The B&W, which comes in several configuations, is a pretty standard
military antenna. We had several of them on various buildings at Ft.
Meade, where I worked and I've seen them on military posts all over.
Several other commands at Ft. Meade also had them. I've also seen then
at some local reserve armories as I drive by them.

With an antenna tuner (usually automatic) they can cover the whole HF
spectrum.

As it is a government issue, it likely can be made by several vendors
to government specs and then bid upon, unless there is something so
unique about it that it is a sole source contract. Some of them I
inventoried when doing site inventories ( I was a US Dept. of Defense
program manager) were, in fact sold to the gov't by B&W which I
believe is short for Barker & Williamson who made ham transmitters in
the 1950's when I was both a kid and first licensed.

I'm not an antenna engineer by any means but someone who was said that
essentially is was a sort of hybrid between a Zepp and a folded
dipole. The extra spacing contributed to its bandwidth. He said the
center had some sort of insulator with a balun transformer. It was
not the most effecient antenna, but could be erected quickly and was
packaged with a mast kit for field operations.
The military version also had the option of stainless steel wire.
Most of the ones I saw were permanently installed.

I was always curious about them, but all my projects were receive-only
for intercept so I never got to play with them at all.

Like to hear more about them.

Jon W3JT