I have run my Kiwi here with AM filter for more than a year now almost 24/7 and I am very happy with it. I am only using an old ground mounted Cushcraft R7. I am still planning to expand with additional kiwis for the low bands and a vertical log periodic towards middle EU. In the meantime I like to try a LNA ( with a 50 ohm HP on let say 10 Mhz) on the vertical.
I guess I could cobble together a Norton amp or similar and the HP filter, but before doing so, what are the "big gun" WD kiwi stations out there using if they need a boost??