Today I modified my 500kHz antenna introducing a spiral inductance/ top capacity hat consisting of around around 8 "spiralling in" turns in the space occupied by the original 28MHz halo. Seeing my initial reports from M0BMU I am some 5-6dB stronger than I was before, I guess because more of the antenna current is in the 6m long vertical section.
Three new 500kHz reports overnight: F4DTL, PA0AM and G4CAO. The improved antenna efficiency is definitely helping. Also my strongest report yet from GM4SLV.