For the past 13 years John G8MNY has been producing technical bulletins for distribution by Packet Radio, now the collection of articles is available on the web.
The articles cover a wide range of subjects including Antennas, ATV, Broadcast, Modifications, Power Amplifiers and Portable and Mobile operation.
If you want to know how to make a Slim Jim antenna, a battery charger or a 12V Cow Fence for /P operation there's an article in the archive.
The extensive collection can be downloaded from http://www.theskywaves.net/technical.html
Caterham Radio Group - http://www.theskywaves.net/