A Simple, Short Introduction to Space Weather and DXing
One of my many interests is the hobby of receiving long distance radio signals. This is known as "DXing", DX being short for "distance". Most DXing is done on shortwave, frequencies being between 1.6MHz & 30MHz. Signals on shortwave can travel great distances but reception is not always reliable.
How well signals can be heard is dependant on several factors, such as the receiving equipment in use, the antenna, also space weather plays an important part. Shortwave signals are bounced back from the ionesphere and the weather up there is as changeable as it is locally! If you want to learn more about radio propagation, a thorough, although complicated guide, can be found here.
There are many different types of radio signals broadcast including amateur radio transmissions; aircraft communications, CB, and many more! The majority of signals are from "broadcast stations", such as the BBC World Service, Voice of Russia, Radio Netherlands etc. Programmes are typically informative with some music.
Below is a short extract from Radio St Helena. They only make one special broadcast each year. This extract was recorded by myself on 15-12-2007 at 20.15utc (8.15pm) on a frequency 11.092.5MHz in upper sideband. The receiver was a Win Radio G313i, and the antenna being a longwire of some 22 metres terminating with a Wellbrook balun.
DXing can also be done on higher frequencies and my main interest is currently to hear distant stations on the domestic FM band (87.5-108MHz). How these signals travel for extended distances is quite different from how shortwave signals travel. The three main ways that such signals here in Britain are via Sporadic E; Tropospheric Propagation and Meteor Scatter. If you are interested then this guide written by William Kitching is a good place for "getting started".
TV stations can also travel unusually long distances, and an excellent guide can be read here. I don't think I need to add anything more!
Space Weather:
Solar X-rays:
Geomagnetic Field: |
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From n3kl.org
Here are a few links:
(updated 08-24-2008)