At 05:42 PM 7/12/2006, K4SAV wrote:
> > Strap width Inductance uH
> > 0.5 in 0.40
> > 1 in 0.36
>
>
>Given that a 0.5 inch wide strap is about the same as a wire.. what
>about multiple wires in parallel.. If they are spaced apart far enough,
>the inductances will be parallel.
>
>--------------------------
>
>Good thought, but this might be hard to implement at the bonding point
>if you are thinking of a ground rod/radial system. If you space two #4
>wires 6 inches apart you can get 0.72 times the inductance of a single
>wire. If you space the wires 3.3 ft apart you can get 0.6 times the
>inductance of a single wire.
Hmm.. but, if I had four AWG 10 wires laying side by side, that's like a
0.4 inch wide by 0.1 inch high strap... i.e. the L should be 0.40 uH (give
or take) for the 10 foot run. I suspect that 4 AWG16 (roughly 0.05"
diameter) wires spanning half an inch would have about the same inductance,
and 4 AWG16s is a lot cheaper than a single AWG4, or, perhaps, an 0.05x0.5"
strip. As you show in your table, (and you mention above) you have to
spread over a MUCH wider distance to materially reduce the L.
Where I'm going with this is that there might be some very convenient, and
inexpensive, ways to get a fairly low inductance connection comparable to
AWG4, and potentially easier to handle. For instance, there's AWG16 ribbon
cable that shows up surplus every once in a while. Or, perhaps, if there's
a "deal" on cheap extension cords. If DC resistance isn't the issue, you
don't really need the copper mass of a big solid chunk. Something with
fairly small copper strands separated by plastic, paper, other fillers, can
have an impedance for RF and/or lightning that's pretty acceptable. Think
of it as quasi Litz wire.
>Interesting link on "quarter shrinking".
Yes.. it's a fascinating process. I imagine one could use it to crimp
connectors onto ground rods, with great expense and complexity (and massive
overkill.. like fishing with a "DuPont lure"). Certainly one can smoothly
crush 3/4" copper pipe to about 1/4" OD.
>Jerry, K4SAV
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