User talk:Mikeag

Talk to most people about how far a VHF signal (above 30 Mhz) will travel, and most times, the answer will be 'line of sight'. However, as there sometimes is in nature, there's exceptions to the rule. Many phenomenon can cause a VHF signal to travel hundreds of miles or more. Events such as a stalled weather front to a meteor shower or even the solar wind can change things in the atmosphere and make a signal travel much further than normal.

Hams (and folks involved in TV/FM DXing) have been studying this for years. Many of these phenomenon have been cataloged, but not are all well understood. If you are interested in a description of how a VHF signal (or above) can travel, take a look at this article on the WikiPedia site. Keep in mind that FM and TV broadcast, as well as ham frequencies, are found above 30 mhz - so openings in one service can, and often does, suggest openings across an entire band, regardless of service.

The links below are not intended to be comprehensive, but rather be a starting point for getting more information. Additional links with descriptions and maps are always welcome.

The RR forum for discussing VHF/UHF skip can be found here

Maps

• William Hepburn's Worldwide Tropospheric Ducting Forecasts
• V-UHF QSO Real Time Maps
• VHF Propagation Maps

Technical Articles

• Sporadic-E propagation at VHF
• M1BWR's Non-Ducting Tropo Inner Sanctum
• The Northern Lights and 6 Meters
• The DX Robot Automatic real-time AURORA and E-skip warnings via email or mobile phone
• KG0VL VHF Aurora Radio Research
• WA5IYX VHF Propagation Info

Worldwide TV/FM DX Association links

• Worldwide TV/FM DX Association home (new)
• WTFDA Propagation Page old but still lots of useful information
• WTFDA links page (new site)