When guys in our club start to talk about A-indexes and K-indexes, I normally say that I don’t use either of those to predict propagation. When they’d ask what I do use, I reply, “I use the E-index.”
“What’s the E-index?” they ask.
“Well,” I joke, “E stands for ‘ear’ and if I can hear stations on a band then I figure that propagation is pretty good. If I don’t hear any stations, then it’s probably bad.” That usually get a chuckle out of them.
I may be changing my tune, however. This week, I covered propagation in the General Class license course. To cover it properly, I had to bone up on the topic myself. In the course of doing so, I found the topic to be much more interesting and useful than I would have thought, and there are quite a few resources on the Web that makes it easy to learn.
Here are a few websites to explore:
- Collection of Propagation Information. As the name implies, this site collects data related to propagation and displays it on a single page. Included are various measurements of the solar flux index, A- and K-indexes, sunspot numbers and a grey line map.
- Near-Real-Time MUF Map. This map, updated approximately every five minutes, shows Maximum Usable Frequencies (MUFs) for 3,000 kilometer radio signal paths. It also shows auroral ovals and the sunrise/sunset terminator (gray line). The map is produced by PropLab, a program you can purchase on this website for $150.
- KN4LF’s Radio Propagation Theory Notes. KN4LF is a space weather scientist with the U.S. government.
- International Beacon Project. The NCDXF, in cooperation with the IARU, constructed and operates a worldwide network of high-frequency radio beacons on 14.100, 18.110, 21.150, 24.930, and 28.200 MHz. These beacons help both amateur and commercial high-frequency radio users assess the current condition of the ionosphere.
- DX Atlas. this company produces the software DXatlas, Ionoprobe, and HamCap to help hams predict propagation conditions. While not free, you can download the programs and use them for free for 30 days.
I really don’t need yet another thing to learn and work at, but knowing about this stuff will certainly make you a better amateur radio operator. I think it will be worth the effort.
Update 5/27/05: In the May 4, 2005 edition of the Contest Rate Sheet, Ward N0AX writes:
The details of short wave propagation are available in a detailed tutorial Introduction to HF Radio Propagation available at no charge from the Australian Space Weather Agency at http://www.ips.gov.au.
I just looked it over quickly, but the sections I read were very well written. I’ll not only be recommending this to my General Class students, but studying it myself as well.
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