Derby Teslathon 2004

___The UK Teslathon has been going since 1998. This year's was as good as ever, if not better. A big thanks to Martin Dale for organising it, and the Derby and District Amateur Radio Society www.dadars.org.uk for hosting it.

___Martin Dale unleashed this monstrous machine which he had just finished building the previous night. The power source was an 11kV, 5kVA pole pig, with an async rotary gap, and some MMC caps and a ballast choke borrowed from Richie Burnett. It shot out massive white-hot arcs which hit the ceiling several times (a distance of 6ft 8ins) and made an ear-splitting racket. Excellent!

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___Phil Parry rebuilt his vacuum tube coil for the day, now using a 572B tube powered by a microwave oven transformer. Here he is demonstrating the health-giving powers of RF current. "A zapping a day keeps the doctor away." Or something like that?

___Derek Woodroffe brought a huge variety of very unusual and innovative coils, including Nano Tess, the smallest SSTC ever made, and Millie Tess, a tiny coil based on a ham radio transmitter design, which runs off a not-so-tiny pack of 56 AA batteries. Derek also demonstrated the AD-OLTC, which spat streamers over 20" while sounding like something off the Forbidden Planet soundtrack. Unfortunately the AD was a victim of its own success- as soon as it started getting good output, it struck its own primary and self-destructed.

___<--- Hence, Derek spent most of the day doing this

___www.extremeelectronics.co.uk

___About three days before the event, Mike Harrison suddenly decided to build a second Marx generator tower. He went into construction overdrive and disappeared under a mound of plexiglass swarf. Amazingly, it was ready on time, and before the day was out he had both towers connected together and triggering properly, and at last achieved his goal of creating a 1,000,000 volt discharge. Way to go, Mike!
___Unfortunately, Mike's enormous sparks also created a sizable EMP event which blew up the power supply in his laptop. But he'll probably have it fixed in about 10 minutes.

___www.electricstuff.co.uk

___Adam Horden brought this finely crafted and neat looking "AH-OLTC". But he warned us that he had been having trouble getting it to perform. Everyone gathered round, prodded it with scope probes and soldering irons, and WILLED IT TO WORK... he eventually got about 6" from it. But OLTCing is a new branch of the hobby and we're still not sure quite how the pesky things work.

___www.acidtech.net

___Steve Conner (ie me) trekked all the way down from Glasgow with the OLTC II. This freakish hybrid uses a 14uF @ 1kV tank capacitor, a single turn primary, and two 1200V 600A industrial IGBT transistors where a normal TC's spark gap would be. Like all OLTCs, it runs directly off 240V mains with no HV step-up transformer.
___It performed pretty well, and with an extra toroid and another 4uF of capacitors, it gave strikes to 6ft 1in. Unfortunately, the solid-state world record is 7ft 9ins more than 10ft. Where's Igor when you need him!

___www.scopeboy.com/tesla/

___Steve also brought the Dirty Weekend SSTC. This was an experimental mini SSTC built in a weekend, and powered by a H-bridge of IRFP460 MOSFETs with a phase locked loop driver. As the name suggests it is a horrible tangled mess of wires with a primary wound on a plant pot.
___It gave arcs about 10" long and performed reliably, until he somehow managed to connect it up backwards and blow the FETs to smush.

___James Pawson showed up with his two SSTCs, the "Stubby" and the JP-SSTC. The stubby performed well, but the JP was not a happy bunny: it kept blowing MOSFETs. Power electronics is a black art.

___thedatastream.4hv.org

___Solid-state coiling must be taking off. We blew enough devices on the day to make a "silicon cemetery".
___600A IGBT brick from Finn Hammer's OLTC, 110A IGBT mini-blocks from Colin Heath's ISSTC, 48A MOSFET mini-blocks from JP-SSTC, fuses and two TO-247 IGBTs from AD-OLTC, two TO-220 mosfets from "Stubby".

___Colin Heath's ISSTC. On Friday evening, it picked up so much RF from Martin's big coil that it exploded. It then spent the whole of Saturday in pieces being cursed at.

___Finn Hammer came all the way from Denmark with this ingeniously constructed OLTC. Unfortunately, something went wrong with the driver circuit, and his 600A IGBT brick went boom.

___Hammer's Tesla Pages

___Last but not least... Mark Hales brought his collection of violet ray machines (none of which are getting anywhere ME!!) and a big box of novelty neon bulbs (see pic) which he imported from the states.

• Paul Fryer's coil that he got working after we had packed up
  
• Sparks from Finn's OLTC
• Sparks from Adam's OLTC
• Sparks from Colin's ISSTC
• Colin's ISSTC NOT in pieces (it's cleverly built into an old bedside cabinet)
• Phil Parry NOT passing RF current through his body

___Pictures by Adam Horden, James Pawson, and Mike Harrison.

___Words by Steve Conner
(steve at scopeboy dot com)