In the modern world, there are few things as critical as the propagation of information. Anytime, day or night, we have access to news, weather, and interpersonal communications. When that information is
unavailable whether due to a misplaced cell phone, internet disruption, or other factor, we begin to panic, feeling cut off and isolated.
When disaster strikes, up to date information could be as vital to your survival as food, shelter, or a means to defend yourself.
We can all make plans for our retreat and relocation, but without a means of contacting one another when the time comes, all we can do is wait and hope that everyone is on their way.
What is amateur radio?
Amateur radio, also known as ham radio, is a service designed for the purpose of intercommunication between individuals whether for casual chatting, emergency preparation, or in the event of an actual emergency. The FCC permits citizens that have proven proficiency in FCC rule and of reasonable technical ability to use this service. To do so, one must pass a written exam and register their information with the FCC to obtain a license. Transmitting on amateur radio bands without a license could subject a person to fines or even imprisonment. However, there is one caveat to this rule. During an emergency, when lives are at risk, anything goes.
The phrase “anything goes” rarely has as much significance as it does in a TEOTWAWKI situation. Now, I am certainly not condoning the unlicensed use of amateur radio. But there may come a time that the only thing between you and rescue is a ham transceiver.
As quoted in the FCC amateur radio rule book:
§97.405 Station in distress.
(a) No provision of these rules prevents the use by an amateur station in distress of any means at its disposal to attract attention, make known its condition and location, and obtain assistance.
(b) No provision of these rules prevents the use by a station, in the exceptional circumstances described in paragraph (a), of any means of radio communications at its disposal to assist a station in distress.
Note: With that said, I would still encourage anyone making any effort in preparation to seriously consider following the licensing procedure.
Amateur radio signals are capable of traveling thousands of miles, or as short as tens of miles.
There are many factors that will affect the distance your signal will travel.
Some of them include:
- Transmit Frequency
Just like with an AM/FM radio, there is a wide spread of radio frequencies that signals can be received on. Common allocations for amateur radio can be found anywhere from 3M MegaHertz (MHz) to well over 440MHz.
Typically the lower frequencies, from 3-30MHz (High Frequency or HF) provide the greatest distance with the least amount of power. This is accomplished by natural phenomena called ‘propagation’, which will be explained later.
VHF 30-300MHz (Very High Frequency) and UHF 300-3000MHz (Ultra High Frequency) offer a very high quality signal for ‘line of site’ distances up to about 50 miles. Police, fire, and private services rely on these frequencies due to the clarity and reliability of communications. FRS/GMRS (Family Radio Service) radios use 460MHz (UHF).
- Antenna
In amateur radio, the most important factor is the antenna. An antenna can be as simple as a long piece of wire strung through a tree, or as large as an array of directional antennas hundreds of feet in the air. Just because it’s simple though, doesn’t mean it won’t work. I have talked to a ham in Portugal from my living room in Illinois using nothing more than a piece of wire looped around my ceiling fan.
‘Any’ antenna will work better than ‘no antenna’.
- Transmit Power
Transmit power is measured in watts. While amateur radio has a limit of 1,500 Watts, most transceivers will only put out about 50-100 watts. Ideally, the more watts put out, the farther the signal will travel. You must also remember though, the more watts transmitted, the more power the radio consumes. This is something to keep in mind when battery power is in precious demand.
It is generally a good practice to keep output power low when possible, and make up the difference with improvements in your antenna. I have talked to Japan on 5 watts from Illinois. Power isn’t everything.
- Propagation
During the day, solar rays charge different layers of the atmosphere which create a reflective barrier for radio waves. As the sun fades for the day, so does our propagation.
Higher frequencies require a higher amount of charged particles. Radio waves that do not bounce are simply absorbed or pass right through. During times of good propagation, it is possible to send very weak signals across the globe.
We can, to an extent, control how far our signal will go by utilizing the three main types of propagation.
- Skywave (long skip)
By utilizing an antenna that has a low take off angle, like a vertical antenna or high dipole (like your FM stereo comes with), our signals are directed at the horizon which will hit the atmosphere and bounce back to earth. (The earth is round, remember?)
- NVIS (Near Vertical Incidence Skywave)
With a lower dipole antenna or tilted vertical antenna, we increase the angle of the radio waves. Therefore, the waves go up sharply and bounce down much closer.
- Groundwave (line of sight)
Line of sight communications solely rely on the receiving station being within a straight line of the sending station. A walkie-talkie is a good example of this. Repeaters, which I will cover below, are often used to increase range of line of site radio equipment. Output power and antenna height greatly improve line-of-sight (LOS) communication.
Setting up a station
When determining what radio equipment will suit your needs, you must first decide on a few things.
- How far do I need to communicate?
- How portable will I need it to be?
- How much can I spend?
VHF/UHF
If you answered the first question with “less than 50 miles”, then you can easily set yourself up with a useable system for under $200. VHF and UHF transceivers are often called 2 meter and 70 centimeter radios, respectively. 2M and 70CM refer to the length of the actual radio wave. 2M operates around 145MHz and 70CM operates around 440MHz.
Handhelds
A handheld unit has the advantage of small size, internal battery pack, and built in antenna. On the other hand, the small size, internal battery pack, and built in antenna is a serious compromise regarding transmit and receive distance. Typical handhelds maximum power output is about 5 watts and the internal battery won’t last long at that power level. The functionality of a handheld unit relies on repeaters. Without a repeater, a handheld would be limited to about 10 miles or less.
A repeater is a transceiver with a very high antenna that receives a signal on one frequency, and retransmits on another, usually at a much higher power. Through the use of repeaters, it is possible to work stations >100 miles away with a walkie-talkie. This may sound like fine business, but repeaters are privately owned and would likely be locked down by the owners, without power, or seized by the government, should society crumble.
Mobiles
Mobile units are designed to be mounted in a vehicle and are powered by 12 volts. Although an external antenna is required, this gives the user the flexibility to decide which antenna works best for them. Most mobile units can produce at least 50 watts and can be reduced to lower power as needed. A base or even portable station can be easily setup using a mobile radio, rechargeable 12 VDC battery, and an antenna placed as high as possible. With careful planning and experimenting, this system can be optimized to reach distances of 50 miles or more, creating an efficient point-to-point communication link.
HF
For nationwide communication, HF is going to be the winner hands down. HF radios are typically capable of more than 100 watts and under good conditions can talk coast to coast and across the ocean. The greater distance is attributed to propagation, as described earlier.
The biggest stumbling block with HF radios is the cost. With a starting price of around $700, most folks will find it very hard to make room in their budget for this.
Another consideration is the antenna. To work efficiently, an antenna should be at least ¼ wavelength long. Depending on the frequency, this could be anywhere between 10’ to well over 60’. But as stated before, any antenna is better than no antenna.
Conclusion
Undoubtedly, whether your plans are staying or relocating, reliable communications will be a must for you and your group. This article is written as a primer into amateur radio and to simplify what can seem to be an overwhelming step of preparedness. There are hundreds of volumes written on the subject, and I would encourage anyone serious about prepping to research further.
I really can’t stress enough that you should take the time now to get licensed and work out any problems before they occur.
Links:
www.arrl.org Find testing locations and just about anything else ham-related.
www.qrz.com Take online practice tests for amateur radio exams