Re: Static Gap Spacing

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

Original poster: "Jim Lux by way of Terry Fritz <twftesla-at-qwest-dot-net>" <jimlux-at-earthlink-dot-net>

> > Hi,
> >  I'm making a static gap out of 12 3" peices of 1" copper pipe all
screwd
> > into
> >  lexon/lucite
>
> Hi Erik,
>
> I assume you are going to lay the copper tubes down flat on the plastic.
> Uh uh. The plastic will melt, or at least get mushy. I have a copper tube
gap
>
> but the tubes are on G-10 and fastened with 8-32 screws and lock washers.
If
> all you do is lay the tubes down flat and screw them in place, you won't
be
> able to adjust the gap.
> Another variation is a sandwiched stagger gap where the spacing is
adjusted
> by varying the distance between the two layers of tubing. This is
basically
> the Scott D gap. Probably my best static gap is made from 5 one-inch
copper
> pipe couplings. These are mounted vertically on five 8-32 brass screws
around
> 4 inches long, carefully lined up on a piece of G-10. Use hex nuts and
pieces
> of brass for shelves to hold the couplings around an inch above the G-10
slab.
> I put the couplings in a vise to carefully "ovalize" them. Gap spacing is
> easily adjusted simply by rotating the couplings to bring them closer or
> farther apart.

Another approach is to mount the pieces of pipe with a single pivot in the
center of the side.  If you change the angles of all of them, you can change
the gap. (think of a venetian blind...)

>
> I had best not comment on your gap spacing as I don't have that much
> experience.  Twelve pieces sounds like at least double what it should be.
> Much too lossy.
> In a multigap, the total spacing is the sum of the indvidual gaps. I would
> start out
> with  something totalling around 0.20 nches and increase the gap from
there.
>
> Happy day,
> Ralph Zekelman
>
>
>