[BC] about STL dishes and jumpers

[Cowboy]

On Thursday 11 November 2010 08:24:51 am donroden at hiwaay.net wrote:
> Quoting Michael Patton <tech at michaelpatton.com>:
> It's almost a cliche that three engineers will give you three
> > mutually-exclusive opinions as to what some problem is caused by, and
> > all of them will swear on their mother's grave that theirs is right and
> > only a "ignorant, pusillanimous SOB" could ever think otherwise.
> >
> > Mike Patton, owner, Michael Patton&  Assoc.

> Damn !!   Now I gotta find a dictionary.   ( grrrrrr )

 Me too !
 I'd NEVER call someone something where I didn't know what the
 words meant !

 I suppose it's possible to install in such a way that this common
 failure is less likely, but mechanical theory says, and MY experience
 bears it out, that any breeze at all will vibrate the tower, the line,
 the antenna, and not synchronously. The solid outer is the weakest
 part, so fails first. A soft jumper, just like a motor mount, only needs
 enough flex to withstand this vibration and not break.
 Hopefully, it lasts long enough for the jumper to dry out and fail.
 A failed jumper is much cheaper to replace than the main line !

 I've even seen situations ( though I can't remember why ) where the
 solid outer HAS failed, but there was enough torque at the connector
 to maintain a connection of sorts, and the system had not failed.
 Once disturbed by a climber ( me, of course ) the failure became
 apparent.

 I suppose it's possible to install in a way that this doesn't happen,
 without a soft jumper, but I haven't seen it.


-- 
Cowboy