GP antennas are easy to make at home, but are unefficient. Even a dipole is better.
However, they are small, and we have them on our site, too, 2 versions.
They are however robust, easy to disassemble and assemble and have their advantages.
One of the two models on our site is wideband and requires no tuning, that would be the one
with extremely thick radiator.
https://www.pcs-electronics.com/shop/an ... 108-1000w/
3/4 wave Exterminator / Predators are basically J-poles, we have predators in our store that can handle
as much as 3KW. 1KW version is also available.
https://www.pcs-electronics.com/shop/an ... tor-steel/
Actually, if you don't mind having a directional antenna sending most of the power in one
direction, these look just like a tv antenna and nobody will figure it out.
https://www.pcs-electronics.com/shop/an ... antenna-2/
The selected direction would have really great range (probably about 2x more) while the rest would of course have less than with an omnidirectional antenna. That's where the gain comes from.
Hope this helps
