DX TIPS for Begginners written by Carl Mann
[tab name=”About Carl Mann”]
Carl Mann has been listening to short-wave since 1956. He began after noticing the distant stations audible between the locals on the AM band. This started his armchair travels that most DXers embark upon to the four corners of the world. Thousands of loggings, tapings, and hundreds of QSL’s later, this accumulated experience is briefly summarized in “DX TIPS FOR BEGINNERS” to speed along newcomers in their enjoyment of the short-wave bands. A native of the state of Nebraska, Carl’s real travels have included much of the western U.S. while pursuing a career in broadcasting, plus a visit to Korea and Japan during a hitch in the U.S. Army in the Vietnam era. As a broadcaster, Carl has been a technician, news director, rock DJ on a clear channel station in Oklahoma City, and program director for AM and FM stations in Cedar Rapids, Iowa, and Omaha, Nebraska. During the army years, he was an announcer for the American Forces Korea Network outlet near the DMZ. He’s also credited as writer/producer for several weekend specials for syndication to radio, including SEVENTIES REWIND and a RICK NELSON special. Carl still chases the DX and plans trips to new places with his wife, Sharie, as time permits. A member of various short-wave and medium wave radio clubs, Carl has been contributor to the clubs and co-hosted three club conventions. He was an official monitor for two years for Radio Nederland and Radio RSA. Maps, pennants, and pins on his office walls attest to his SWL past. Carl brings 30 years of experience to the DX TIPS series, with the hope it brings the same enjoyment to new listeners today as it has for him and his friends through the years.
[tab name=”Basics of DXing”]
You are probably familiar enough with the radio dial to know where the medium wave AM band is located. Short-wave is an extension upward of that band where radio signals take on a property to travel great distances. Let’s look more closely and see why short-wave radio can reach out like it does, and just what bands, and megahertz are. First, a band is any group of continuous frequencies. The signposts to tell us where we are on the bands is the frequency itself, measured in megahertz, or the metrically smaller kilohertz. To simplify, frequency is the number of radio waves per second that leave the station’s antenna. If there are a thousand waves per second radiating from the antenna, the frequency is one thousand Hertz, or a kilohertz. When you get up to one million waves per second, that’s a thousand kilohertz, also called a megahertz.
The same frequency can also be given as a wavelength in meters. This is not widely done anymore like it was in the early days of radio, but identifying the meter bands is still commonplace. To picture the relationship between frequency and wavelength, visualize the radio waves, the electrical fields traveling outward from the station antenna. The number of waves radiated per second is the frequency, and the distance between each wave leaving the antenna, measured in meters, is the wavelength. So, as the frequency gets higher, the wavelengths become shorter. You will notice that the meter bands are measured in smaller numbers as the frequency becomes higher. To illustrate, the 5mHz region is in the 60 meter band, and the 9.5 mHz area is in the 31 meter band. To help understand short-wave reception, you must understand the basic ways radio signals travel, called propagation. Propagation changes as you tune from one end of the band to the other. The short-wave band extends from 1.6 mHz to 30 mHz. Starting at the low end, a radio signal will travel along the ground for much longer distances, over a hundred miles. Also lower frequency signals are more likely to suffer from atmospheric storms and static. The static lessens as you tune higher, but more importantly, the ground waves of these higher frequency stations become smaller. In place of a large ground wave, the radiated power from the station becomes increasingly stronger in an upward path, and that becomes a sky wave. It’s this sky wave on higher frequency stations that can travel such long distances. They go upward, reflect off the ionosphere high above the earth, and land back on earth a thousand miles away. This is called a skip signal. And it’s why these higher short-wave frequencies can reach around the world. But there is an upper limit past which these higher frequencies no longer bounce off the ionosphere. After reaching a certain high frequency, which can vary from day to day, the sky wave penetrates the ionosphere, and travels on into space instead of reflecting back to earth. That’s why higher frequency broadcasts from FM, Television, and two-way communications don’t go around the world like short-wave does.