[sci.electronics] Thin Ethernet/Coax

jmc@ptsfa.UUCP (04/11/87)

We want to hook up a SUN 3/50 workstation in a cubicle that is wired
for RG-59 coax and our thin ethernet is RG-58.  We therefore have a
impedance mismatch since one coax is 50 ohm and the other is 75 ohm.
Someone told us that if the distances were small we could ignore
the mismatch.

We've been unable to find a suitable impedance matching transformer.  
Does anyone know if we really can live with the impedance mismatch 
and if so for what length wire or know a place that sells impedance 
matching transformers?

-- 

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uucp={ihnp4,dual,qantel}!ptsfa!jmc
As SuperChicken says: "You knew the job was dangerous when you took it."

byrnes@ge-dab.UUCP (04/13/87)

I'm not sure if the difference in cables will
effect your workstation, but I'd reccommend
against using the wrong cable.

We had a problem where someone picked up a
75 ohm terminator instead of the 50 ohm.
(by mistake).
It took us almost 4 hours to find the problem,
since it didn't show up right away.  It was 
installed during low load times and the few 
workstations which were running seemed ok.
Later when everyone went to work the network
would bomb intermitently.
Replacing the 75 ohm terminator with the
50 ohm one solved all the problems.

Good Luck,
Arthur

                                             Arthur J. Byrnes 
UUCP:   ...!mcnc!ge-rtp!ge-dab!byrnes        General Electric
GEnet:  advax::byrnes                        1800 Volusia Ave, Rm 4412
Voice:  +1 904 258 2507                      Daytona Beach, FL 32015

Disclaimer; These views are those only of the author, Arthur.