Mark Dittmar's site: Hartley's, Regens, and an MOPA.
http://www.qsl.net/ab0cw/
An excellent few pages describing an early style TNT (Tuned-Not-Tuned) transmitter:
http://www.io.com/~nielw/tnt/tnt.htm
Electric Radio Magazine's site.
http://www.ermag.com
