Short Wave Communications

High Frequency radio can be a valuable tool in an emergency.

April 10, 2020 By R.W. Parker

“HF” or High Frequency radio (aka short wave) has historically proven to be an extremely survivable communications platform. It can be used to communicate around the block, or around the world. Unlike the internet, it cannot be switched off at the whim of some tyrant. The equipment used cannot be damaged by some anonymous, pimply-faced hacker. Best of all, a two-way short wave station can be set up rather easily, using economical equipment and a simple antenna made from copper wire. Such a station will support SSB radiotelephony (voice comms, known simply as “fone”), or myriad digital modes with the addition of ancillary equipment. Why such capabilities might come in handy, I will leave to the imagination of the reader.

Few subjects are as vast as radio. Even when we concentrate on one area of the spectrum, the topic is still almost measureless. However, this article will provide the reader with enough information to procure the necessary equipment and set up an efficient HF communications station. All that’s required are three basic pieces of gear, so let’s take a look at each one.

1. THE TRANSCEIVER

To begin, you’ll need to select an HF transceiver (so named because it transmits and receives). Like other electronic equipment, modern Amateur Radio transceivers range from relatively simple and economical, to those which are amazingly complex and astronomical in price. But since point-to-point comms are essentially “the need to know and the need to tell”, all a transceiver really needs to do is transmit and receive. Beyond the circuits required to properly accomplish those functions, added frills on a transceiver increase cost and often compromise simplicity of operation.

Units typifying the “no frills” breed of transceiver are the Yaesu FT-450D, Icom IC-718 or Alinco DX-SR8T. The Icom IC-7200 and Yaesu FT-897D are also fairly straightforward, and have a rugged “mil-spec” appearance. Additionally, the Yaesu FT897D can also be used with self-contained batteries as a field radio (albeit at QRP, or reduced output power). All of these radios come standard with a hand held microphone. Catalogs from the major suppliers of Amateur Radio equipment are free for the asking, and will give you a good idea of the plethora of equipment that’s available.

Because of their broadband design, today’s transceivers also incorporate a “general coverage” Communications Receiver, meaning that they can receive frequencies well below the “AM” (or medium wave) broadcast band through the upper end of the HF spectrum, continuously and without gaps. This definitely isn’t a “frill”, but a genuine bonus. It means that when you buy a modern transceiver, you’re also getting an excellent short wave receiver in the bargain. And listening can often be every bit as essential as transmitting.

THE “MARS” MODIFICATION

Many modern amateur transceivers can be easily modified (often by the owner) so that they will also transmit on all frequencies between 1.8 and 30 Megahertz (MHz), instead of just being able to transmit on the amateur bands only. This is often referred to as the MARS modification. Amateurs who participate in the Military Affiliate Radio System require equipment that is capable of operating outside of the bands allocated for amateur use, and some dealers might be able to perform the “MARS Mod” on your transceiver at the time of purchase. If you’re an Amateur Radio operator who’s interested in joining MARS, information can be found on the internet.

Other operation on those “outband” frequencies might require special licensing or be unlawful in the here-and-now, but the capability for such operation could be a real bonus after The Big Shutdown.

2. THE POWER SUPPLY

The transceivers I’ve mentioned all operate from a power source that provides 13.8 VDC at about 25 amps. In a field-portable situation (or when the power goes out), they can run from your vehicle’s electrical system. But in normal fixed station use, they will require a regulated power supply. You may use a supply offered by the manufacturer as a matching accessory, or a generic one provided that it meets the above requirements. Comparison shopping here can save you some money, but don’t skimp. A power supply employing a transformer will cost more than the switching type, but any supply intended for amateur radio use and rated for 25-30 amps should be fine.

3. THE ANTENNA

Your transceiver won’t work without an antenna, and the quality of your antenna is going to affect your ability to transmit and receive information more than anything else. Hundreds of volumes have been written about the construction of HF antennas, and there are countless styles. Store-bought antennas can range from wire types costing a few bucks, to fancy tower-mounted arrays that require a second mortgage. The selection can be confusing, but fear not! I have “worked” (made contact with) thousands of stations in every state and on every continent, and I’ve never used anything more than a standard 100-watt transceiver and antennas that I’ve fashioned from copper wire. And you can, too!

Antennas come in two basic flavors: “monoband” (for one specific range of frequencies) and “multi-band”. And since they’re frequency specific, antennas get bigger as the frequency decreases. But you needn’t concern yourself with too much antenna theory at this point. Nowadays, a “plug ‘n play” method exists for getting an efficient multi-band antenna on the air, and that’s the microprocessor controlled automatic antenna tuner.

An automatic antenna tuner is mounted out in the yard, and it turns a length of plain old copper wire into a pretty respectable antenna. Most solid state transceivers are equipped with circuitry that sends frequency information and a bit of RF (radio frequency) energy to the tuner with the press of a button. The tuner then “matches” the wire antenna to your frequency in the matter of a few seconds, and you’re ready to talk!

When purchasing your automatic antenna tuner, make sure it is the type that tunes a random wire, not a “coax-fed” antenna. Some transceiver manufacturers make both types. For the Icom transceivers mentioned, you’d want the Icom AH-4 tuner, while the Yaesu FT-450D and FT-897D use the Yaesu FC-40. The aftermarket “Smartuners” made by SGC are economical and reliable units, offering better frequency coverage than some OEM tuners. Their SG-237 model is an excellent choice for transceivers in the 100-watt class, and it covers 1.8 to 60 MHz.

Once you’ve mounted the automatic tuner outdoors (about 15-20 feet away from your transceiver), connect the designated terminal to a good ground. An 8-foot ground rod and clamp, driven into the ground near the tuner is usually sufficient. These can be purchased from your local electrical supply or home center. Then, you simply connect a length of wire to the “antenna” terminal on the tuner, and attach the far end of the wire to a “dogbone” insulator. Tie a support rope to the other end of the insulator, and haul the antenna up into a tall tree. Instructions regarding wire lengths and configurations are included with the tuner.

There are various methods for getting a support rope over a tall tree limb. I attached a cheap fishing reel to a wrist slingshot, and similar ready made gizmos can be purchased. After shooting a lead sinker over my chosen limb, I remove the sinker and tie my support rope to the fishing line (para cord makes a good support rope). Reeling in the fishing line pulls up my support rope and antenna. The end of the support rope is then tied off on a low branch.

When properly set up, a random wire antenna can give excellent results. For the past 15 years, one of my best performing antennas has been a length of plain old #14 insulated copper wire that’s about 160 feet long. Roughly 125 feet of the wire is suspended horizontally between two trees, at a height of about 35 feet. The remaining 35 feet runs vertically downward, where it connects to my auto tuner. It looks like an inverted “L”, and that’s exactly what this type of wire antenna is called. And with that simple wire and 100 watts of power I have worked all 50 states and over 100 countries, often besting the signals of those running much fancier equipment!

4. PUTTING IT ALL TOGETHER

You will also want to provide a good ground for your transceiver. Again, an 8-foot ground rod should suffice. Ground connections to both antenna tuner and transceiver should be as short and direct as possible, so site your operating position at the ingress point for antenna and ground leads. Use heavy copper wire for connecting to the ground terminals provided. Deviating from good grounding practice is NOT permissible, for safety as well as performance. DON’T connect your gear to the cover plate screw on a wall outlet with a piece of zip cord, DON’T run 25-foot “ground” wires from a second story window, etc. All sorts of problems can result from improper grounding.

Connect your transceiver to the power supply, and plug the supply into a 120VAC outlet. Run the control cable and coaxial cable from the tuner back to the transceiver, and connect them. Plug in your microphone, adjust your transceiver per the supplied instructions, and you’re on the air!

DO I NEED A LICENSE?

As long as the government is functioning and has enforcement capability, the answer is yes. To operate in the amateur bands, you must possess a valid Amateur Radio Station license. Even though you might have 1^st Amendment objections (as do I) to government licensing of what is essentially an “electronic printing press”, there are two good reasons for obtaining an amateur license.

First, if you possess a valid license, you cannot be busted for “unlicensed operation”. Operation without an “instrument of authorization” can lead not only to stiff fines, but confiscation of your equipment.

Second, there is no better way to learn about something than actual participation, and HF radio communication is no exception. Once you have your license, you can freely communicate with other amateurs and really start learning. Long distance HF radio communication (“DX”) is possible because radio waves reflect from different layers in the ionosphere and back to the earth, skipping hundreds and even thousands of miles. By “working” other amateur radio stations, you will soon learn which frequencies are best for establishing contact with different areas of the globe, depending on the time of day or season.

But don’t throw in the towel because you’ll be required to pass an examination in order to receive an Amateur Radio Station license. Since there is no longer a requirement to learn Morse code, you can obtain your license in no time at all by using the “quick ‘n dirty” method. You won’t have to spend one dime on study materials, nor will you even have to study!

The tests for a station license are multiple choice, and a passing grade can be obtained through simple rote memorization. If you have access to the internet, you’ve got it made. All you have to do is visit a site that offers free online practice exams (like QRZ.com), and take the tests that are required to obtain a General Class amateur license. The last exam element (for the amateur Extra Class license) will entitle you to greater operating privileges, but it is not at all necessary.

Start taking the tests for an hour or so every day. At the end of each practice test, your score will be displayed. A person with no knowledge of radio whatsoever might score 10% at first, but after a week or two your scores should improve to at least 90%. When you are consistently scoring in the nineties, visit arrl.org to find a local Amateur Radio club that is giving the actual exam. The questions used in the online practice tests are taken verbatim from the pool of actual exam questions -- you will be answering the same questions that you’ve become so intimately familiar with. Simply show up with your pencil and the required fee, and you’ll ace the tests!

Some prima donnas insist that obtaining a license in this manner is sacrilege, but I say “bunk!”

There are amateurs who’ve obtained their station license by memorizing the test answers, and became truly outstanding operators. Conversely, there are those who’ve held an Extra Class license for 30 years, and behave like total imbeciles on the air. So, don’t be an imbecile – be outstanding! Spend time listening to good operators, strive to emulate them, and try to learn something about radio.

“OUTBAND” OPERATION

From a legal standpoint, operation outside of the bands allocated for amateur use can be a bit dicey if you’re not licensed to be there. However, certain scenarios might one day arise where “going off the reservation” might provide a tactical edge. In such a situation, it would certainly attract less attention to use a frequency that’s allocated for a maritime coastal station in Shanghai, than one used by the Air Force for communicating with Strategic Air Command bombers. A current copy of the Klingenfuss Guide to Utility Radio Stations, or the Klingenfuss Super Frequency List on CD will let you know who uses that frequency before you tune your antenna and key your transmitter. These references can be purchased from Universal Radio, and that’s all I’m gonna say on this subject!