Sorry, Mauri, but you are not describing 8X as most of the world knows
it. Your description sounds almost like CATV cable, except that the braid
is aluminum and can range as lean as 40%shielding By definition, the
original 8X was 93.7% bare copper braid over foam PE with a center cond
of bare, 16 gauge stranded copper. The jacket was a Class I PVC.
Variations of this have appeared over the years, but the basics are the
same. The exceptions that relate to your description include a few low
loss types, by us, Times, to name 2, but they all have tinned copper
braid of greater than 90% over the inner shield of aluminum/polyester.
Their power rating is no lower than the basic type.
73,
Press Jones, N8UG - The Wireman, Inc., 261 Pittman Rd, Landrum, SC 29356
<Press@thewireman.com> or <orders@thewireman.com>
800-727-WIRE(9473)(sales)
Tech help 864-895-4195, fax 864-895-5811.Full catalog, images,
descriptions, coax specs,
ordering, at http://www.thewireman.com and super deals, specials,
close-outs etc.,
at THE WIRELINE. Check the CALENDAR to find us at a hamfest!
On Thu, 1 Mar 2001 14:57:00 +0100 "i4jmy@iol.it"<i4jmy@iol.it> writes:
> The reason why an RG8X insn't raccomandable at high power levels is
> because of a shield that's made of a thin aluminum Foil-Polyester
> Tape-
> Aluminum Foil and only very few thin copper wires anot describings
braid shield.
> The foam dielectric hasn't significant losses and a foam cable of
> the
> same size of an RG8X, but with a classic copper braid or a more
> consistent foil (aluminium or copper), would safely withstand much
> more
> than US legal power at 7 MHz, and roughly twice the power of an RG58
>
> expecially at 30 MHz and above.
>
> 73,
> Mauri I4JMY
>
>
> > ---------- Initial message -----------
> >
> > From : owner-towertalk@contesting.com
> > To : <towertalk@contesting.com>
> > Cc :
> > Date : Thu, 1 Mar 2001 08:35:18 -0500
> > Subject : RE: [TowerTalk] Coax Rating
> >
> >
> > Ted,
> >
> > Be careful. Yes, I have had a meltdown as you call it, using some
> > hamfest-grade RG8X on a 100 ft run feeding a 1/2 wave on 40. The
> power into
> > the feed line was likely about 700W. I don't know whether this
> happened
> > while operating on 40 or 15. And here's the caution...you might
> squeak thru
> > with a perfectly flat SWR. But with 3/2 waves I'd bet you will
> not
> have
> > that. Any SWR will significantly increase the probability of
> zapping
> the
> > line.
> >
> > As I recall, the rating is about 300V across that foam dielectric.
>
> Less
> > sure of that than the above. I believe RG58 is actually more
> forgiving than
> > RG8X in terms of power handling.
> >
> > I'm using RG8 now, with a convenient tree to help support the
> weight
> so the
> > antenna doesn't have to see it all.
> >
> > 73/Gary W2CS
> >
> >
> > | -----Original Message-----
> > | From: owner-towertalk@contesting.com
> > | [mailto:owner-towertalk@contesting.com]On Behalf Of Ted & Joyce
> Wilhelm
> > | Sent: Wednesday, February 28, 2001 11:39 PM
> > | To: towertalk@contesting.com
> > | Subject: [TowerTalk] Coax Rating
> > |
> > |
> > | Am planning on trying to put up 3 1/2 waves on 40mtrs. and
> wonder
> if
> > | anyone knows the maximum power that RG8X will handle on a
> relatively
> > | short run less than 100 feet....I know I would probably be
> better
> off
> > | with something like 213 or the like but am concerned with the
> weight
> > | factor....Anyone had any major meltdowns using the lighter feed
> line.
> > | Thanks,
> > | Ted K9HUH
>
>
>
> --
> FAQ on WWW: http://www.contesting.com/FAQ/towertalk
> Submissions: towertalk@contesting.com
> Administrative requests: towertalk-REQUEST@contesting.com
> Problems: owner-towertalk@contesting.com
>
>
--
FAQ on WWW: http://www.contesting.com/FAQ/towertalk
Submissions: towertalk@contesting.com
Administrative requests: towertalk-REQUEST@contesting.com
Problems: owner-towertalk@contesting.com
|