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

[TexasRF at aol.com]

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 at 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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