[TowerTalk] Vertical base insulator material (rename)

[Bob Maser]

I used Oil filled Nylon solid rod that I got at McMaster & Carr.  I used it 
on each of the 3 legs on a homebrew version of a HYGain Hytower.  It has 
been up for over 3 years and I have had absolutely no problems.  My Hytower 
is unguyed and I climb it whenever I need to fix something.  The lattice 
structure is made of 27 feet of Rohn 25 and the stinger goes up from there 
for a total height of 53 feet.  BTW, Zero 5 verticals use the Oil filled 
Nylon for their insulated bases.  It is a pukey green color and has 
excellent electrical properties and isn't affected by moisture or sunlight. 
Good stuff and cheap.

Bob W6TR
----- Original Message ----- 
From: <vhfplus at bmg50.com>
To: "Jim Lux" <jimlux at earthlink.net>
Cc: <vhfplus at bmg50.com>; <towertalk at contesting.com>
Sent: Wednesday, April 02, 2008 2:02 PM
Subject: [TowerTalk] Vertical base insulator material (rename)


> That's an interetsing suggestion, Jim, but since I have no experience with
> such material I will probably avoid anything that requires engineering.
>
> I do have a large quantity of rod material that was used in machining
> supports for strip-line in 2GHz (PCS) filters but I think that may be a
> bit too small in diameter. It looks quite similar to G-10 but has, if
> memory serves, a different dielectric constant value. I do not recall
> exactly what type of material it is and certainly don't remember anything
> about it's physical characteristics.
>
> W5TM's suggestion about contacting a tower company about old AM tower
> insulators is something worth pursuing...thanks!
>
> 73,
>
> Jack, W6NF
>
>> vhfplus at bmg50.com wrote:
>>> I want to put up a 65-foot base insulated vertical, likely using Telex
> T-15 tower (similar to Rohn 25 but a bit larger). I have a copy of
> W0UN's
>>> note about utilizing G-10 rod as insulators but would like additional
> information. Does anyone on the llist have personal experience with
> such
>>> a
>>> base insulator system?
>>> I am aware that there are commercial insulators available but those are
> cost-prohibitive for my meager budget (the G-10 rod will be expensive
> enough for my wallet).
>>
>> You don't necessarily need G10. You could use anything that is an
> insulator and has the needed mechanical properties. Granted, acetal
> copolymer, Delrin, isn't cheap either, but you could potentially use
> something that isn't made with Glass or Epoxy (e.g. would linen
>> reinforced phenolic work?)
>>
>> the glass composites have the advantage of good high temperature
> performance, but in your antenna application, that's probably a
>> non-issue.  Likewise,  fire resistance.
>>
>> There's also other forms of structural fiberglass that might be
>> interesting to consider.  You can get I-beam made of fiberglass, for
> instance (Extren is one brand). Cost for fiberglass structural material
> is comparable to aluminum, as is the strength (the stiffness is about
> half).
>>
>> So, you could make a sort of triangular sandwich that sits beween the
> bolts sticking up from the base and a copy of a usual baseplate bolted
> to the top of the sandwich. One would need to do some engineering to
> make sure that it won't fall over.
>>
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