Investigated this little jewell yesterday. Made up some techncial notes and took pics. Schematic included. Nice grid modulated AM TX set covering 2 to 4.5MHz.
A 1613 is used as a modulator. I do not find curves for it as a class A amp. Is it equivalent to something else, like a 6F6?
Has anyone tun one of these, or has an interest in this kind of thing? Not much on the WWW. It's a treasure trove of parts, but I don't want to part it. The front/exterior is not corroded yet very paintless and dirty, but inside - nice and clean.http://www.bunkerofdoom.com/mil/bc653a/index.html