Rag Chewers' Club (RCC). www.spar-hams.org
Radio Society of Great Britain (RSGB).www.rsgb.org.uk
International Amateur Radio Union (IARU). www.iaru.orgr
International Amateur Radio Union (IARU). www.iaru.orgr
Tropospheric Ducting Forecast. www.dxinfocentre.com/tropo_nwe.html
Spaceweather. http://spaceweather.com/
Spaceweather. www.solarham.com/
QTH Locator Finder. http://f6fvy.free.fr/qthLocator/fullScreen.php
Great Circle Map. http://ns6t.net/azimuth/azimuth.html