a 3800 foot mountain 14 miles away. Most people buy these radios to talk to others within a traveling group and not to others on mountain tops.

We think the consumer should care about features that make operating the radio work under their intended application. This is discussed at length on our review pages. Do not bother yourself with range issues. Unless the radio you are buying is not working as advertised the reliable range of the radios should be as described in this article.

GMRS Using Repeaters

The range of a GMRS radio using repeater-capable radios can be far greater than using a hand-held radio or vehicle radio communicating using simplex. A repeater is one additional item that can be added to a GMRS system to increase range. A mountain top or tower based antenna receives your signal and repeats it in real time over a far greater area of land. It is an artificial way of getting the antenna on your portable radio or vehicle radio much higher so you can communicate over a greater distance.

My family uses a radio repeater located at my home. Going one direction we have trouble hitting the repeater from fives miles away using a forty watt radio. The other direction across the Chesapeake Bay we have immediate success at 20 plus miles! Our five watt hand-held radios have great difficulty at two miles through the forest but can talk twelve miles across the Chesapeake.