Re: Need Help with 15 degree Primary Support System
In a message dated 7/17/99 3:06:35 AM Pacific Daylight Time, tesla-at-pupman-dot-com
- snip -
> However, I have noted that on all coils over 8" that the primary is
> always flat.
> Is the idea of an inclined primary outdated? Is it better to go with
> a flat versus an inclined primary on all coil sizes? I suspect this
> might be a small controversy given the amount of coilers using an
> inclined primary already. The question is, how much much will I
> have to raise the secondary to promote tighter coupling with a
> flat primary? Weaver's tests seemed to me to be pretty conclusive.
> I agree that it's much easier to build a flat primary. The 15 degree
> was giving me grief for trying to figure out how to keep the tubing
> _down_ in the slots. I was just about to ditch wood and go plastic
> since I could have routed the slots down deeper to hold the tubing
> better. I am aware that Gary Lau used Lexan for his support system
> and I did consider that but wanted to try wood first. I am also aware
> of a Brit that used HDPE cutting boards cut into strips for his flat
> primary at http://www.breakfix.demon.co.uk/tesla_primary.html and
> it really looks good.
> I also read your archived article on building a toroid and chose to
> go with a 3" PVC end cap since I want to try different size toploads.
> I ended up using flexible aluminum foil ducting with the two inverted
> pie pans as the center hub to get a 21x6 toroid. It works great!
I am convinced that the coupling can be adjusted from too loose to too tight
when using a flat primary with most coil designs. Both my 6.0" and my 3.0"
coils use flat primaries with the first turn of the secondary set just about
even with the flat primary windings. When I was using the inclined primary
on the 6.0" coil, I had to raise the secondary up about 2.0" to prevent
overcoupling. On the other hand, using a slightly inclinded primary makes it
easier to get the tap lead under the primary if you don't have cutouts in the
base for direct access from the bottom.
BTW, compared to an inclined primary, with a flat primary you will have to
lower the secondary (or raise the primary) to promote tighter coupling.