On Mon, Oct 21, 2002 at 11:17:33PM -0500, Jon Ogden wrote:
> on 10/21/02 9:32 PM, Bob Nielsen at nielsen@oz.net wrote:
>
> > RG-213 has a non-contaminating jacket, not a direct burial jacket. As
> > I recall it is practically identical to one of the RG-8 versions and I
> > would expect that the loss figures are identical. In this respect, I
> > am referring to what was once a MIL-spec cable, but the term "RG-8" is
> > now applied to quite a few other cables in the .405 diameter class (as
> > is also the case with RG-6, RG-58 and RG-59, etc.)
>
> There seems to be a lot of disagreement on this "direct burial" thing. My
> RG-213 says it clearly on the jacket: "Direct Burial"
>
> No, there's no goop in there, but according to what I have been told by the
> folks at Cable Experts (where I got the cable), anything with a polyethelene
> jacket is essentially capable of direct burial. PVC jackets such as RG-8,
> are not rated for such. I will double check my information with them since
> they are in my area and I regularly pick stuff up from them.
>
> RG-213 is a mil-spec cable yes. It has a different dielectric than RG-8.
> RG-8 typically has a foam dielectric. Has less loss than RG-213 but can't
> handle the power.
It IS confusing.
MIL-SPEC RG-8/U had a polyethylene dielectric, the same as MIL-SPEC
RG-213. I recall that the original had a contaminating PVC jacket, but
I think there was a later version which had a non-contaminating PVC
jacket. Accoding to the Belden catalog (which agrees with my
recollection,) MIL-C-17 RG-213 has a non-contaminating polyvinyl
chloride jacket, not polyethylene.
RG-8 was replaced by RG-213 in the mil-specs back (I think it was in
the late 50's or 60's), just as RG-9 was replaced by RG-214 and RG-55
was replaced by RG-223, etc.
Currently, cables which meet Mil-C-17 have a M17/xxx designation,
instead of (or in addition to) an RG- number. Many manufacturers have
(unfortunately, IMHO) applied RG designations to variations which are
sometimes quite different than the original RG designation signified.
This doesn't mean that they are inferior cables (quite often they have
significant improvements), but not all RG-xxx cables with the same
number are equivalent.
73,
Bob Nielsen, N7XY
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