[SBE] hole in Heliax

[Mike Langner]

I, for one, am in favor of not replacing what's not broken !

But careful inspection and an HV test to see if there's any carbon on the
inner-to-outer insulator would sure be a good idea.  3" Heliax is rated for
lots and lots of volts -- which is good -- but if there's any carbon that
could become deposited on the inner-to-outer insulator, lots of trouble
could be coming!  Especially if there is a little carbon, if you get a
little moisture in the line the fireworks really begin !

And from at least my experience, at 100 mHz, those splices, if well
installed, work very, very well !

It would be worth replacing a reasonable length above and below the holes --
this will minimize the amount of carbon that may contaminate the Heliax.

If you suspect a "blow-out," may I please suggest checking the regulator,
the pop-off safety valve, and, if they're OK, checking to see if the coax
had a crimp in it?  Riggers are known to crimp or kink Heliax, straighten it
out, hang it, and not tell anybody.  That develops a weak spot.

And then there's always the chance that what you've got is bullet holes!
Unfortunately, not uncommon !! At least that'll mean there probably aren't
any carbon problems!  Are the holes near a tower light?  Hello, target
practice !!

Still, I'd sure carefully inspect for carbon tracing/tracking !!

Good luck !!

Mike/

Mike Langner, CPBE
Albuquerque, NM
______________________


-----Original Message-----
From: sbe-bounces at sbe.org [mailto:sbe-bounces at sbe.org]On Behalf Of Gary
Blievernicht
Sent: Wednesday, August 06, 2008 12:56 PM
To: sbe member discussion mail list
Subject: [SBE] hole in heliax


We have two holes in the 3" (air) heliax run to our stand-by antenna. The
antenna is at the 500 foot level on our tower, the holes are about six feet
apart at about the 300 foot level.  Might have been lightning?  Might have
blow out when we applied power on Friday for the first time in months? .
The line had been holding pressure until last Friday, so, I'm figuring it
blew out.

Wonder if we should just splice out twenty-five feet of heliax or if we
should, at considerably more expense, replace the entire run.

Or try the splice and see what happens?

I can send anyone a pair of pictures if you are interested.




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