23 Jan
2018
23 Jan
'18
12:27 p.m.
On Jan 23, 2018, at 3:19 PM, Noel Chiappa via cctalk
<cctalk at classiccmp.org> wrote:
The Ethernet spec says that the cable OD is in the range .365 to .415 inch, which is 9.27
to 10.54 mm. The nominal OD of RG-8/U is .405 inches, or 10.28 mm, which is within spec
for Ethernet cable.
One place where the two cable specs differ is in the velocity factor, 0.66 for RG-8/U and
0.77 for Ethernet cable. That relates to the dielectric -- solid polyethylene for RG-8/U
and foamed material (unspecified) for Ethernet. Also, Ethernet requires a solid inner
conductor (for the tap) while RG-8/U may come stranded. (Maybe only in some variants,
I'm not sure.) And there are the stripes, of course, but those have no electrical
significance. You can use a tape measure if you don't have the stripes.
paul
From: Grant Taylor
I can fairly clearly see the RG-8/U on the side
of the cable that David
is holding ... Sure, there was probably a better alternative that came
along after, with better shielding and marking bands.
You keep mixing up the 3 Mbit and 10 Mbit. _They were not the same_. (I
_really_ need to retake those photos with a ruler in them...)
The stuff with better shield, marking bands, etc is 10 Mb; it's about 1.05cm
in diagmeter. The black stuff (the stuff Dave is holding in the video) is 3Mb;
the piece I have is .95 cm.