The New, Neat Tube Coil.

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Original poster: "Sundog by way of Terry Fritz <twftesla-at-qwest-dot-net>" <sundog-at-timeship-dot-net>

    Hi All, 
 
  Well, I re-built my toob coil, running a single 833A (out of 4), and I have
to say that a cleaner, neater setup really makes a big difference. As does good
quality solder joints and whatnot.   Currently I'm still having a bit of
trouble with my tuning and grid leak resistor.  Tuning is picky, to say the
least, and the grid leak R has always been a pain in the butt.  I broke down
and bought some high powered resistors to put into a block and use, but for now
I'm using sparkplug wire and a SW resistor. Works good, just a little smoke ;) 

 
 The tube coil is running *much!* better now!  My primary's inductance is too
low to effectively tune with the small capacitance I want to run, so I wound
some 3" PVC with 14ga THHN, ~50 turns.  I ended up adding another MMC string so
I'm right around 1nf on the tank cap, and it tunes out great.  My MOT lacks the
grunt to reliably charge the 5-6nf tank cap it wants without the output
suffering (more of a choppy 60hz sound than the smooth buzz I get from a tiny
tank cap).   Coupling could be tighter, but it works pretty good as it is. 
 
     Later on this weekend, I'll throw in my variable SW cap and report on how
well it does.  As the coil sits now, I got white-orange sparks to the air, a
good 8-10" long.  And I re-discovered why tube coils irritate me.  Those
!!$#%&*($#^!  RF burns!!!!  I collected about a million of 'em from everything
in the garage. Ahwell, at least the tube coil is pretty to watch :)    
 
                                                                           
                    Laters!   Shad