I had the single bay Zig-a-Log; I never thought of it as a helical antenna. Where I lived at the time was terrible for UHF reception and no antenna I tried made things any better. I wish I had tried the double-bay Zig. The fun thing about that design is that it's stamped out of sheet metal and is supported by a plastic (vinyl) boom. Like bowtie arrays, I guess the 'spread' array was intended to fight UHF's tendency for 'hot' and 'cold' spots.
Linear Mode
