Is 78% the correct velocity factor for RG8X coax?

that is what is listed in the belden catalog

"AK" wrote in message news:KRUZf.88176$oL.627@attbi_s71...
Is 78% the correct velocity factor for RG8X coax?

Thanks Dave. The only Belden catalog info I could find on-line didn't list
the VP. Is there a link for full Belden info you could give me? AK

i have a paper catalog, don't know about on-line links for them.

"AK" wrote in message
news:eWUZf.88181$oL.84498@attbi_s71...
Thanks Dave. The only Belden catalog info I could find on-line didn't list
the VP. Is there a link for full Belden info you could give me? AK

i have a paper catalog, don't know about on-line links for them.



All the info in your paper catalog is available online at belden.com
.. All the original poster has to do is click on " Catalog " , then the
" e-catalog " and then type in his cable type, ( RG8X) in the search
window. Belden will then display the one type of RG8X cable they make,
their number 9258. If one then clicks on this number, the complete
specs will be displayed. Just scroll down the specs and one will find
the velocity factor of Belden's RG8X is 82%.

http://bwccat.belden.com/ecat/jsp/In...1=undefined&P2
=undefined&P3=undefined&P4=undefined&P5=undefined& P6=undefined


Ed K7AAT

My experience is that the velocity factor of foam dielectric cable like
RG8X varies considerably from batch to batch and manufacturer to
manufacturer. Apparently they have poor control over the foam density in
the manufacturing process. For any application where it really matters,
you really have to measure it for the particular piece of cable you'll
be using.

Roy Lewallen, W7EL

AK wrote:
Is 78% the correct velocity factor for RG8X coax?

My experience is that the velocity factor of foam dielectric cable
like
RG8X varies considerably from batch to batch and manufacturer to
manufacturer. Apparently they have poor control over the foam
density in
the manufacturing process. For any application where it really
matters,
you really have to measure it for the particular piece of cable
you'll
be using.

Roy Lewallen, W7EL
====================================

And the same applies to impedance Zo and attenuation.
----
Reg.

Reg Edwards wrote:
And the same applies to impedance Zo and attenuation.

How much could the Z0 vary for "50 ohm" coax?
--
73, Cecil http://www.qsl.net/w5dxp

"Cecil Moore" wrote in message
. com...
Reg Edwards wrote:
And the same applies to impedance Zo and attenuation.

How much could the Z0 vary for "50 ohm" coax?
--
=================================

For coax, Zo = 60 * VF * Ln( D / d )

So Zo varies as VF varies.

You'll just have to measure VF or Zo.

Similar for attenuation.
----
Reg.

Cec,

Alternatively, place orders for one or two reels of coax with all USA,
Japanese, Chinese, Korean, German, French, Russian, British cable
manufacturers.

When your back yard is stacked high with full cable reels, cut off a
measured length of cable from each real, lay them in straight lines on
the ground and measure the velocity factors using a hand-held antenna
analyser at around 10 MHz. You will also need a good steel measuring
tape and a sharp cable cutter. Don't use an axe!

Discard outliers of the distribution - they are probably faulty. Use
your pocket calculator to find the average, max and min, and the
standard deviation and you will have the answer to your question.

Then set up a shop.

But I'll save you the trouble and make an uninformed guess. The
Standard Deviation will be around 4 percent of the VF with the 3-Sigma
limits at plus and minus 12 percent.
----
Reg.