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)
> _______________________________________________
>
>
>
> _______________________________________________
> TowerTalk mailing list
> TowerTalk@contesting.com
> http://lists.contesting.com/mailman/listinfo/towertalk
>
> _______________________________________________
>
>
>
> _______________________________________________
> TowerTalk mailing list
> TowerTalk@contesting.com
> http://lists.contesting.com/mailman/listinfo/towertalk
_______________________________________________
_______________________________________________
TowerTalk mailing list
TowerTalk@contesting.com
http://lists.contesting.com/mailman/listinfo/towertalk
|