yeah i'm actually in the kHz range, my frequency generator is set to 0..200kHz in 500Hz steps.
gave the tank circuit another look, unfortunately my supply voltage doesn't double. will have to see what the problem is.
the transformer is really strange, instead of giving out round squares when fed with 50% square waves (picture on tech brief page 81) it's creating the sinus wave, which i can't use really. and the voltage isn't stepped up by factor 19 - didn't really expect it with squares - but only with the factor 2/3 if that at all.
when not using the transformer at all i can see the discharge pattern of the cap nicely, like on jnaudins page.
won't have time till tuesday or wednesday, will make an update then.