CL schrieb:

I'm not saying I "disagree" - though I've never fully gotten into the design
basics/performance, but "I" didn't "design" them - I only sell them!

Bad enough that you believe in the sheet (=****) of the manufacturer. A
professional seller you should know the technical basics on the products
he sells.
Never(!) believe in the "specs" a manufacturer gives, without some
verification of plausibility on it. Name these "broadband groundplane"
antennas JUNK and send them back to the manufacturer. Or keep them on
1/20 of the price and sell them as 'groundplane with gain some*where*
between 25 and 1300Mhz' at 1/10 of the original price. This should
satisfy everybody but the manufacturer :-)

regards,
Volker