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Re: A newbie question



Original poster: "Harold Weiss" <hweiss-at-new.rr-dot-com> 

Hi Greg,

Welcome to the list.

The 3.5" pipe is 3" PVC pipe.  The inner diameter is 3" with 1/4" walls for
a outside diameter of 3.5", and should not be hard to find, or try a
plumbing store, also a good source for 1/4" o.d. copper tubing.  With the
PVC pipe the winding length should be 4-5 times the outside diameter or
14-17.5" of which the 18" in your plans is in the ballpark and good to go.
Add 3/4" at the top to leave bare so you can mount the plug to hold your
topload, and add 5" to the bottom to adjust for coupling. (you can always
make it shorter, it's hard to make a short tube longer) As for wire, try #26
as it's a little thicker and easier to work with.  It should also come out
to about 1000 turns. I know Dr. R likes 1400, but I have been able 54" with
a 6" coil with 620 turns of 20 ga.  Being a newbie and not being used to
working around super long streamers, a reasonable, not extreme performance
coil is called for here.

A 6kv 30ma transformer is fine to start, but if you have a variac for it, go
for the 15/60 as you can always throttle it back.  Make sure to use a Terry
filter on it.

   I started with a ceramic version of an MMC cap with bad results.  I then
went to the bottle caps with good results.  You are correct on the
terminals.  Use a 5 gallon bucket and lid.  Once the salt water is in, pour
some mineral oil in each of the bottles and in the bucket. It will stop
condensation /evaporation problems.  One bucket should be .01 uF which
should be enough for a 3" coil. Use more primary turns about 13-15
turns.(rough guesstimate)  A plexi cage is not needed, as you need to be
able to get at the primary to tap it.  Do not use wood/plywood as they can
become conductive.  Plexi works good for primary supports.

May your streamers become long and plentiful!

David E Weiss

 > Hi All,
 >
 > Sorry for making you go all over this again, but I'd appreciate a bit of
help.
 >
 > So, I've read the description and construction notes of George Trinkaus on
 > the TC and I would like to build one too. I went to hardware stores to
look
 > for materials, but even to find pipes for the primary and secondary would
 > be a problem. George in his description goes with a 3.5" x 18" secondary
 > and a 7" x 5.75" primary. And this is what I can't find.
 > So I thought I might reduce the sec. and the prim. to one half.
 >
 > 1. In this case, would the #28 wire be adequat for the task or should I
 > look for a thinner? Same question  for the primary's #8 stranded wire.
 >
 > 2. Transformer-wise, the booklet suggests something between 6000 and 15000
 > V and 30 to 60 mA. I guess the transformer at the lower end would be
 > sufficient.
 >
 > 3. The other hardnut is the capacitor (as everywhere else). I found the
 > description of the beer-bottle capacitor in George's booklet and I think
 > it'd be OK to build it. There is just one thing which is not clear. So
when
 > bottles are filled up and are in the "dishpan" and its filled up too to
 > within about 0.25" of the top, do you have to seal the "dishpan"?
Otherwise
 > if I got it right, the interconnected bottle terminals is one pole and the
 > metal inside of the "dishpan" is the other.   OR  Would you rather suggest
 > to buy the capacitor? Since it wouldn't be a big TC I am sure that I won't
 > need a 0.3uF 35Kv capacitor. How can I figure out what I need?
 >
 > 4. Since I could get hold of as many plexiglas as I can, I tought I would
 > build a cage around the primary circuit for the sake of security. BUT
would
 > plexiglas securize anything at all at these high voltages? Is wood any
 > better? And wouldn't heat evacuation be a problem? First I thought to put
 > everything but the coils under the cage but maybe spark gap should be left
 > in the open air so it can be cooled easily.
 >
 > I know I got many things to learn but I am 100% motivated and I know I can
 > do it. Of course security is very important, so if there are some other
 > things I should know about (and what is not at pupman-dot-com on the safety
 > sheet) please tell me.
 >
 > If you didn't get tired of my questions and could read it until here, I'd
 > be really happy to read your answers.
 > Thanks you very much.
 >
 > Greg
 > a humble newbie
 >
 >