Many thanks to everybody who responded to my inquiry. I received over twenty responses, with many excellent suggestions. Turns out most folks homebrew their own connectors, using brass plumbing fittings, and I received a number of innovative designs. The aluminum jacketed 1/2 inch 50 ohm hardline (RG-331/U) is rather unusual these days (a decade or so ago, large quantites were surplused by the CATV industry), and off-the-shelf connectors are hard to find at a reasonable price. Connectors are readily available for Heliax and Superflex, but unfortunately these don't work with the cable.
I think 50 ohm aluminum hardline is excellent for long runs without a lot of bends. It's very stiff but also very tough. The vinyl jacket that covers the shield is 1/16in thick (total diameter 5/8"), and the aluminum tube is virtually varmit proof. My version of the cable has a solid copper inner conductor, .161" diameter, so losses are very low. I have a 500 ft run from my 160m vertical to the junction panel at my tower, and another 200 ft of heliax to my station. The antenna and radial field has been under construction throughout the summer, and this afternoon some friends are coming by to help me erect the 26m Spiderpole. With luck, I should be on the air with it this weekend. Thanks again to everybody for your help and suggestions. 73, Jim W8ZR _________________ Topband Reflector