[TowerTalk] Routing coax across roof (long)

Pete Goudreau goudpj@mac.com
Wed, 13 Feb 2002 22:34:48 -0600


A question to the list.

>From a planned antenna installation on a chimney, coax (BuryFlex) 
needs to be routed roughly 10' along the adjacent sloping roof 
surface to a ridge where it needs to run about 20' to the gable peak 
where it can run down an unrelated fiberglass mast and then to the 
ground along with a couple of other feedlines.

The problem I'm trying to find a simple solution to is one of 
protecting the shingles from damage as a free coax run would cause a 
working back and forth across the shingles in the wind over time.  
Anchoring the coax seems to be a good solution but with what?  And 
how to do it so the wind won't lift the whole line and damage the 
shingles or cause a leak?

An alternative seems to be to rig sleepers over and along the ridge 
so that they don't have to be anchored but how to keep the whole 
thing from lifting in the wind and causing damage anyway?  And what 
would they be made of?  Commercial sleepers are PVC but meant to lie 
flat on a flat roof, not sure it'd be a good choice in this 
application.

Thought about running a cable directly from the lower chimney mount 
to the fiberglass mast (pretty much a level run) and having it 
support the feedline, as a catenary, but the tension required is in 
the hundreds of pound range for a sag of a foot or more.  Not sure I 
want to subject the chimney to any more loading than is necessary and 
it's a bit of a side load on the fiberglass mast, too.

So, I'm pretty much out of options.  Is there some commonly available 
roofing item that makes this an easy thing to do or is there some 
other way to do this that I'm missing?

Running in to the attic space is not an option, I think, as there's a 
gas line for the furnace there and lightning wouldn't be a good thing.

This feedline, and the others it meets up with at the fiberglass 
mast, are to be grounded via Times ground kits, through a Harger #301 
clamp, to a copper clad ground rod where they come to the ground and 
are then buried around to the master ground bar at the service 
entrance.  This ground rod is part of a lightning ground field as 
well.

Any suggestions, thoughts, pointers, etc., are greatly appreciated.

Thanks,
Pete Goudreau, AD5HD

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