In general, any metal in the near field of the array will have an effect on pattern. This includes radials under the array. It's hard to predict what the results will be in a particular situation, but it can be modeled in EZNEC or other modeling programs. I've done this in the past and the results for particular situations range from negligible effects to significant pattern distortion. This is also true for any other receiving array system. Such antennas are sensitive to metallic objects nearby, and this needs to be taken into account in laying out an array.
My RX array is installed over the outer part of the radial field for my 160m transmit vertical system. Modeling predicted little effect and in practice I can't say I see any degradation in RX array performance. I also have a switching arrangement that detunes the transmit vertical while I'm receiving on the RX array. This arrangement is described in the user's manual. 73, John W1FV -----Original Message----- From: Topband [mailto:[email protected]] On Behalf Of Ron Feutz Sent: Monday, December 07, 2015 10:58 PM To: [email protected] Subject: Re: Topband: 9 circle array The site I have available for one of these systems is part of the former radial field for my now-defunct 160M 4-square. The RX array would go where the ground has radials from the former elements. These radial wires are buried under years of accumulated tree stuff and it would not be practical to remove them. The radials are not physically connected to the radial fields of the one or two transmit elements I will be using. How would the old radial wires affect performance, if at all? Ron KK9K _________________ Topband Reflector Archives - http://www.contesting.com/_topband
