[TowerTalk] Cubex Mantis II

Chuck Dietz w5prchuck at gmail.com
Sat Mar 11 17:24:22 EST 2017


If anyone reading this is contemplating a quad, but is concerned about it
being damaged by wind, I had a 4 element tri-band quad up on the shore for
years and it made it through a major hurricane with only minor damage that
could be repaired from the tower. I have never had a corner come loose on
the several quads I have had. The awesome performance totally outweighs the
trouble!  I say "Go for it!"

Chuck W5PR

On Sat, Mar 11, 2017 at 4:03 PM Jon Pearl - W4ABC <jonpearl at tampabay.rr.com>
wrote:

> Hi Dan,
>
> I don't have any experience with the Cubex 40m cubical quads but I still
> have (stored away) a 4 element 10m-20m of theirs that I used for many
> years.  I'm a long time quad fan, starting with a 2 element Gotham with
> bamboo arms, then a 2 element Skylane with fiberglass arms, then finally
> the 4 el. Cubex.
>
> The weakest point in the Cubex design is the wire elements where they
> are formed into corners.  They are comprised of tinned #14 cu and pass
> through drilled holes in the fiberglass arms.  Over time, due to wind
> oscillations the fiberglass will slowly abrade the wire causing
> failure.  It does take some time, though.  My fix for this problem was
> to purchase a black air shock, airline kit.  I have the fiberglass arms
> stack on brackets on my wooden fence and the short lengths of air line
> passing through the arms has shown little deterioration from the years
> in the sun.
>
> I cut the air line into lengths long enough to pass through (and then
> some) each of the fiberglass arms (longer at the fat ends and shorter at
> the small ends) with the wire elements passing through them.  If I
> remember correctly, as the fiberglass arms are shipped, the drilled
> holes are just large enough to pass the supplied #14 but not the air
> line so I re-drilled all of the element holes with an 1/8th in. drill
> bit.  From that point on, I never realized another broken element again.
>
> There are a lot of written words out there by a lot of different authors
> on quads vs. Yagis.  Anecdotally, I know that as a kid getting ready to
> head out the door for high school each morning, I'd always get up early
> to check 10 and 15 and was amazed to often hear that I was one of the
> first east coast stations to be heard across the pond.  Cycles 20 and 21
> were pretty good to me but so was the quad.
>
> I'll close by mentioning that quads are three dimensional antennas.
> I've always been lucky to have all of them mounted on crank-up and
> tilt-over towers.  When something broke, I could aim the boom end where
> the repairs needed to be made towards the ground and then fold the tower
> over.  On a stick tower like the AN Wireless, if a wire element breaks
> on one of your highest corners (40m), you're not only going to be
> dropping the antenna down beside the tower, but it's going to have to
> remain in a boom-horizontal fashion while you attempt to reach the upper
> corner of your 40m box.
>
> Then again... you may well own a crane!
>
>
>
> 73, Dan,
>
>
>
> Jon Pearl - W4ABC
>
> www.w4abc.com
>
> On 3/10/2017 9:52 AM, Daniel Hileman wrote:
> > Hi Everyone,
> >
> >
> > I am thinking about putting a Cubex Mantis II Quad (2 elements on 40m, 4
> elements 20-10m) on my AN Wireless tower at about 72'.  I am looking to see
> if anyone has experience with this quad, or other 40m quads, and can tell
> me how they like it. Looking for real life performance on 40m Vs a 2 or 3
> element yagi? I know there is quite the debate on this, but not looking for
> "opinions" with no operational experience between the two. This would be
> quite an undertaking to install and looking for whether those with 40m
> quads would do it again, and if they thought the performance was
> better/worse/same as a 2 -3 element yagi.
> >
> >
> > Thanks and 73,
> >
> > Dan N9WX
> > _______________________________________________
> >
>
>
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