If I were a coax manufacturer I would down play the importance of a
non-contaminating jacket as well. Can you say "contamination is our friend
- fire up the coax machine"?
I well remember seeing the black copper shield and dielectric inside Belden
8214 coax after being in use a few years. The loss was about 3X the new
spec.
Someone, somewhere, along the line thought non-contaminating jackets were a
good idea or there would be none made today.
8267 is indeed a non-contaminating RG8 sized coaxial cable with good braid
coverage and solid PE dielectric. It is tough as nails and can be expected
to last a long, long time, even in a flex loop. Yes, the loss is higher
than the newer foam cables but for modest run lengths, it certainly has a
place in many hf applications.
73,
Geald K5GW
In a message dated 4/25/2010 10:04:05 A.M. Central Daylight Time,
jim@audiosystemsgroup.com writes:
Roger said,
>It appears to be pretty expensive for what is apparently the equivalent
>of the old standard coax with a solid PE dielectric, bare copper
>braid/shield, and 5" bending radius.
As best I can tell from the Belden catalog, it's essentially the same as
8237, but with a non-contaminating jacket, and a dielectric that gives
lower loss at UHF (but both are solid PE). The cost premium at places
like Markertek (a broadcast house) is about 22%. Sorry John -- their
catalog lists only 500 ft and 1,000 ft spools.
But that brings up an interesting question. When I talked with Belden
engineers several years ago, they sort of downplayed the importance of a
non-contaminating jacket, saying that all black PVC was pretty UV
resistant. If that is true, given that the result of contamination is a
degradation of the dielectric, and that loss at HF and VHF is almost
entirely copper, should we still CARE about a non-contaminating jacket on
cable that will be used only at HF?
Important note -- I'm not stating this as fact, nor as a request for
"opinions" or "what you've always heard/read," but as a question to those
who may have seriously studied this and have real information on the
topic.
73,
Jim K9YC
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