[TowerTalk] WTB Rohn 25G tower insulator

[Andre VanWyk]

Chris,

The insulators would by 30ft up the tower, so although I think this would 
work nice at ground level, doing something like this up there would require 
additional hardware.

I think as of now, the WB0W insulators makes a lot of sense....

73's
NJ0F


-----Original Message----- 
From: Chris
Sent: Tuesday, December 15, 2015 2:07 PM
To: Jim Lux
Cc: towertalk at contesting.com
Subject: Re: [TowerTalk] WTB Rohn 25G tower insulator

Did we ever come to a conclusion as to whether or not a flat sheet (like 1" 
thick or more) of HDPE plastic would work?  Sandwich the sheet between the 
concrete and a flat bottomed pier pin type base.  Obviously taking care to 
insulate the pier pin bolt.

Chris
KF7P








On Dec 15, 2015, at 1:03 PM, Jim Lux wrote:

> On 12/15/15 10:06 AM, Andre VanWyk via TowerTalk wrote:
>> I am getting parts together for a 160m vertical, using Rohn 25G sections. 
>> I am looking for a Rohn insulating tower section. If someone has one, 
>> please drop me an email. I managed to locate one a while back, but sold 
>> it to friend whom I felt needed it more that I did at the time.
>>
>> For my 80m Four Square, I had insulators made out of G-10 fiberglass rod, 
>> but I feel these are not suited for such a tall structure.
>>
>
> Why wouldn't you think it's strong enough.  G-10/FR-4/Garolite is pretty 
> strong stuff.
> The rod probably has more compressive strength than the tubing used in the 
> tower sections. Likewise in shear: there's a lot more cross sectional area 
> resisting the shear force).
> Bending might be the area where it's different, but bending loads on a 
> guyed tower base are pretty low (and zero, with a pier pin type base.
>
> Rohn 25G is 1.25" diameter 16ga tubing. wall thickness is 0.065"
> So the cross sectional area is 1.25*pi*0.065 about 0.25 square inch
> The solid rod will have cross section on the order of a square inch.
>
> Figure steel yield is around 36 ksi, G10 is around 10 ksi, so the 
> compressive strength of both is pretty similar.
>
> (In reality, the failure mode for the vertical tubes is probably buckling, 
> not compression)
>
>
>
>
>> Rohn does not manufacture this item anymore either.
>>
>> 73’s
>> NJ0F
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