Re: Networking without a hub or a router/repeater

Paul Gortmaker (gpg109@rsphy1.anu.edu.au)
Mon, 26 Feb 1996 09:51:09 +1100 (EST)


>From "Ed Carp" at Feb 25, 96 10:12:36 am

> 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.

50 ohm cable *is* what you want. People who have tried to stuff an
ethernet signal down 75 ohm "cable T.V." wiring will vouch for that.
(Mind you I am not sure whether they tried 75 ohm terminators as well. 8)

The IEEE 802.2 spec approves coax that is marked as follows:

802.3 10Base2 (50 ohm, stranded tinned core)
RG-58 a/u (50 ohm, stranded tinned core)
RG-58 c/u (50 ohm, stranded tinned core)

The IEEE 802.2 spec does not approve of 50 ohm solid core cables, such
as RG-58 or RG-58 /u coax.

Belden 8259 is equivalent to RG-58 a/u coax.

Paul.