|Do the following:
a. Sketch a diagram showing how radio waves travel locally and around the world. Explain how the broadcast radio stations WWV and WWVH can be used to help determine what you will hear when you listen to a shortwave radio.
b. Explain the difference between a DX and a local station. Discuss what the Federal Communications Commission (FCC) does and how it is different from the International Telecommunications Union.
The most common way for radio waves to travel is in a straight line of sight from one antenna to another. This is most common for radio waves using frequencies of 30 MegaHertz (30 MHz or 30 million changes of direction per second) or higher.
Radio sky waves between 3 and 30 MHz can also reflect off the electrically charged upper atmosphere, which is called the Ionosphere, to then bounce thousands of miles around the earth.
Radio Waves below 3 Mhz can hug the earth’s surface to travel hundreds of miles using ground waves.
WWV and WWVH
Radio station WWV is located in Fort Collins Colorado and WWVH is located in Hawaii. Both provide precise time signals and transmit exactly on the frequencies of 5, 10, 15 and 25 MHz. They also provide infomation on how well the Ionosphere is bouncing radio signals today.
They can be used to set your clock, to calibrate your receiver and transmitter, and to see how well radio signals can travel to and from Colorado and Hawaii.
Local vs DX – Signals from nearby stations are called local, while those from far away places are called “DX”. “DX” is the old Morse Code abbreviation for “distance”.
The FCC is the Federal Communications Commission. It regulates and issues radio licenses in the United States. The ITU is the International Telecommunications Union and the agency of the United Nations that establishes international standards for radio.