Two Way Radio Communication Training (The Basics)

Two Way Radio Communication Training

by Hunter_Prepper

There are no handheld radios that will ever cover any kind of range (beyond LOS (Line of Sight)) without some kind of special circumstances or a repeater. The laws of physics, solid matter and the curvature of the Earth simply get in the way. So, here are your realistic options for achieving long (er) range.

Amateur Radio (Ham) can offer coverage from a few miles to thousands of miles, depending on the band and equipment used. Portable VHF/UHF (Very High Frequency/Ultra High Frequency) radios will have a range by themselves of a few miles, usually less than 10, but can increase that range dramatically through the use of a repeater. HF (High Frequency) radios with good antennas can offer ranges of hundreds or thousands of miles depending on the band, time of day and atmospheric conditions. Repeater sites can fail and atmospheric conditions can be severely disrupted by solar activity, so depending on this is still a gamble, but it is by far the best option for reliable communications range.

General Mobile Radio Service (GMRS) High-end GMRS radios operate similarly to UHF Ham radio equipment. GMRS users can use up to 50 watts, high-gain antennas and they can even use and own repeater sites. This is not going to happen using the common bubble pack available as a 22 channel pair of radios. You need real radios, such as the Motorola or Vertex variety. Handheld radios are not going to get more than a few miles range without some unusual circumstances or a repeater.

All other radio services are simplex or point-to-point and don’t offer repeaters, therefore limiting the radios range to no further than the horizon. Radio waves do not follow the contour of the terrain, they operate in straight lines, and any object of sufficient size will block them. What this means is, that they will not go through mountains, nor will they go over the mountain and back down the other side. They will not penetrate buildings very well, travel through dense vegetation such as a forest very well or follow the curvature of the Earth. Radio waves of sufficient power and that are below a certain frequency can be reflected off the upper layers of the atmosphere, but this is dependent on things such as time of day and solar activity.

The only reliable way to get communications range more than a few miles is to install antennas on tall masts or towers (you can hang them in trees) and with sufficient power and provided the terrain isn’t too mountainous and in the way, then you can begin to get some reliable and consistent range out of your radio system, but expecting a handheld radio to offer coverage of more than a few miles is asking too much. Hand-held Ham, GMRS and MURS (Multi-Use Radio Service) radios on VHF and UHF frequencies will offer a standalone range of a few miles over average terrain. The FRS (Family Radio Service) bubble pack radios, that you can buy at a Wal-Mart or Academy Sports, for example, can only be expected to be reliable at distances measured in yards rather than miles.

Here a few major things that limit your ability to talk to your buddy. This may be oversimplified, but I hope it will help you start to understand the big picture.

Propagation: This is the pathway of the radio waves you send to your buddy. If they are in LOS (line of sight)–which means you could actually see him if you could see 30miles–then you simply need the right antenna and power level to talk to him.

Most of us don’t have line-of-sight to the people we want to talk to. Usually, trees, buildings, mountains or other barriers block the signal. They turn the “36-mile” radios into the 1-mile radius you have! There are a few ways to combat these problems, and this brings us to the next point.

Antenna design: There are antennas out there designed to “focus” your transmitting or receiving into one direction. Kind of like a flashlight you can point in any direction you choose. They are called “directional” antennas and have design names like “yagi”, “quad” or “log periodic”.  Old analog TV antennas are commonly a yagi or log periodic design–that’s why you rotate them to get the best signal.

Anyway, if you and your buddy point these directional antennas at each other you will stand a better chance of hearing each other. Because they are physically large they almost always used at fixed locations like a home.

Other antennas are designed to broadcast in all directions. They are called “omnidirectional”. Much like a light bulb, they send their energy out in all directions. It’s the type of antenna used by police cars and walkie-talkies. However, they aren’t good for talking over long distance unless you feed them some serious power. But sometimes you can use a radio with a directional antenna pointing at someone with an Omni… and still have a good result.

Antennas do best when they are used at the highest geographical point. It gets you closer to the LOS mentioned earlier; you can better your position by transmitting from the top of a hill, from the highest floor of a building, or from an antenna on top of roof, mast or tower.

One more note. Your antenna needs to be tuned to the frequency you are using. This makes your antenna as efficient as possible. This efficiency is a huge concern–and it brings us to the next topic.  (Tuning your antenna is too much info to put into this article, do your research and learn)

Power: You have to use enough power to create a signal that reaches your buddy. The best antenna in the world won’t work if you don’t feed it enough juice. And the most juice in the world won’t make your antenna work of it’s not tuned.

The general rule of communication is to use only as much power as you need. This is courtesy to others who use the same or nearby frequencies. You don’t want to overpower them. Also, it helps save money on your electric bill!

Summary: To achieve constant and reliable 30-mile range,  You need to use enough power WITH a tuned antenna AT the best height you can manage.

The inexpensive FRS or GMRS radios (like the Motorola Talkabout radios) won’t do it. They put out a maximum 0.5 watts of power (half a watt!) Their antennas are very inefficient.  However, they would be good for communications on your property.

Other public radio frequencies such as MURS band have very limited power output–2 watts.

CB radio can legally put out 4 watts. There’s also a mode feature that allows 12 watts in “single sideband” mode. It’s also referred to as “SSB”. Your voices will sound funny due to the mode, but it is a much more efficient use of your radio’s power. CB antennas tend to be long or very big. It will take some experimenting to find the best antenna position to use.  You will also need to “tune” the antenna for optimal performance.

The only way you’re going to legally talk to your buddy with a relatively compact antenna and good audio quality is to get into Amateur Radio. It will enable you to use higher power (some mobile radios can put out 75 watts), and there are many antenna options for home and mobile use.  I know not everyone wants to register with the Government, but sometimes it has its advantages.  Besides just because you have a license does not mean you have a radio if you understand.  There is also no law against buying the radio “just” to listen.

If you choose amateur radio, you will likely need a mobile car radio that puts out 50 watts or more into a tuned mobile antenna that is not too short. You can use the same radio in your house… with a better performing antenna on the roof, inside the attic, or on an antenna mast.  By having a radio of this type you will be able to have a mobile station and a base station using one radio and two antennas.

There are many, many other more involved options and details such as grounding, repeaters, etc. It is hard to cover everything in a single post, it is best to get a good book; I started with “HAM radio for Dummies” and one from the ARRL (Amateur Radio Relay League). But hopefully, this will help you ask more questions.

Abbreviations and Explanations:

VHF – Very High Frequency; is the ITU-designated range of radio frequency electromagnetic waves from 30 MHz to 300 MHz.  Frequencies immediately below VHF are denoted high frequency (HF), and the next higher frequencies are known as ultra high frequency (UHF).  VHF propagation characteristics are ideal for short-distance terrestrial communication, with a range generally somewhat farther than line-of-sight from the transmitter (see formula below). Unlike high frequencies (HF), the ionosphere does not usually reflect VHF waves (called skywave propagation) so transmissions are restricted to the local radio horizon less than 100 miles. VHF is also less affected by atmospheric noise and interference from electrical equipment than lower frequencies. Whilst it is blocked by land features such as hills and mountains, it is less affected by buildings and other less substantial objects than UHF frequencies.

UHF – Ultra High Frequency; designates the ITU radio frequency range of electromagnetic waves between 300 MHz and 3 GHz (3,000 MHz), also known as the decimeter band or decimeter wave as the wavelengths range from one to ten decimetres; that is 10 centimeters to 1 meter. Radio waves with frequencies above the UHF band fall into the SHF (super-high frequency) or microwave frequency range. Lower frequency signals fall into the VHF (very high frequency) or lower bands. UHF radio waves propagate mainly by line of sight; they are blocked by hills and large buildings although the transmission through building walls is high enough for indoor reception. They are used for television broadcasting, cordless phones, walkie-talkies, satellite communication, and numerous other applications.

I hope this has helped you or at least guided you in making an informed decision on what to purchase and what you can expect for your purchase.

4 Comments

  1. While in the military, I was taught that HF waves, while using a long wire antenna, would create “ground waves” that would follow the curvature of the earth. The limitation was in the power of the transmitter. So, provided you could set up a long wire antenna and output enough power, you should be able to overcome many minor obstacles. It goes without saying that this requires a higher cost.

  2. Don’t forget NVIS. A very simple wire dipole in an inverted “V” or located very close the the ground can provide excellent communications within 0-400 miles. As always when dealing with HF, time of day and solar activity plays a big part. I have a simple G5RV mounted in an inverted “V” and can reliably talk to many hams within 300 miles and often further at night using 80M. Although not ideal, I can also get extended ranges of 1000-1200 miles on 20M during the day and early evening.

  3. Hunter Prepper, Thank you for a “primer” so to speak on radios. I won’t pretend to know anything about radio commo, I used radios (usually FM short-range) in the military but do not really know their complex workings. I have a GMRS set that I use around my property that does ok for what I need it for, and I have a couple of CB radios that I have managed to get some good distances on (one time over 30 miles but that was extraordinary).

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