At the suggestion of WV4P, I spoke with a Rohn engineer about the
incompatibility of their TB45B torque bars and 1/4 in EHS cable. See here:
https://www.3starinc.com/manuals/ROHN_Torque_Bar.pdf
All Rohn 45G tower designs require 1/4 in EHS on at least one of the
guys. My 50 ft install uses a single 1/4 in EHS guy, presumably
precluding the use of torque bars. He was not certain, but suspected
the issue was simply that the shackle required for 1/4 in EHS would not
clear the hole in the bar. I also have this guy bracket:
https://static.dxengineering.com/global/images/chartsguides/r/roh-ga45gd.pdf
except that mine has $1000+ worth (!) of torque bars in place of the
ringfills and eyelets. I asked about ordering those to replace the
torque bars and he said it would be cheaper to just buy the entire
bracket assembly. He also said to investigate getting substitute eyelet
hardware from another vendor.
I'm open to suggestions.
Mike WB2FKO
On 6/9/23 21:27, Ron WV4P wrote:
When the Catenary weight of 1/4" EHS changes the angle of the torque bar to
destroying the bracket VS resisting twist it all makes sense... Adding
larger shackles compounds the issue.
Likely not an issue with your short tower but worth a call to Rohn.
Ron, WV4P
On Fri, Jun 9, 2023 at 8:21 PM Steve Maki <lists@oakcom.org> wrote:
That's idiotic, or at least short sighted.
Use the biggest pin shackle that will fit in the torque arm, and 1/4"
big grips (preforms) with thimble in the shackle. This makes it easy to
remove a guy wire temporarily whenever needed.
As has been pointed out often, the torque arms don't do much for
rotational resistance, but if you have them, use them. It makes a nice
install.
-Steve K8LX
On 2023-06-09 8:34 PM, Mike H wrote:
I acquired some used Rohn 45G in very good shape and will be going up
50 ft. Antenna will be stacked 2 x 9-el for 2m. I'm following the Rohn
engineering guidance very closely: base is a new R-SB45G buried in the
prescribed concrete block along with GAR30 guy anchors, also in
concrete. I have the older style guy bracket for 45G that has (very
expensive!) TB45D torque bars
<
https://www.3starinc.com/rohn_45g_torque_bars_for_use_with_guy_bracket_r-tb45d.html>
along with several hundred feet of brand-new 1/4 in EHS for the guys.
According to the Rohn instructions, however, I can't use EHS cable
that's greater than 3/16 in:
https://www.3starinc.com/manuals/ROHN_Torque_Bar.pdf
This means I'd have to buy either smaller EHS cable or their newer guy
bracket that doesn't use torque bars. I'll do this if I have to, but
I'd sure like to understand why 1/4 in EHS is a deal-breaker for the
torque bars. QTH is north Florida so I want to make the setup as
storm-proof as practical. Any insight appreciated.
Mike WB2FKO
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