nanog mailing list archives

Re: Presumed RF Interference


From: David Lesher <wb8foz () nrk com>
Date: Sun, 5 Mar 2006 18:00:36 -0500 (EST)




That is already half of a solution:

Go for fiber. That is imune to both ground and RF problems. Avoid
ground connections between the equipment.

Replace ethernet with fiber. Break serial lines with optical isolators.

Yes, fiber will solve ground loop problems. And this smells like
a ground loop issue. But at this juncture, I don't have enough
specifics to recommend ma$$ive changes.



Cut the ground wire in your power cords but ground the equipment directly
to a metal frame.

I would NEVER tell a client to do this. 
That could easily kill someone.

Avoid ground loops: Between two computers you have a ground connection
via the powerline ground. Connect them via RS-232 and you have a second
connection via the RS-232 ground. If your power ground is bad then you
might run amperes through the RS-232 ground that results in Volts, more
than your signal level, maybe.

I don't recall mention of RS-232,. but yes, this is the classic
example of ground loops.


-- 
A host is a host from coast to coast.................wb8foz () nrk com
& no one will talk to a host that's close........[v].(301) 56-LINUX
Unless the host (that isn't close).........................pob 1433
is busy, hung or dead....................................20915-1433


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