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Re: [TowerTalk] Rohn BX bolts, plates and shelves...

To: towertalk@contesting.com
Subject: Re: [TowerTalk] Rohn BX bolts, plates and shelves...
From: Kim Elmore <cw_de_n5op@sbcglobal.net>
Date: Tue, 14 Jun 2016 11:27:17 -0500
List-post: <towertalk@contesting.com">mailto:towertalk@contesting.com>
I concur: I've had an HDBX48 since 1986 and have had ~13 sq ft on it most of 
that time. You will have to strengthen the rotor plate -- it's stamped steel 
with tabs that bolt to the inside of each led. Those tabs will break without 
more support. 

They are stout towers but quite uncomfortable to climb. 

Kim N5OP

"People that make music together cannot be enemies, at least as long as the 
music lasts." -- Paul Hindemith

> On Jun 14, 2016, at 09:30, TexasRF--- via TowerTalk 
> <towertalk@contesting.com> wrote:
> 
> Kirk, these towers are now made by Thomas Shelby Co. You can find them  
> with a Google search.
> 
> When you delete the two top sections the tower becomes a model HDBX48 and  
> the wind loading is 18 sq ft. They always said the maximum boom length 
> should be  limited to 10 ft but most users ignored that directive.
> 
> The section #3 top plate is called a BXT3, rotor plate BXR3. The stock top  
> plate is drilled for a plumbing floor flange. Many users simply screwed a 
> short  water pipe nipple into the flange and used it as a top sleeve for the 
> mast. If  you want an inexpensive bearing, a Yaesu GS065 is only $65 and can 
> be mounted on  the BXT3 plate.
> 
> Bolts, most likely the existing bolts are fine but that is your call.
> 
> Foundation hole size for an HDBX48 is specified at 5' 9" square, 4ft deep.  
> It takes 4.9 cu yds. There is a hinged base, BXHC78, with 3/4" anchor rods  
> and a fixed base, BXB8 made with 4ft stubs available. Some users have made 
> their  own base stubs from galvanized plumbing pipe. A 10ft length of the 
> 1.9" OD size  cut into three pieces and drilled for the legs bolts would be a 
> good  choice.
> 
> These were great towers for the money back when Rohn was making them. I  
> have not seen one of the Shelby models and I see the pricing is much higher 
> now,  naturally.
> 
> Whatever you do, don't plan on re-galvanizing the sections as the rivets  
> will melt and you will have a giant erector set on your hands. 
> 
> Hope you find some use for this info.
> 
> 73,
> Gerald Williamson K5GW
> GM Texas Towers
> 
> 
> 
> 
> 
> In a message dated 6/14/2016 4:22:27 A.M. Central Daylight Time,  
> towertalk@contesting.com writes:
> 
> Hi,  gang,
> I will soon be installing a Rohn BX64 in my back yard. To beef up the  end 
> result, I plan to install only 6 of the 8 sections, leaving me with what  is 
> hopefully a much beefier 48-foot tower. According to what I've read, the  
> full 64-footer is only rated for 6 sq feet of antenna at 70 MPH (with a  
> 10-foot boom). I live in an 80-MPH max zone, and although I've never seen a  
> Rohn lattice tower fail with only a TV antenna on it in these parts, I'd like 
>  
> a little more margin and a little more antenna. Minus the two top sections,  
> the wind load seems to be upwards of 20 square feet (way more than the 8-12 
> I  need), and I'm guessing that a 12-foot boom would also work. The tower 
> will  hold up one leg of a wire horizontal loop and will host a rotator and a 
> smaller beam (a Tennadyne T-6, a Spiderbeam, a 2-el quad, a hexbeam, a  
> friend's mothballed Mosley Classic 33, or a multiband rotatable dipole -- 
> only 
> one at a time!) VHF antennas will be on a different tower.
> 
> I have a few  questions (naturally :)
> 1. I will need to purchase or fabricate a top plate  and a rotator shelf 
> for what I think is "section 3" (top two sections of the  BX64 are not 
> installed). I was planning to fabricate a triangular plate with  three bent 
> "mounting tabs" that I can bolt to the three corrugated legs of the  now-top 
> section (two bolt holes exist at the top of each leg). I was planning  to use 
> 3/16 
> steel plate (or something similar), but I'm open to suggestion. I  think 
> Rohn makes such a plate, but I'm not sure what it's called or what it  costs 
> (budget isn't extreme). Suggestions?
> 2. I'm looking to add some kind  of a thrust bearing to this top plate to 
> save wear and tear on my rotator (a  rebuilt Ham xxx, Yaesu 450 / 800, etc). 
> I'm hoping to use "farm store / farm  equipment parts," and don't want to 
> spend a billion dollars on Rohn's bearing.  (Not looking to install massive 
> antennas...just want a solid, trouble-free  installation cuz it's cold in MN 
> and tower climbing is sometimes  impossible.)
> 3. I'm considering buying new bolts for the tower, and I've  read up on the 
> dangers of using SS hardware, hardware of unknown parentage,  etc. I'm okay 
> using Rohn "shouldered" bolts, but so far the least expensive  package I've 
> found is about $150. It sucks when the bolt kit costs as much as  the 
> entire tower...! Most of the existing bolts are in good shape, but some  were 
> horrendously tight, and when we took the tower down we had to use a huge  
> breaker bar to remove some of the large-size bolts. I'm not especially keen 
> on  
> reusing those... Any secret sources for reasonably priced BX bolt kits?
> 4.  I haven't looked at the catalog specs in a long while, but I installed 
> many  BX48s back in the late '70s. I think a lot of installers back then 
> (perhaps  today, too) dug holes that were too small. Still, none I've ever 
> seen 
> fell  over, except when matched against a tornado. I was planning to dig a 
> 4 x 4  hole 5 feet deep, lined with golf-ball size rock for drainage and 
> probably  with a minimal rebar cage and Rohn stubs. My soil type is very 
> sandy, 
> but  well-packed (new to me). I haven't checked with the utility company 
> yet to see  if they have a psi rating for the soil in my part of town. The 
> two 
> companies  that install TV towers in this area don't do anything 
> differently regardless  of soil types (naturally!). And I think their holes 
> are too 
> small, anyway...  Thoughts?
> Thanks, gang, I appreciate your input,
> --Kirk, NT0Z My  book, "Stealth Amateur Radio," is now available from 
> www.stealthamateur.com  and on the Amazon Kindle  (soon)
> _______________________________________________
> 
> 
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