Understanding 2 Way Radios (Walkie Talkies)
Listening is Legal, Transmitting is regulated
In the United States it is legal to listen to (receive) any radio signal (except for cellular and scrambled frequencies). It is talking (transmitting) that is regulated and may necessitate a license.
There is a finite number of radio frequencies, so radio frequencies like other natural resources have to be shared. Laws regulate who and how these frequencies may be used. The available frequencies are divided into "bands" aka "services", and these services are given various names such as: broadcast television, broadcast AM and FM radio, military, police, fire, school buses, air traffic control, wifi, GPS, cell phones, baby monitors, bluetooth, radio controlled cars, etc. Each of these services have their own set of rules that govern how they may be used. The right to transmit on some services is based on a purchase in the free market system, an example of this is FM radio, or cellular phones. The right to transmit on other services is based on ownership of an FCC compliant device, an example of this is a baby monitor. The right to transmit on other services is based on use, an example of this is marine radio. By regulating transmission rights in this way people and businesses are able to share the resource. Without such an agreement radio waves would cause great interfere with each other and render all radios inoperable. By having different sets of rules for each service, the advantages and disadvantages of various systems are balanced. If all frequencies were regulated on the free market system like FM radio, the cost to use baby monitor frequencies would be too costly. The reason there is no cost or license needed to operate a baby monitor is because the devices themselves are regulated to have have very limited range, and owners must accept any interference caused by a neighboring baby monitor. If marine radios were manufactured like baby monitors they wouldn't have the range needed to communicate with other vessels. Marine radios are therefor manufactured to transmit long distance, but their use is restricted by purpose; only people operating a boat are allowed to use them. There are VERY hefty fines for manufacturing or using radios not in compliance with FCC law. The services available to civilians for 2-way radio, walkie-talkie like communication are: CB, FRS, GMRS, MURS, and Amateur Radio. Each of these services have their own set of rules, of which we will discuss here.
Some radio waves naturally travel just a few miles, while others can travel all the way around the world with little power. To help boost propagation and the distance a radio wave travels, people apply more electrical power and/or use better antennas, but this only does so much. A frequency's wavelength (and the weather on the sun) also have a lot to do with how far a radio signals will travel. Getting a radio signal to travel a long distance isn't always the goal, in fact often times it is good to try to reduce the distance a radio signal will travel in order to limit interference with other signals. If the listener is nearby it makes no sense to crowd the airways with a signal that will travel around the world. If all radio waves traveled around the world there would be a great deal of interference. Sharing the airways with other services is essential, so it is essential that most radio signal transmissions be limited.
License Free Community Radio
The walkie talkies found at a sporting good store, Wal-Mart, or Target are sometimes called blister pack radios because of their packaging. These rules regulating these radios are called Family Radio Service (FRS). FRS radios and Citizen Band (CB) radios do not require a fee or license to transmit. The distance these radios will work are by design limited to one to five miles (although some manufactures will claim more). The government restricts the wattage and antennas of these so they do not create interference with other users. CB radios are restricted to no more than 4 watts, and FRS blister pack radios shall not transmit using more than 2 watts. These restriction limit the distance these radios can cover, thereby reducing interference with other users and allowing more people to use them.
There is another community radio service called General Mobile Radio Service (GMRS). Many blister pack radios are actually combination FRS/GMRS radios. Some of the channels are governed by FRS rules, and some are governed by GMRS rules. What most people don't realize is that to legally use the GMRS channels you have to have a license. There is no test to get a GMRS license; you simply pay a $70 fee. Pay the fee, and you can legally transmit on GMRS. The license is good for 10 years. The GMRS channels are slightly better than the FRS channels because they are 5 watts instead of 2 watts. Unlike CB and FRS, GMRS also allows larger antennas and repeaters. GMRS repeaters may use up to 50 watts. By using a repeater and/or a larger antenna you can boost your range to about 30 miles or so, but unless you use these additional features GMRS isn't much better than FRS.
Transmitting on Amateur Radio Service frequencies (aka Ham Radio) requires a license, but the pay off is well worth it because what you get for your effort is increased skill, far more frequencies (channels), no antenna restrictions (better signal), up to 1,500 watts, and distances of up to thousands of miles! It used to be that in order to get an Amateur Radio license you had to learn Morse Code, but lucky for you this requirement has been eliminated. You don't need to be an electrical engineer to get your amateur radio license. Getting an amateur radio license is much like getting a driver's license in that anyone who wants one and is willing to put in a little effort can get one can.
There are three levels of Amateur Radio licenses: Technician, General, and Extra. The Technician class is not only the easiest of the three licenses to get, for most people it is the only one you will really ever need. The technician class license gives you access to transmit on the frequencies (channels) you need the most. It only costs $15 to take the Technician class exam and get your license. When you pass the Technician test you will have an option to take the General class exam immediately for FREE, and if you pass the General you have the option to take the Extra class exam immidately for FREE. Each subsequent test is roughly twice as hard as the one prior. Although you could try to pass more than one exam to save having to pay the $15 fee at a later date, there really isn't much of a need. The General class license is nice because it gives you access to use some cool frequencies, but the cost of the radios to use those frequencies is quite high. The Extra class license gives you access to a few more frequencies, but it is more of a novelty and gives you bragging rights more than anything else.
An Amateur Radio license is good for 10 years, and when those 10 years are up renewing it is free and easy.
Channels Vs. Frequency
CB, FRS, and GMRS are channelized radio services; Amateur Radio is not. Understanding what is meant by this, and the difference betweem channels and frequencies is helpful. An FRS radio has 22 channels, and the frequency stored into memory as channel 1 is frequently 462.5625 Mhz. Channels 1-22 are each a memmory location, and the manufacturer has stored an electromagnetic frequency into each of these memory locations. Most people don't know what the frequency is, they only care about the channel number. FRS radios are not all programmed the same, so what is channel 1 on one radio may be Channel 9 on another, making interoperability between different manufacturers and models difficult. If we knew the frequencies, we would have the information needed for full interoperability between radios, and with Amateur Radio that is exactly what we have.
A radio signal is defined not by its channel number but by its frequency, which is the measurment of how many times the signal cycles in a second. The unit of measurement is called hertz. One hertz equals one cycle per second; radio waves range from thousands (kilohertz / Khz) to millions (megahertz / MHz) to billions (gigahertz / Ghz) of cycles per second. Using my Amateur radio, I talk to some frineds each week on 145.430 Mhz. Since I use this frequency a lot I stored this frequency into my radio's memory as Channel 1. My friend's have undoubtedly stored the 145.430 Mhz frequency into their radios using different channels. The channel number is irrelevant, it is the frequency that matters! The radios Amateur Radio operators use give us full control over the radio, so amoung other things, we are able to store frequencies in whatever channel we desire.
In addition to the 22 FRS channels, GMRS gives users access to 16 additional channels, both of which are located at about 460 MHz. CB gives users access to 40 channels located at about 27 MHz. Unlike CB, FRS, and GMRS community radio services that have defined channel numbers and frequencies. In Amateur Radio individual end users get to decide how to divide, use, and assign frequencies to channels, thereby creating an art and giving users more freedom of use than what is entrusted to the general population with community radio services. For this reason it is challenging to give an exact number of channels available to Ham Radio Operators, but for the sake of comparison, it is safe to say that Amateur Radio gives users access to hundreds if not thousands of channels.