Re: primary mounting positions

[Parpp807-at-aol-dot-com (by way of Terry Fritz <twftesla-at-uswest-dot-net>)]

In a message dated 7/4/00 2:15:21 PM Central Daylight Time, 
twftesla-at-uswest-dot-net writes:

<< You may want to try a true 1/2 wave coil where the two ends are terminals
 and the center is basically grounded.  If you try this, be sure and let us
 all know what happens!  The third item above could be really interesting!
 Cheers,
Terry<<

Hi,
This sounds very much like my 1/2-wave bipolar. The secondary is 1460 turns of
#28 SE wound on 21 inches of 3.5 inch OD PVC. Other than sanding, I made no 
special preparation of the PVC. PVC end caps are used. I applied many coats 
of polyu to get a nice glasslike finish. I wrapped the coil in vinyl tape and 
wrapped two layers of 1/32 silicone rubber sheet around the whole thing. The 
primary is five turns
of 3/16 Cu tubing spaced to 3/8 inch and an 8 inch diameter. The primary is 
centered
on the secondary which is then at an effective ground potential. The cap is a 
0.024
MMC. I have a parallel combo of 15/90 NSTs for an input power of 1350 W. 
There is no arcing between the primary and secondary. I have two "rabbit-ear"
antennae connected to terminals at the ends of the coil exactly 21 inches 
apart.
With the two rabbit ears spaced the maximum 21 inches I get a full 21 inches 
of
spark between the ears, lots of corona and streamers. At 21 inches this is 
the maximum voltage across the 1/2-wave coil and I have exceeded the 
insulation
capabilities of the wooden frame. I get a 12 inch arc down the side of one of 
the coil supports. This arc is headed for a nail!! :-)) Project for this 
winter is to
double the spark length.

Happy day,
Ralph Zekelman