[TowerTalk] substandard aluminum?

[Jim Jarvis]

Telrex:  I think there was a period when lighter, stronger
aluminum was available, and was used in production.  This
resulted in different physical resonance conditions, which
in turn resulted in premature failures.  

Which brings us back to Titanex.  Antenna designers aren't
necessarily mechanical gurus.   As many have suggested, there
appears to be a vibration induced fatigue causing the failures.

I'm sure they're neither the first nor last to experience 
this problem.  It'll be interesting to see how they handle
Bruce's failure @ zf2nt.

n2ea
jimjarvis at ieee.org 

-----Original Message-----
From: Michael Tope [mailto:W4EF at dellroy.com]
Sent: Tuesday, March 01, 2005 13:05
To: David Jordan; jimjarvis at ieee.org
Cc: towertalk at contesting.com
Subject: Re: [TowerTalk] substandard aluminum?



----- Original Message ----- 
From: "David Jordan" <wa3gin at erols.com>


> Yes Jim you are correct about Telrex...and the 30yr old TB6EM that I 
> have up at 35 meters is still working
> and  none of the aluminum has broken off.   That's about 10,950 days for 
> those of you that aren't laughing to hard to read the small print!
> 
> Telrex built antennas before the days of PCs. They did it the old 
> fashioned way. They built them to last! 
> 

Dave, 

Junk antennas are not a recent invention. Telrex made some pretty 
shaky antennas too. Back in the 80's KS8S had two of their 3 element
40 meter yagis stacked on a 180' tower. The stainless steel element tips 
were constantly  falling off those antennas. And when the tip were up
there, the antennas didn't seem to work worth a damn although that
may have been a guy wire problem (no insulators). 

Mike, W4EF................