Robert, What you have done should work fine. I have some 3 inch runs
open at both ends, (Screen material over outside ones for those darned
mud daubers) partly as an experiment since having been told by multiple
posters here that condensation would form and get pretty deep. Every 6-9
months I run a dry rag through with the pull rope I left inside for just
in case. So far so good, not a sign of moisture. This isn't exactly
Arid Zona or New Mexico. We get prodigious quantities of humidity in
some seasons. I had originally intended to seal both ends with a packet
of desiccant inside the conduit to absorb moisture but couldn't resist
"the experiment.."
Currently putting in about 600 ft of 4 inch with no drain holes. I have
speculated but not experimented with a small heat source and fan to
circulate warmed air through a long run to dry out moisture from
condensation. I'm still waiting for moisture from condensation. Maybe
this latest long run of 2 each 300 foot pieces will get condensation.
Then I can either use descant, warm air or pull rope with rags. If It
does require remediation I will dry it out, put in desiccant, and seal it.
73,
Patrick NJ5G
On 5/11/2014 11:43 AM, r miles wrote:
Getting ready for two BF runs to the new tower. It will be in PVC.
Since it's out of site I use the white PVC. Costs less than the gray.
The main worry about moisture is temp. variation causing the PVC to
'sweat' inside & eventually to get water in the lowest spot of the
run. My run to my HyTower is apx. 120' in PVC. Downhill all the way
but there's a dip about 20' from the HT. I drilled several 1/8'' holes
on the bottom of the PVC at it's lowest point. The PVC is several
inches below the surface all the run. At that low point I dug a hole
the size of a 1 Lb. coffee can & filled it with pea gravel. Any
moisture will run to the low point & exit thru the holes into the
gravel. I prefer to seal the end where the coax exits at the tower
base. We have lots of nasty insects in W Tn & don't want them finding
a home. Here if you store EMT, PVC or aluminium elements they need to
be taped on the ends to prevent insects from entering. We have 'dirt
daubers' & they can stuff mud 6'' into the ends. A real pain flushing
them out. It hardens like cement. Other bugs like the ends of my spare
Rohn 25 sections as home. I've flushed them & they are taped too.
I learned the value of 'drip loops' in the coax lines coming off
towers. At the old QTH I forgot to add one & one day I discovered a
spoon full of water on the OP desk behind the radio. Whether it ran
inside or outside of the coax I don't know but it managed to find it's
way inside the house.
K9IL
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