On 10/1/2020 10:53 PM, [email protected] wrote:
The engineer who lead development, testing and evaluation of the array explained that the ground mats served two purposes: - almost completely suppressed signals received by the sloping ends of the Beverages by making them into efficient transmission lines with very low spurious signal leakage compared to a sloping wires over poorly conducting soil or vertical wires at each end of a Beverage. W3LPL
I don't buy the engineer's reasoning here. If we use superposition into vertical and horizontal electric fields, it seems to be apparent that the ground mat would do nothing to prevent the last 50 feet from acting like a sloping vertical with respect to vertically polarized waves. If anything, it would make the vertical work better, as verticals always do when radials are added. I could believe that the mat would prevent the last 50 feet from acting like a Beverage, but that "solves" what is a non-problem. I think everyone including the engineer agrees that 4 vertical feet is 4 vertical feet no matter how many horizontal feet are added. Because of superposition. I am thinking that a very simple test of this would be to do an A/B test of the pattern with only the last sloping 50 feet connected, comparing with and without the mat. I'm surprised that the engineer didn't do this as confirmation. Is there any article that establishes that the 4 foot vertical drop at the end of the Beverage is actually significant to the overall performance of the Beverage? I've never seen such an article myself. It is hard to imagine that only 4 feet of conductor would pick up much signal. Rick N6RK _________________ Searchable Archives: http://www.contesting.com/_topband - Topband Reflector
