Hi Guy, > This is a non-issue, Tom.
I think it is a critical issue, because it demonstrates the difference between EM radiation and induction fields that only store and return energy to the system. > It stems from what I meant when I said "cancel fields". > > Apparently some considerable number, even the majority, think this > phrase means cancel fields entirely. To others this means > cancellation is taking place at some level. Then the question arises, how much does it reduce fields? As far as I know, all we can do is redistribute those fields as evenly as possible over the widest area possible in the lossy media to reduce losses. > The FCP radiates at -30 dBi according to NEC4. That's really low for > an antenna element. But, it DOES radiate. But that has little to do with local losses in the soil. > According to NEC4, using area integration of field squared data from > the counterpoises only, excluding the vertical radiator, the FCP only > has 8.2% of the power loss in the dirt as a pair of 1/4 wave raised > radials. What do you think of this example using a lossless half wave dipole antenna over the same soil: Dipole with lossless wire: freespace 100% eff and 72.3 ohm 45 feet 46% eff and 37.6 ohms 10 feet 6% efficiency and 54 ohms Comparing an FCP dipole: Freespace 99.2% eff 0.03 ohms 45 feet 20% eff and 0.04 ohms 10 feet 0.4% 1 ohm Here is my confusion: The theory (correct me if I misunderstood it) is folding the element reduces fields in the earth compared to spread-out elements, and concentrating the field in a small area also reduces earth losses. I understand the article to say reducing the area exposed to fields reduces loss. If that is the case, why is a full-size lossless-conductor dipole's efficiency higher (earth losses lower) than a dipole made from two right angle FCP's? Both have equal soils and both are lossless internally, so all losses are by fields in the earth. What I understood, and always found true, is spreading fields out over a larger cross section of lossy media reduced losses. This is because current and electric field density is less. Why does a 260 ft wide lossless dipole have less earth loss than a lossless compact folded antenna at the same height? What am I missing? 73 Tom _______________________________________________ UR RST IS ... ... ..9 QSB QSB - hw? BK
