Path: utzoo!attcan!utgpu!watmath!iuvax!purdue!tut.cis.ohio-state.edu!rugby.cis.ohio-state.edu!butzer
From: butzer@rugby.cis.ohio-state.edu (Dan Butzer)
Newsgroups: comp.dcom.lans
Subject: Re: RG58A/U vs. RG58/U ...
Keywords: RG Ethernet
Message-ID: <56263@tut.cis.ohio-state.edu>
Date: 28 Jul 89 14:01:39 GMT
References: <4074@lindy.Stanford.EDU>
Sender: news@tut.cis.ohio-state.edu
Reply-To: Dan Butzer <butzer@cis.ohio-state.edu>
Organization: The Ohio State University Dept of Computer & Information Science
Lines: 25

In article <4074@lindy.Stanford.EDU> strattan@lindy.Stanford.EDU (J. Seth Strattan) writes:
>I've wired a couple of RG58A/U Thin-nets and they all hum along quite
>happily.  I know there is a RG58/U although I've never run it.  What
>is the difference between the two.  I have a hunch it is a difference
>in dielectric .. yes?  Is the difference relevant to Ethernet
>installations?

RG58/U cable violates 10Base2 in a couple ways.  It's nominal impedance does
not fall within 10Base2's 50 ohms +/- 2% requirement. (ie, Belden RG58/U
has a nominal impedance of 53.5 ohms.) Also, RG58/U has a solid center 
conductor, instead of the stranded center as specified.  There may be other
violations, but these are the 2 that come to mind.

You will most likely find that RG58/U cable will work as long as you don't
push anything right to the limit, but you don't want it !!!   
Long ago, some of it was installed around here, and it has proven to 
be unreliable compared to the A/U cable.  The solid center wire
breaks easily at the BNC connector.  I plan to replace all of the 58/U 
we have as soon as I can.

						--Dan
-=-
Dan Butzer - The Ohio State University Dept. of Computer & Information Science
             Net:   butzer@cis.ohio-state.edu     Voice: (614)292-7350
             Snail: 2036 Neil Ave Mall, Room 245, Columbus, Ohio, 43210