[TowerTalk] Re: TowerTalk Digest, Vol 11, Issue 56

[Pete Smith]

At 12:01 PM 11/20/03 -0500, Bill Fuqua wrote:
>What is so great about nonmetallic towers?
>I seem to be missing something here.  They will not stop lightning and I 
>suspect that if they are hit.
>And strong electric fields develop across any of the nonmetallic members 
>the material may just
>explode due to the internal stresses in the "dielectric" bonding material.
>I can see lighting hitting the antenna and going down the feed-line and 
>damaging the tower along the
>way.   Do they mention the dielectric strength of the tower or resistance. 
>Is it non-conductive?


I note that in the installation instruction book they mention that "proper 
precautions" must be taken against lightning to avoid severe damage to the 
antennas or the tower.  Sounds like confirmation of this concern.

I'm also not sure whether a tower made of this stuff would appear to be a 
conductor in the field of the antennas or not.  I do recall that when 
carbon-carbon was first considered for aircraft components one concern that 
had to be worked through was whether the debris in the event of a crash 
would cause disruption to nearby electrical circuits through conductive 
fallout.  I think the US also has some bombs that are designed to kill 
electrical distribution systems through scattering conductive carbon fibers 
across switch and transformer yards.


73, Pete N4ZR
The World HF Contest Station Database was updated October 29.
2469 stations are listed -- 29 new and over 100 updated.
Are you current? www.pvrc.org/wcsd/wcsdsearch.htm