I love it! Murphy should have a price on his head! Chuck W5PR
On Thu, Oct 5, 2017 at 7:13 AM Guy Olinger K2AV <k2av....@gmail.com> wrote: > Coming from an ancient Telco background which included keeping microwave > waveguides dry for AT&T, unless you are willing to pressurize the conduit > at one end and allow air to exit at the other, AND insure that the air is > dry enough to not condensate at your coldest possible ground temperature, > or run it with an unbroken slope to a point where water drains without > pumping and or can be suctioned, then make these assumptions: > > 1) Permanent performance and very long life is desired and outweighs cost. > If you move a lot and are putting up stuff at rental housing you probably > need not worry. Just remember to start with new coax and cable at the new > rental place. Throw away the old stuff. Then mark this read and move on to > the next posting. If you think you are retiring at your place of residence, > and if lucky want it to work without a worry for the next 30 years absent > direct lightning strike, then read on. > > 2) All conduits will fill with water. That is their NATURAL state unless > you specifically and effectively mitigate it. At any time other than first > installed, filled with water is their most probable state. > > This leaves the main usefulnesses of the conduit as > > a) Critter protection, and > > b) Cable replacement, if the conduit is large enough and water-proof pull > ropes are left in conduit, a method of adding or replacing cables that > avoids redigging and leaving deprecated cable in the ground. These are > significant long-term advantages, and many find those more than enough > reason to use them. However....... > > 3) Even in conduit all cables must have permanent, water-proof jacketing. > Most cable has jacketing that is not rated for permanent submersion, meant > for indoor use. > > Polyethelyne (PE) jacketed or hardline cable is really the only commonly > available choice for coax with portions permanently submerged. Flooded is > nice, but probably overkill INSIDE CONDUIT if the jacketing is PE or other > permanently waterproof material. ***RG213 does NOT conform.*** Any > miscellaneous plastics do not conform. There are cables manufactured with > ham-uncommon materials to telephone company specifications, FOR DELIVERY TO > TELCO, that have all the water stuff worked out just fine. But BEWARE > knockoffs and batches for retail that mfr knows will never be sample tested > by telco. Or for that matter cable that failed telco tests and was put on > the retail market to recover costs. > > High current rotator motor leads (as opposed to control leads) should use > the commonly available UG series direct-buriable power wiring available at > home improvement stores. Less voltage drop, permanent and rated for wet > environments. > > 4) splices or cable terminations should be made indoors and elevated where > waterproofing failure will not allow water to get inside the PE jacketing. > Some manufactured multiconductor cables will have BOTH external and > internal insulation PE or teflon. Do not locate splices in conduit. You're > just asking for it. Even if 9 out of 10 get away with it, be assured you > will be # 10. Murphy KNOWS all you've done, knows all the contest and > DXpedition dates, AND has a malevolent nature. > > 73, Guy K2AV > > > On Thu, Oct 5, 2017 at 8:49 AM, Dale Putnam <daleput...@hotmail.com> > wrote: > > > I agree with Ken, with only one option, and that would be if the conduit > > is open on both ends.. allowing free air flow thru. That situation, MAY > > help dry the water from sitting on the cable, depending on the average > > humidity at the underground temp. Warm air from inside.. to cold air > > outside may not work out well either. > > > > > > > > Have a great day, > > --... ...-- Dale - WC7S in Wy > > > > "Actions speak louder than words" > > 1856 - Abraham Lincoln > > > > > > ________________________________ > > From: Topband <topband-boun...@contesting.com> on behalf of Ken > Claerbout > > <k...@verizon.net> > > Sent: Thursday, October 5, 2017 6:19 AM > > To: topband@contesting.com > > Subject: Re: Topband: underground cables question > > > > As you have found out, it's impossible to keep water out of a conduit > like > > that. I use direct bury cabling and put it directly in the ground. > > Granted the cable is flooded, but putting in back in the conduit ensures > it > > will sit in some water, something I would try to avoid. > > > > 73 > > Ken K4ZW > > > > > > -----Original Message----- > > From: John <beaumo...@beaumonts.karoo.co.uk> > > To: topband <topband@contesting.com> > > Sent: Thu, Oct 5, 2017 4:11 am > > Subject: Topband: underground cables question > > > > Hi all, some years ago I buried a 4 inch conduit about a foot deep in my > > field , inside I run a control wire and a coax line RG213 to a 160 m > > vertical the feeder was a total of 5/4 wavelength long about half of it > in > > the conduit, it was used as one line for a pair of verticals spaced 5/8 > > wave apart. When first installed it worked very good but after a while I > > noticed it dropped off and I suspected water ingress. An insulation test > > with 1000v from my electricians test equipment showed indeed a fall in > > insulation resistance. > > > > So my question is I have a couple of large reels of commscope F1160 BEF > > flooded 75 ohm > > do you think I could put it in the same conduit which has allowed some > > water in or would you make alternative arrangements . I realise it a > direct > > bury coax but appreciate advice. > > > > I wish to get the two verticals going again will use 1 X 3/4 line above > > ground 1x5/4 line part in conduit and a 1/2 wave to switch in and out > above > > ground. > > > > regards > > > > > > John Beaumont > > G4EIM > > > > > > _________________ > > Topband Reflector Archives - http://www.contesting.com/_topband > > Topband Archives - Contesting Online Home<http://www.contesting. > > com/_topband> > > www.contesting.com > > Topband Mailing List Archives. 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