What are the disadvantages of the OLTC compared to a spark-gap coil?
It’s harder to achieve high energies, so the sparks are not quite as long for a given power input. (The best OLTC performance to date is 13″ sparks for 300 watts input.) IGBTs are easier to wreck than spark gaps. A small OLTC might not do anything without a breakout point. Finally, the OLTC has complex electronics in it. The complexity is similar to an SSTC.
