Date: Fri, 23 Dec 2011 17:17:38 -0800
From: "Rich Hallman - N7TR" <rich@n7tr.com>
Subject: Re: [TowerTalk] US Tower HDX-589HD? Now 689
Just re-measured the tower....
37in on the bottom and 18 in top section. Looks to be an HDX-689. The
base plate was not a standard T-Plate either...but a large full plate
with 4 bolt holes per leg.
Explains why I had such a problem getting it off the truck with my
tractor when my other 589 came off no problem.
Re-cabling the tower, then up it goes when the weather is warmer with a
M2 4 El 40 Meter beam.
Thanks...
## That is a HDX-689. I have one as well. BTW, that base plate is a whopping
560 lbs.
## They made 2 x versions of the 689. Mine is the original, and uses 'Z'
bracing from top
to bottom of all 5 x sections. On the bottom 4-5' of each section...and also
the top 4-5' of each section,
it's also an 'X'. The bottom 7' of each section on mine has a tube slid into
it, and welded into place,
so the wall thickness is massive. The new version of a 689 weighs 3250 lbs.
The truck driver put his
scale on mine, when unloading, and it was dead on 5000 lbs !
## either way, you have the... 'real deal'. They rate the 689 at 75 sq ft @ 50
mph...and 50 sq ft @ 70 mph.
My base plate takes 1.125" anchor rods. I bought 12 x 60" long anchor rods
from Portland bolt. [105 ksi
variety, they are colour coded..and red = 105 ksi]. I had then cut 6"
threads on each end of all 12 x rods.
To increase the up lift capacity, I had the local metal shop cut 3 x plates.
Each plate is 9" square x 3/8" thick.
each plate has 4 x 1.25" holes punched into it, with [ i think] 5.25" C to C
spacing]. I used the heavy duty
nuts,[slightly bigger] and hardened flat washers. The 3 x plates, of course,
are embedded deep into the
concrete. The crane lifted that 560lb base plate 6' above the lawn, while i
got up on a sawhorse..and
cranked the nuts on with the impact wrench. [ the 24 x nuts for the 3 x
plates were installed the day b4]
The entire mess [ base plate + 12 x anchor rods + 3 x plates] was lowered into
the hole..and resting on
2 x 10' long x rectangular tubes. rect tubes are 6" wide x 2" tall [ 1/4"
wall thickness]. The rect tubes
are wrapped in plastic and taped beforehand. The perimeter of the hole was
lined with 4x4's...and
leveled beforehand.
## Of course, the cage was installed 2 x weeks before. After we were satisfied
the base plate was where we wanted it,
crane slings were removed. A few days later, the 2 x cement trucks showed
up,+ a line pump. A month later
the base plate is elevated easily, via cranking on just one nut per corner.
Then the 2 x rectangular tubes are slid out.
Base plate is then leveled, with digital levels. I have loads of pix of all
this if you want them.
later...... Jim VE7RF
_______________________________________________
_______________________________________________
TowerTalk mailing list
TowerTalk@contesting.com
http://lists.contesting.com/mailman/listinfo/towertalk
|