Sn/Pb solder doesn't last long in contact with most soils, either.
The way I've seen AM broadcast radial systems done, which have a design life of
30 years, is to use #4 Cu wire for the radials brazed to a copper ring. Brazing
will last at least as long as the Cu.
Al
AB2ZY
-----Original Message-----
From: towertalk-bounces@contesting.com
[mailto:towertalk-bounces@contesting.com] On Behalf Of N2TK, Tony
Sent: Friday, February 10, 2012 5:29 PM
To: towertalk@contesting.com
Subject: Re: [TowerTalk] ground plates (was DXE Patents)
Has anyone used these buss bars on the soil for at least a few years to check
for corrosion? Here in upstate NY, copper holds up somewhat well with direct
soli contact. But our soil will totally remove exposed aluminum (bare 70 ohm
CATV cable) within 5 years if in contact with the ground.
N2TK, Tony
-----Original Message-----
From: towertalk-bounces@contesting.com
[mailto:towertalk-bounces@contesting.com] On Behalf Of David Gilbert
Sent: Friday, February 10, 2012 1:30 PM
To: towertalk@contesting.com
Subject: Re: [TowerTalk] ground plates (was DXE Patents)
The regular Home Depot buss extension bars are designed for both copper and
aluminum wires so I don't think that's a problem anyway, but I have a couple of
extra bars on hand so I'll put some short pieces of wire in them and bury them
in moist soil (one in mostly acidic potting soil and the other in mostly
alkaline Arizona desert soil) as a test. I'll report back here every so often
on the results.
73,
Dave AB7E
On 2/10/2012 11:00 AM, EZ wrote:
> Copper to aluminum buss bar mismatch can be handled by using anit
> oxidant grease on the connection point. I thought that the
> dis-similar metal problem is only a problem with the introduction of
> moisture; so if it is greased and kept dry it's a moot issue. (Maybe
someone can confirm this).
> I've used some automotive rubberized undercoating on outdoor and
> buried connections and it's worked well for totally sealing up these
> kind of connections. It's a thick sticky black tar like goop that you
> spray out a can. Good stuff!
>
> Also the copper buss bars, although available, are expensive! I
> priced one with 14 holes, 6.7" long, and it was $24.70. If you need
> enough for 60 radials...well, you can do the math.
>
> Chris
> KF7P
>
>
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