[1977] in linux-net channel archive
Re: Networking without a hub or a router/repeater(was Re: ``Networking'' via SCSI)
daemon@ATHENA.MIT.EDU (Ed Carp)
Sun Feb 25 11:25:00 1996
Date: Sun, 25 Feb 1996 10:12:36 +0000
From: Ed Carp <erc@dal1820.computek.net>
To: Paul Gortmaker <gpg109@rsphy1.anu.edu.au>
cc: Lincoln Myers <lincoln@netapp.com>, linux-net@vger.rutgers.edu
In-Reply-To: <9602240157.AA07691@rsphy6.anu.edu.au>
On Sat, 24 Feb 1996, Paul Gortmaker wrote:
> I don't have the specs here for RG-58 coax, but at 10MHz you can run
> a signal 185m (max 10B-2 segment) and still get a signal out the other
> end with less than about 10 dB loss. Now if you up the frequency to
> 100MHz, the loss of RG-58 scales dramatically, and only short runs
> would be possible without suffering complete signal loss. Somebody
> with the specs handy can post how many dB/m you lose with RG-58 at
> both 10MHz and 100MHz.
It's about 1.5 dB at 10 MHz and about 5 dB at 100 MHz. If you have an
ARRL Handbook handy (available in most libraries) there's a chart in the
chapter entitled "Transmission Lines".
Also, you might want to make sure that RG58 is what you want. The
impedance of RG58 is 50 ohms (give or take), while I believe that those
BNC connectors are designed to feed 75 ohms. Try a piece of RG74 or
Belden 9275.
--
Ed Carp, N7EKG Ed.Carp@linux.org, ecarp@netcom.com
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