RE: A few Q's

["Tesla list" <tesla-at-pupman-dot-com>]

Original poster: "Terry Fritz" <twftesla-at-qwest-dot-net>

Hi Jim,

A lot depends on what you want to ground.  For DC and 60Hz AC, there is
only one easily fixed problem.  For RF, if the block is big and has lots of
surface area, it will be fine.  Even though the resistance may be higher
than say a block of pure silver or gold :-))  if it has lots of area the
resistance will be low regardless.

Aluminum can form very thick high resistance oxide layers.  Aluminum oxide
is a very good ceramic insulator.  Either get some rough sand paper and rub
through the gray hard layer down to the bright shiny pure aluminum for the
connections or get "No-Ox" used for aluminum electrical connections.  This
is especially important if you are using it as a safety ground that may
have to take high AC line currents.

Cheers,

	Terry

At 08:36 PM 3/12/2002 -0500, you wrote:
>Hi Terry (and others),
>In regards to "skin effect"-
>If that is the case (aluminum is lossy) then a large chunk of aluminum
>would be a bad choice for a grounding block?
>What I needed was a place to "tie in" all my RF grounds to one common
>point
>and then attach that point to my earth pole in the yard. This, in an
>attempt to avoid multiple, long lengths of heavy cable to the ground
>rod. I was going to grab a big hunk or cast iron or steel from work but
>it was 
>suggested to me than aluminum would be a better choice. I ended up
>grabbing an old cylinder head that is almost 100% aluminum.
>So is this a good choice or would steel or cast iron be better after
>all?
>Thanks,
>Jim Layton
>