[Antennaware] 3 element sideways vees - coax lengths?
K1to at aol.com
K1to at aol.com
Tue Nov 17 19:48:34 PST 2009
- 3 inverted vee elements, standard #14 or #12 insulated wire fed in the
- Ground the unused 2 elements. A friend advises that especially here in
FL that "floating" the unused elements will allow them to build up a charge,
thus attracting lightning, so I should ground them instead.
- Mount on an 87' tower that also has 5 HF Yagis on it. Guys are broken
up with insulators. The downside of this is that the tower is a few feet
short for allowing the vees to have the ideal included angle of 90 deg.
- Use RG8X Mini for the feedlines to the switch box, along with the K3LR
method of beads over a 14" section of thin coax at each feedpoint.
I downloaded the demo version of EZNEC last night and enjoyed learning it
tremendously. Wow, Roy -- what a full-functioned app! Anyway, the
learning curve for entering the wires was not bad at all and I soon had the 3 vees
in their sideways positions around the center, all fed in the middle.
But as soon as I got to the Holy Grail problem of how long to make the
feedlines, I hit my roadblock and don't know how to proceed.
Here's what I've found published to date:
- K3LR/WA3FET/K3LC design uses 4 sideways vees, floats the unused ones
(does that matter?), and uses 153.45 degrees of feedline on each element.
Their ELNEC design was quite precise and thorough. Circa 1992. Full article
in Antenna Compendium Vol 4. See p.11 in particular.
- K1WA 5L half-wave sloper array uses 135 deg of feedline and opens the
unused lines. This design goes back to the '70s and was published in many
ARRL Antenna Books.
- W7LR built a 4L 40 array and also concluded that using 135 deg was
correct. See Feb 1995 QST - Tech Correspondence.
Side note - RG8X VF is listed as 0.75 and 0.78 in various places. This is
trivial, since it just gives a starting place from which to trim more
I'm grateful for any input and assistance on this and hope it's a
worthwhile pursuit vs. just separating the flys*** from the pepper!
73, Dan, K1TO
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