[TowerTalk] Which Quad?

[Gregg Corsello]

Saad,

I have been playing around with Lightning Bolt quads since 1994.

The first was a 4-el, 5-bander on a 32' x 3" x .0625 boom, using ALL
Lightning Bolt spreaders, with the balun and ONE common feedline.  The
boom WAS trussed.  It came apart May 19, 1997(it had been up 3 years) in
a 80+ mph microburst.  The boom tore like a tin can from the center
sleeve and many of the spreaders fractured.

I rebuilt it as a 6-el, 5-band quad on a 32' x 3" x .0625 boom (Alcoa
6061-T6).  This time the spacing was shortened to 8', PLUS an additional
driven element for 10 and 12 meters was added 4' in front of the
reflector.  The balun was eliminated in favor of a remote coax switch
and separate feedlines for each driven element.  The antenna performed
much better this way.  This antenna had 16 spreaders from Lightning Bolt
Co. and 8 spreaders from Max-Gain Systems.  Again, the boom WAS
trussed.  This antenna came apart much like the first one (in 85+ mph
winds on June 30, 1998).  The boom tore in almost the same location as
the first one, right next to the center sleeve.  ONE Lightning Bolt
spreader survived (out of 16) and ALL EIGHT Max-Gain Systems spreaders
survived.

My reaction?

-If building a long-boom quad, use at least a 3" O.D. boom, TRUSSED,
with a wall thickness of at least .125" (you may wish to consider .250",
but it will be heavy).
-Separate feedlines with a remote coax switch seem to work better than
one common feedline (with one common feedline, the antenna seems to
exhibit back-to-front on 10 meters rather than front-to-back).
-The data regarding the fiberglass spreaders seems to speak for itself.
Max-Gain Systems has a very good product, the wall-thickness of the
fiberglass seems to be about twice that of Lightning Bolt's (more
weight), and the price is about identical (about $20/spreader shipped to
your door).
-Think about using a 3" O.D. boom even for a 2-element quad on a 8'
boom.

73, de Gregg, K3QK

pictures of my quads at:

http://www.qsl.net/k3qk



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