The big bad Mark III

["Troy Peterson" <highvoltage-at-mad.scientist-dot-com> (by way of Terry Fritz <twftesla-at-uswest-dot-net>)]

 Dan,

 >  <-Snip->
 > (6"), 23 awg magnet wire and i am going to order some mmc caps(2000vdc
 .068
 > uf each--for a total of capacitance of .03 uf) through the current bulk
 buy
 > here on the list.
 Where can I get more information on this builk buy, it just may be my
 ticket.

 > i think i am going to use .25" tubing (flat spiral or maybe a 15 degree
 > conical) for the primary. when i have more time (i am in college now) i
 will

 I tried a 15 degree conical on my last coil, but I couldn't tune it. I
 rarranged the primary form and converted it into a flat spriral and it
 worked MUCH better.

 > try the flat ribbon conductor primary you mentioned. one cheap
alternative
 > would be using aluminum roof flashing. the problem is cutting down the
 width
 > to a workable size. an expensive solution would be going to a machine
shop
 > and have them cut you a piece. you could also try flattening tubing out
 with
 > a hammer or use some heavy duty rollers (know anyone that has a steam
 > roller?!) flat conductors should afford lowered RF resistance (though
some
 > coilers on this list are bound dissagree) as well as being compact as you
 > mentioned. i had never thought about the corona problems...just use some
 > fine grit sand paper to smooth the rough edges and see what happens.

 I had a lot of trouble making my last primary using 1/4" tubing. It looked
 sooooo easy..... I ended up with very uneven spacing, and creases in the
 pipe. The main reason I think was that I didn't have a well shaped form (I
 didn't have access to a band saw) so I just formed the spiral and used
 plastic cable ties to attach it to wooden radials.

 > what have you planned for spark gap?

 I am not elaborate enough for a rotary gap yet, esp. since I will be
running
 this coil off of a 15 amp 120 circuit. I think if a suitable motor would
 even run off of 120 it would probably put me overbudget on amps. I will
 probably start with the RQ gap from my last coil, then build a better one
 when I have the time. The RQ gap I have is not well built, but it does the
 job. The main problem I think is that the pipe lengths are only 1", thats
 not alot of surface area for heat sinking. The gap is in a 4" pvc pipe and
 cooled by a muffin fan.
 Thaks for your reply Dan,

 Regards,
 Troy Peterson [VE7SOK]
 troypete-at-sunwave-dot-net
 highvoltage-at-mad.scientist-dot-com





>
>
>
>
>