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.
----- Original Message -----
From: "Jack Brindle" <email@example.com>
To: "Paul Christensen" <firstname.lastname@example.org>
Sent: Friday, February 10, 2012 10:46 AM
Subject: Re: [TowerTalk] ground plates (was DXE Patents)
> Strain relief. If the radials are firmly attached to the solder lugs
> then there is little likelihood that they will separate from the plate
> if pulled on, kicked, etc. My radials are up about 10 feet in the air
> - I have them not just crimped, but the wires go through the crimp
> connection and form a loop around the screw head before passing back
> through the crimp. They simply do not pull out.
> If the bus bars are used, the wires tend to pull out rather easily, no
> matter how tight the screw is. I also note that the bus bars are
> generally aluminum, so we still have the problem with copper (wires)
> and aluminum contacts...
> Jack Brindle, W6FB
> On Feb 10, 2012, at 9:36 AM, Paul Christensen wrote:
>>> I've never understood why people don't just use extension buss
>>> bars ...
>>> like the kind that you can buy from Home Depot for adding more
>>> ground or
>>> neutral connections to your electric service entrance panel.
>> Good point, especially if single-point connections are used. I
>> brought up
>> the example of using 2-hole lugs as being a better plate
>> alternative, but if
>> I were to create a radial field tomorrow, I would probably just make a
>> square ring around the base using standard copper pipe, and use
>> silver-solder together with an acetylene torch (not with oxygen --
>> way too
>> hot) at the 90 degree elbows. Radials are then soldered direct to
>> the pipe.
>> Another 'cheap and good' alternative to a radial plate is to make a
>> ring bus
>> out of 1/0 copper wire. This requires stripping the insulation, but
>> the radials are soldered direct to the ring.
>> In both examples, long-term conductivity will almost certainly be
>> than any radial plate solution.
>> Paul, W9AC
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