Date: Wed, 28 Apr 2010 08:22:32 -0500
From: "Jim McDonald" <jim@n7us.net>
Subject: [TowerTalk] US Tower damaged by lightning
My US Tower HDX-589MDPL, which is motorized with the remote control option,
recently took a very large, direct lightning hit.
## My HDX-689 is sitting in the driveway... delivered last Monday. Although
it
came with the remote control box, the previous owner had main control box
on tower wired, so the up/down can only be done from the tower. I believe the
remote box in shack is an option, offered by UST ? Mine has a short 120 vac
waterproof
cable.. with 120 vac plug.. that went into a 20A [10ga] outside waterproof
circuit.
## The idea here was to unplug the power.. at the tower, when not raising /
lowering.
The up/down switch on the tower has a spring loaded center off. The
optional box in shack
does NOT have a spring loaded center off. IMO... I don't like the idea of
raising/lowering
these towers from the shack... too easy for coax to get snagged going up...or
down...
esp in any kind of windstorm.
## as an aside. I notice that all my coax arms don't line up [the far ends]
. ..esp the
one at the 21' level.
My question concerns the US Tower repairs. US Tower says the cable and all
pulleys need to be replaced and the tower inspected - all necessary to
ensure structural integrity. The cables look to me to be undamaged, and the
pulleys seemed to turn, as I didn't have any difficulty lowering the tower
with a US Tower emergency hand crank. BTW, anyone with a motorized tower
should consider getting the emergency hand crank in case the tower has to be
lowered when the power if off.
### Check out the pdf from that cable forensic place. A real eye opener.
internal strands change geometry, when they hit just 300 deg C. You can have
outer layer of strands looking good [strands u can see],.. and have a total
mess inside
per their pix.
## I bought, and just received the emergency crank handle for the 689 tower.
I still can't figure out where it goes, mine came with 3 x bolts..every 120
deg. There is
nothing on the 689, that it can mate too..anywhere on the drive assy... is
there a trick to this?
Jim,
Sorry my shop manager just got back to me what we can do you can purchase a
crank
handle assembly. Crank handle will turn the pulley on the input shaft attached
to the
gear box, the UST part number is 15003-0015-0000.
Obviously the relay box has to be replaced. US Tower's price to travel from
Kansas to the Chicago area and do the work is unreasonably high, in my
opinion, and they haven't given me a technical explanation on why the cables
and pulley need to be replaced to "ensure structural integrity." They said
that the inspection could be performed by another AWS-certified welder, but
I don't know of any locals with cable or pulley replacement experience.
## That entire UST control box should be simple to replace, with a
new one. [swap out] . Steve, VE6WZ, figured out how to change
out both pulley's and also the cables, on his own 589 tower.
## On my 689, the winch cable is 5/16".. uses 4 x pulleys.. and has
a 4: 1 mech advantage. All upper cables are 1/4"... use only ONE pulley,
and offer no mech advantage. All upper cables are aprx 42' long, with
nicropress crimp on each end. Pulleys are solid AL. All the upper cables
look fairly straightforward to replace.
## what lube goes on these cables ? One poster said to use LPS-3...
if near salt water. Other's use Pre-lube 9. UST sez to use nothing,as
it will attract dirt/debris. I thought the pre-lube stuff penetrated to inner
strands ? I have LPS 1+2. I'm sure LPS-3 was like thicker goop, used for
chains, etc. Also... what about the pair of parallel chains on the UST tower?
Mine has parallel chains, parallel sprockets... between winch drum... and gear
redux box. If those things break, the whole tower comes down. That's
something
else you may want to check.
## I noticed something else. It's supposed to retract to 23' 8'. Mine is
sitting at
26' 1". And the limit switch appears to be right at the end of it's mounting
slot. I'd like
the nested height to be lower, it looks like to pull that off, the slot needs
to be milled
out a tiny bit ?
later......... Jim VE7RF
It's a safe assumption that my wife isn't enthused about ham antennas these
days.
Thanks for any information!
Jim N7US
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