Brett Miller -- 6 Inch Coil Stats: ----------------------------------------------------------------- SECONDARY COIL Coil Form - 6 inch green Drain Flume PVC Diameter - 6.25" Winding Length - 24" Wire Gauge - Awg 23 Number of Turns - 1031 Secondary Resonant Frequency - 149 KHz Secondary Inductance - 38.7mH = 38721uH Secondary Self Capacitance - 10.9pf Coupling Coefficient - 0.1945 Toroid Capacitance - 18.7pf Secondary Cself - 10.9pf --------------------------- C total - 29.5pf PRIMARY COIL Number of Turns - 14 0.25" copper tubing 0.25" spacing between turns 30 degree saucer configuration Primary Inductance - 92.48uH Primary Resonant Frequency - 148KHz w/MMC PRIMARY CAP (MMC) 2 strings of 9 0.056uf 1600v Panasonic foil/poly caps in series for a total of 0.0124uf at 14400 volts. 10meg ohm 1/2 watt Yaego Carbon Film resistors were placed across each cap to bleed off excess charge. SPARK GAP Standard TCBOR with up to 6 gaps available. When the total gap spacing is measured I will make that information available. I should say that I do run the gaps extremely wide. The cap probably rings up to 25000 volts or somewhere in that range. So far I haven't lost an NST yet in over a year of firing this coil with a wide static gap. POWER SUPPLY 1 unmodefied France 12/60 NST, powered through a 0-140 volt General Radio 20 amp variac. RF GROUND One 1.5" dia copper pipe about 3 feet long, pounded all the way in the ground, about 12 feet from the coil. TOPLOAD 4" x 17" Dryer duct. Directly underneath the duct toroid I use an ACR (Anti Corona Ring) made of a foam "Fun Noodle" wrapped around a foam disk and covered with aluminum tape. The dimensions of this ACR are 11.75" x 2.75". To date I have had no strikes to the primary despite the 30 degree incline and lack of a strike ring. MAXIMUM ARC LENGTH TO DATE 45 inches. 1.7 x SQRT(720) = 45.615785 Usually arcs are around 30-36 inches, but when I run all the gaps I can get 45" streamers and an occational power arc to ground of that length.