Topband: "Nested" 160/80m Arrays? Real World Experiences?
Jon Zaimes AA1K
jz73 at verizon.net
Mon Jan 31 11:16:44 EST 2005
>ON4UN's book mentions "nested" arrays, as in a 80m 4x array
>located inside a 160m 4x array ... anyone on here done this?
I tried this with my series-fed 100-ft tower for 160. I had visions of nesting parastic arrays for 40, 80 and 160.
To start, I used a 1/4 wave wire for 80 meters and a 1/4 wire for 40 meters hung off opposite sides of the tower, spaced out a foot or two. Each was fed with a separate feedline and against the large radial field under the vertical.
It worked fine on 40 meters.
It worked poorly on 80 meters and I finally abandoned it for other antennas on that band. There was obviously some interaction with the 160-meter tower when trying to use the 80-meter vertical.
Last week while doing some other work on the tower I decided to remove the 80 meter element. I then rechecked the 160-meter resonant point with my MFJ269 analyzer and found it had dropped below the band! I then removed a short linear-loading section I had previously used to resonate the tower and then it was resonant on 1830 again. So there obviously was some interaction with the 80 meter wire element.
This might work OK if each element was left "floating" while using it on the other bands.
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