Hi all,
I want to add a bit here on this post since this has come up somewhere
else. Because likely to come up here also. Has to do with this SGTC, which
is the only one we have that is a SG type, that I am using to demonstrate
the Staccato on.
Part of my response:
As I mentioned in my post further up, I accepted these losses you mentioned
here.
I will give some more background rambling on how this came about here for
now. I will admit, I had a feeling this would come up :^)
When I was somewhat modifying this original vertical helix primary
(practically no one does a vertical helix primary anymore for several good
reasons on a SGTC), I knew I was going to possiblity push some limits on
this tighter coupling. And this got even tighter switching to copper
tubing. But I wanted to cut some losses of the original primary wire, which
was suggested by the original plans we had in the very early 1980's. This
was a type of Belden very heavy red rubber insulated small 14 Guage high
voltage wire, kind of like NST wire. I would say very lossy stuff now,
rubber not looking so great anymore, so decided to switch to copper tubing.
Well, copper tubing made this vertical helix even taller further increasing
coupling. But I wanted to keep this old school vertical helix for some
nostalgia of original build of this coil. From some calculations,
inductance available is going to be close for having enough. Did not want
to go any taller at all for fear of arcs to secondary. Did not want to
modify new secondary PVC screw on mount to possibly raise height up some. I
am tapped using full inductance of the primary for this running coil. Need
it all and some more...so hence some more reasons why I did this.
I did say figured this extra inductance because I needed it. Now I
explored in my head to keep my original short proper connections and just
put on close by a big roller inductor I have to get it tuned. But again
losses itself...and I will admit I would be tempted to change this while
running putting me in harm's way of being struck. Thoughts of long
extended adjuster handle maybe...nah... decided this is crazy. I will just
do the very simple long leads for now and get this old fella just running
again finally. Has not been run since oh....1989 and accept these losses
for now.
I think we all run into problems and design compromises at times.
Also this coil does need a bigger toroid. Despite break out point, as seen
in video here, multiple streamers still coming out at times.
I actually do have future plan for this coil and to correct this problem
and probably the best way to do this. I did mention that this secondary was
built old school on cardboard tube and varnish back then, well I am sure
this is lossy itself and even more now being old. Also there are now
"crystals" growing on the varnish inside and outside. Wipe off real easy,
but they constantly grow. The days are getting numbered on this fella. So a
completely new secondary is a future project. I am going to raise the
frequency some, solving my inductance primary problem, while figuring in
some adjustment wiggle room.
More than one way to fix some problems...
Chris Reeland
Ladd Illinois USA
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