This is a one valve [tube] radio that believe it or not I constructed 48 years ago. It remained lost but was discovered again during a recent house move. The valve used is a battery R.F. pentode dating from around 1948 on a B7G base. The type number is DF91 or the American equivalent, the 1T4....

Yup, there's even a video of THIS! Amazing, soon we'll see people opening up utility bills on youtube. Anyway, if you've always used RG-8 or RG-213, this is a nice step right past LMR-400 and into the real stuff. This is the last step before Heliax. The difference w/ 600 Vs the first...