early radio timeline http://www.netsonian.com/antiqueradio/timeline/a.htm
amateur radio timeline 1820-1937 http://www.vistech.net/users/w1fji/timeline.html
preservation and education of information age technologies http://www.infoage.org/
radio history on the web http://www.oldradio.com/
american early radio history http://earlyradiohistory.us/
shortwave history links http://www181.pair.com/otsw/net.html
shortwave links page and softwares http://www.blackcatsystems.com/radio/shortwave.html
HF propagation resource center and space weather forecasts http://hfradio.org/latest_chart.html
shortwave airtime rental http://www.airtime.be/
The Early History of Radio: From Faraday to Marconi (I E E History of Technology Series)
by G. R. M. Garratt, G.R.M. Garratt
A History of Telegraphy: Its History and Technology
by Ken Beauchamp, K. G. Beauchamp
Inventing American Broadcasting 1899-1922 (Johns Hopkins Studies in the History of Technology)
by Susan J. Douglas
Wireless: From Marconi's Black-Box to the Audion (Transformations: Studies in the History of Science and Technology)
by Sungook Hong
History of Telecommunications Technology
by Christopher H. Sterling
Shortwave Listening Guidebook: The Complete Guide to Hearing the World
by Harry L. Helms