I want to build a dual discone one upside down for 928+ & one the right way up for 918+ , the discone i saw and was told about equalises the frequency , cross phase something something, what you get is a discone that operates at 923 give or take a few mhz due to stratospheric conditions. Which are beyond my current comprehension. You lose penetration below the horizon (for some complicated jargon) and gain sensitivity just below peak. When Rolley returns from Bali i will ask him to explain it in a clear and comprehensible manner.
It has to be mounted 6-8mtrs above ground.