It takes experience to pick the design that deals with the specs, including a
HV spec.

That's a commercial issue and beyond the scope of this NG.

Who sells them? "Commercial" indicates that such antennas are in production
and being offered for sale.

A
"...if one tolerates bad manners, they grow worse. I must find the oaf who did
this thing, explain to him his offense, give him a chance to apologise, then
kill him." (R.A. Heinlein, "The Cat Who Walks Through Walls")