[TowerTalk] K0XG Orbital Rotor on US Tower HDX589

[Jim Thomson]

Date: Thu, 13 Oct 2011 11:17:11 -0400 (EDT)
From: K7LXC at aol.com
Subject: Re: [TowerTalk] K0XG Orbital Rotor on US Tower HDX589
 
In a message dated 10/12/2011 8:33:14 P.M. Pacific Daylight Time,  
towertalk-request at contesting.com writes:

>  Anyone out there with this configuration or mounted one  of these 
Orbital rotors (K0XG) on a crank-up before? I would like to exchange  ideas as 
this is my plan.


    Where are you proposing to mount it?   I'd  say the only place you could 
mount it feasibly is on the bottom section.  Any other place and the added 
weight of this brute side mount will exceed the  capacity of the tower 
immediately even with no antenna on it. .  


 
    If you proceed with this plan, be sure to keep  your homeowner's 
insurance paid up because you're going to need it.
 
Cheers,
Steve     K7LXC

##  I see no weight listed for the K0XG unit.   The Tic ring [ 1032] will easily 
fit  at either the 38' level or the 72' level  on my HDX-689. 

## My old style HDX-689 uses 5/16"  cable  + a 4:1 mech advantage. That equates
to 44 k lbs breaking.  Even at 20%  of breaking, that's still  8800 lbs....and that has to take the
weight of the upper  4 x sections only...+ mast/ants, etc.   The upper 4 x sections  + mast/ants
are no where near 8800 lbs, do don't sweat it. 


## ok, the next  3 x sections  above the base one, all have  THREE  1/4"   lifting cables, PER section. 
IE:  one cable per each of the 3 x tower section faces.   This  provides for a more even pull.  There
is no way ur gonna break all 3 x cables  on those sections.   In order for thise sections to come crashing down,
all 3 x cables on that section have to break. 

##  The very top section on my HDX-689  only has ONE  1/4" lift cable on it..[no mech advantage].  
 Now, I wouldn't stuff huge weight on the very top section.... but you are not anyway ! 
  1/4" cable is good for 7000 lbs.   20% of that = 1400 lbs.  
The very top section + mast/ants is way less than 1400 lbs.   The ring rotor/orbital rotor would be installed at the
72' level, or the  55'  level.   At both the 72' and 55'  level, those sections have 3 x lift cables on em.   IE:  3 x 7000=
21,000  lb breaking.   Even at  20%  of  21,000 lb = 4200lbs..and you are still no where near that. 

##  You can easily  put a ring rotor at the 55' / 72' level on the  89'  crank ups.   Any wind load is at the 55' /72'  level  X
55'/72'  = bending moment  at the base of the tower. 

##  BTW...UST makes a small hand crank device, that  slips over the 14"  pulley spokes.   It's  used IF you get a commercial AC power failure. 
It's easy to turn that 14"  pulley by hand. A cordless drill  will also work.    IE: if the WX forecast is  for 100 mph wind at midnight, then
simply get the tower cranked down asap.  Worst case is the AC power goes out...and tower is at max height....and a huge windstorm is on 
it's way in < 1  hr.  Once the tower is down..who cares  abt the WX ?  

##  Both my tic  1032's  weigh aprx 121 lbs.  I'm guessing the orbital K0XG 's  weigh 200-350 lbs.   

later........ Jim  VE7RF