[TowerTalk] burying cable
Chuck
dietz@texas.net
Sun, 08 Feb 1998 09:16:29 -0600
By the way, farm & ranch stores sell 100' coils of flexible water pipe which is
cheaper and way better than garden hose for this purpose.
Chuck, KZ5MM
DavisRFinc@aol.com wrote:
> In a message dated 98-02-08 00:45:10 EST, you write:
>
> << Why bother to hose your coax? If it doesn't need armor, get direct burial
> and be done with it! Unless you provide drainage, air, or desiccant it
> will get wet.
> Jim Bradshaw, ac6tk >>
>
> I have to agree with Jim. The original inquirer mentioned RG213 and I believe
> one other PVC jacketed cable he wanted to bury. There is a great
> misconception among many hams (and I suspect only few of them might be on TT)
> that a PVC IIA "non-contaminating" (vis a vis non migrating) jacket is direct
> burial. In fact I see it claimed in ads. PVC of any type compound is NOT
> direct bury. Now, if you put it in a garden hose, I'm not saying that in all
> cases you will have problems as some earth conditions, drainage, etc. would be
> better ambients than others. However, I will say that there is a good chance
> that the hose will enhance production of moisture inside and also many hoses
> would chemically deteriorate over time. PVC is not necessarily a problem on a
> SHORT time basis inside any conduit that creates moisture; however the safest
> approach, I believe, is a polyethylene jacket of high polymeer density in the
> area of .951. This is the type Polyethylene ("PE") that a conscientious
> supplier such as Wireman or DAVIS RF stocks. A "flooded" PE is expensive and
> in my opinion is not needed, particularly if you put a non-flooded PE in a
> conduit as the "flooded" aspect is primarily to seal accidental piercing of
> the outer jacket by errant shovels, etc. (and by the way, as of recent TT
> postings I should add chain saws as they now seem to have a new ham
> application - McCullock, etc. will want the ham marketing lists HI). Press
> Jones of the Wireman gave excellent input on TT a few weeks ago as to the
> proper installation of conduit. If you are not concerned about accidental
> damage by errant shoveling, you do not need a conduit with quality PE
> jacketing. A quality formula Polyethylene does not have a plasticide
> ingredient (phthalate filler added to enhance molding/extrusion) which is the
> prime cause of migrating contamination of the dielectric. It is also a real
> tough, abrasive and cut resistant jacket (use a real sharp razor when doing
> connectors). In some cases you can obtain a 50 ohm cable with PE jacket that
> has all the other spec's of a 213 or RG8 at only about 20 cents more per foot
> (vs. the cost of an outer PVC conduit). Wireman and DAVIS RF and our dealers
> carry "Bury-FLEX" Tm designed by DAVIS RF which gives you the PE outer jacket
> and lower loss at VHF and UHF (and obviously HF), as compared to RG8 or 213
> and very close to LMR 400, along with flexibility better than LMR or 9913.
> This item is highly appreciated by many, and serves some otherwise unserved
> needs, including its economic price. Lastly, if you want to just lay BURY-
> FLEX Tm on the ground, in the woods, etc. it has proven undesirable to rodents
> based on my testing, at least in New England with squirrels, woodchucks,
> beavers, etc. If you live in Florida, no guarantess about alligators. HI !!
> 73, Steve Davis, K1PEK, DAVIS RF Co., commercial wire/cable, custom design,
> discounts to hams, "FLEX-WEAVE" Tm.
>
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