Thanks to everyone who responded .The posts by K7TJR and W8JI were most helpful in understanding what is going on .I should add that the phasing box in the shack is continuously variable, (NCC-1) so changes in the phasing caused by changes in the antenna surroundings came be compensated . It works quite well but I think there maybe some benefit to change the elements to top loaded style.
73 Glenn WW4B _________________ Topband Reflector
