Hello, fellow 'Talkians --
Some of the most interesting (and fun) TowerTalk posts have been the
'real life adventures' of some TowerTalkians relating to a current
tower/antenna project that resulted in the joy of a successful job (and
occasionally 'the agony of defeat'). Please pass along these progress reports.
We're heading into the busy tower building season of September and October and
I'm sure we'd all like to hear about and to see what's going up. Photos on
your web site are always fun. Let us know.
Relative to this topic, I just spent an interesting week in the San
Francisco Bay Area doing some antenna work and I thought I'd pass along some
of the high points.
I installed my first Cushcraft X-9 at Bruce, W6OPS's lovely home in Napa
- the home of LOTS of grape vines. And filled bottles too.
My first impression is that this is the most mechanically robust
Cushcraft I've ever seen. It uses the same new hardware that the X-7 and new
'hardened' XM240 (they don't even list the 402CD in their catalog - RIP?). The
boom is 2.5 inch and the boom-to-element bracket is a nice extrusion. The
boom-to-mast clamp is innovative in that it features a 'cradle' arrangement.
That means that you can lay the antenna in the cradle while you're installing
the rest of the hardware. My only criticism is that it takes so many nuts and
bolts to secure it. There are almost 2 dozen fasteners in that bracket and I
had to loosen and re-tighten many of them 3 times before everything was
fastened together.
It was hard for me to believe, but they're still using hose clamps on the
elements instead of rivets. Their comment was that "that's the way we've
always done it" but the owner can put some self-tapping sheet metal screws in
the elements if they want. Other antenna manufacturers have gone to rivets
since using rivets decreases the parts cost and makes the antenna lighter
without apparently compromising element strength.
When we first got it on the tower, the SWR readings on my MFJ-259 were
worse than they were on the ground (!). After a quick call to the factory (we
got ahold of Paul, NW1U, right away), he suggested that we check the element
lengths on the driven elements. Since it uses a log cell feed like the TH11 -
actually the whole antenna is like the TH11 - you don't adjust the driven
element lengths. Checking them would have involved lowering the antenna again
so we decided to check the antenna SWR at the rig and voila!, everything was
peachy keen. We were apparently suffering from 'nearby RF overload' on the
analyzer so everything looked FB.
Bruce is a new TowerTalkian so perhaps he'll give us a report on the
performance of the X-9 as he gets some experience with it. BTW, Cushcraft
claims to have shipped 200 of them so far.
More adventures in part 2.
Cheers, Steve K7LXC
http://www.championradio.com
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