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Re: Sonotube RF Losses



Hi All, 

Been quietly reading everyone's info on the sonotube. I might as well state
that my 12 x 48 secondary is also sonotube. It's named Quik-Tube by the makers
of Quikrete Company. Brown in color and wax coating on the outside. 

I've had good success, but like David, I also run a pig system. Those of us who
do, have a lot of power to get 10 foot bolts easily. It's just a matter of
power and tuning. However, it doesn't surprise me in the least that the
sonotube is lossy as Terry has presented with Q measurments. 

I prepared my sonotube by sanding the outer surface and coating with
polyurathane thinned down allowing it to soak in. After a few days of drying, I
coated the outer with Marine Spar Varish, wound the coil, and added several
coates for a thick and smooth surface. (Never had a static shock problem
either). 

It is apparent to me a higher Q secondary is best accomplished without
sonotube. But it should also be apparent to all of you that sonotubes work just
fine even if there is a loss (look at the number of coilers who have used
sonotubes with great success). Does Q really matter? Well, I think it does with
respects to efficiency, but possibly is small when stepping back and looking at
the big picture. 

One of my goals is to continually develop my coil for efficiency, so even if
the degree of loss is relatively small compared to the big picture, I will
still build my next secondary with a premium former material to provide the
highest Q I can possibly obtain (which is something other than sonotube or
cardboard forms). 

Take care, 
Bart 

Tesla list wrote: 
>
> Original poster: DickHamly-at-aol-dot-com 
>
> I built a 5 foot x 1 foot secondary about 15 years ago on a sonotube.  I 
> wound it and then varnished it heavily.  I used a 15KV 60 ma NST and a simple
>
> static gap.  The primary was wound on a big wooden flowerpot.  It threw 5 
> foot streamers all over the place. 
>
> However, there is obviously a lot of variation in the contents of the fiber 
> and maybe I was lucky. 
>
> Dick Hamly