[TowerTalk] B&W folded dipoles

[Jim Lux]

I'm looking for some details on the dimensions and design of the Barker and 
Williamson "folded dipoles", for the purposes of building an accurate NEC 
model.

 From some casual web searching (on TT, among other places), it looks like 
these things are basically a folded dipole with a resistor in the middle of 
the fold.

I'm looking for things like detailed dimensions (how far apart are the two 
wires?)
What's in the "coax to antenna transition"?  Is it a balun? Or, is it just 
two wires?
What's in the "magic box" at the top of the antenna (a resistor? a tuning 
network?)... the photo on the B&W website shows a metal strap between the 
magic box and the coax, but it's not clear if that's an actual electrical 
connection (if so, to what)

I'd also be interested in any measured performance data (who knows.. the 
gov't uses them, maybe someone actually tested one on an antenna range 
somewhere?)

Thanks, all...

Jim, W6RMK