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