[Towertalk] Connecting grounds to towers

[va3pl at cuic.ca]

I work for a Aerospace Company and we do a lot of Jet engine parts as well
as R&O on them and we use
very high quality Stainless Steel. That stuff is called superalloys. The
base metal is nickel. Sure you don't need that high quality stuff for your
antenna or tower work but this is what we have here in the scrap bin.
I can send a piece to anyone for the asking. You cover the shipping and
packing. The most popular sizes I can see in the scrap bin is about:

4 X 5" - about 0.020 to 0.030" in thickness - weighting about 110 gr
3 1/4 X 11 - about 0.020 to 0.030" in thickness - weighting about 190 gr

Please be warn that stuff is tough. This is not Home Depot SS. This is
aircraft SS!!
Don't ask me for specification of it because I'll not give it to you.
You'll have a hard time drilling holes through it or cutting it. Drilling is
done with the use of carbide drill bits.

73 de Andy - VA3Pl


----- Original Message -----
From: "Floyd Sense" <sentek at sprintmail.com>
To: "Bill Ralston" <n7vm at lgcy.com>; <towertalk at contesting.com>
Cc: <ogden at us.ibm.com>
Sent: Friday, November 14, 2003 11:38 AM
Subject: Re: [Towertalk] Connecting grounds to towers


> In regard to the stainless steel shims - I recently did the same, after
> spending a lot of time finding the darned stainless steel.  I finally
> located some at a large sheet metal shop.  They had some .002 and .005
stock
> on hand, rolled up in tubes.  According to them, they'd had it for several
> years and no one had ever asked for it before.   I also ran across some
> small stainless strips in a local "old fashioned" hardware store that
> carried very small diameter tubing and strips for hobby use.
>
> ----- Original Message -----
> From: "Bill Ralston" <n7vm at lgcy.com>
> To: <towertalk at contesting.com>
> Cc: <ogden at us.ibm.com>
> Sent: Friday, November 14, 2003 11:24 AM
> Subject: Re: [Towertalk] Connecting grounds to towers
>
>
> > > From: Bill Ogden <ogden at us.ibm.com>
> > >
> > > What is a reasonable way to connect ground wires to a tower (a TX-455,
> in
> > > this case, with the tilt-over feature)?  I plan on three ground rods
and
> > > about 50 radials.  I'll probably use insulated #14 wire (from Home
> Depot)
> > > for the radials and #8 bare for the ground rods.
> >
> > I'd think about using #4 solid Cu or Cu strap - bigger the better.  #4
is
> > avail at Home Depot.
> >
> > I would run three wires from the base or tower leg to the ground rods,
and
> > then run a ring around the base tying all three ground rods together.
> Most
> > folks here seem to thing the cadweld one shots are the way to go, but
I've
> > haven't tried that and have just been using standard ground clamps and
> split
> > bots to make connections.
> >
> > One way to attach the ground lead to the tower is to buy a Polyphaser
> clamp.
> >
> > Another way is to put wrap stainless steel around the tower leg and then
> lay
> > the ground wire against the stainless and hold in down with stainless
> steel
> > hose clamps.  I did this, which gave me about 6" of contact between the
#4
> > ground wire and the tower leg, with the stainless to prevent the
galvanic
> > corrosion.  This is similar to the polyphaser clamp.  The building
> inspector
> > vetoed that, insisting upon an "approved ground clamp"
> >
> > I replaced this with standard ground clamps designed to go on a pipe
(also
> > available at home depot).  As these are made of bronze, there is still a
> > concern about galvanic action, so I placed shims of stainless between
the
> > tower leg and the clamp.  Since the area of contact between the clamp
and
> > the grounding wire is quite small, I used three of these in parallel for
> > ground lead.  The problem is that most building codes / inspectors are
> > really only concerned with DC grounding, and do not understand RF or
> > lightning.
> >
> > Another option might be to find a large enough terminal (again, look in
> the
> > electrical dept at Home Depot) that will go onto the bolt that is
designed
> > to receive a large wire.  Again, be careful about galvanic mismatches.
> You
> > might even machine something out of stainless if you are really
ambitious.
> >
> > >I am surprised about how little mention there is of practical
mechanical
> > >problems in the handbooks.
> >
> > No kidding - I struggled with this for quite some time
> >
> > de Bill N7VM
> >
> >
> > _______________________________________________
> >
> > See: http://www.mscomputer.com  for "Self Supporting Towers", "Wireless
> Weather Stations", and lot's more.  Call Toll Free, 1-800-333-9041 with
any
> questions and ask for Sherman, W2FLA.
> >
> > _______________________________________________
> > TowerTalk mailing list
> > TowerTalk at contesting.com
> > http://lists.contesting.com/mailman/listinfo/towertalk
> >
>
>
> _______________________________________________
>
> See: http://www.mscomputer.com  for "Self Supporting Towers", "Wireless
Weather Stations", and lot's more.  Call Toll Free, 1-800-333-9041 with any
questions and ask for Sherman, W2FLA.
>
> _______________________________________________
> TowerTalk mailing list
> TowerTalk at contesting.com
> http://lists.contesting.com/mailman/listinfo/towertalk
>