|U.S. RS-1 Clandestine Radio|
From the early SSTR-1, several suitcase radios, the famous Cold War RS-1, village radios for the locals in Vietnam to Burst Coders, it's all there, with images, background information and quite a few schematics. But the articles go beyond the purely technical aspects and tell us about the men and the training, surveillance and bugging, and the encryption of radio messages. You can read about SIGINT and how to counter their colleagues from the other side. There's also a section on British, Russian and German radio sets.
If you're interested in radio transmitters and receivers, and how they were developed and used, you're in for a few hours of good reading. You can find the article in Spy Radio section of militaryradio.com.