?? if you need high DC voltage use https://en.wikipedia.org/wiki/Voltage_multiplier -- the lower frequencies require bigger capacitors

I was going to use a multiplier at the transformer output to get even higher voltage.

 

I want to experiment with a spark gap and the frequencies it generates. I don't have a neon transformer so that is why I need the oscillator. And I don't have sufficient knowledge in electronics because that is not what I am studying, it's just a hobby.

I was going to use a multiplier at the transformer output to get even higher voltage.

If that's what you're trying to do, be advised that a 555 chip all by itself can't deliver anything near the amount of power required to generate those voltages, no matter what step-up transformer you use or what voltage multiplier scheme. Once again: read the data sheet for the 555; it will tell you how much current the 555's output can deliver. Hint: it's pretty small.

No disrespect intended, but at this stage I don't think you should be playing around with the kind of voltages produced by a neon transformer, no matter how you intend to produce those voltages. This is dangerous stuff, and potentially lethal. I'd suggest you learn a LOT more about electronics before tackling something like this.

 

I was going to use a multiplier at the transformer output to get even higher voltage.

https://en.wikipedia.org/wiki/Electrical_breakdown
https://en.wikipedia.org/wiki/Dielectric_strength
seems you need over 3kV for spark radio

. . . i managed 650V( 477µC micro-coulombs)(to 3x in series 2.2uF(400V) → 733nF(1.2kV) capacitor) from 3V(2xAA) with pulse transformer and 10x 100nF(400V) 1N4007(1A,700V) voltage multiplier - and i managed to touch the wrong parts of the grid /!\ more than couple of times /!\ - i don't consider myself an idiot but it only takes a fragment of a second to not actively compute/follow your position and applied potential in a high voltage circuit !!!

it takes a fine tuning to get these circuits going - the fine tuning usually differs a lot of the simulation results ... the attached pdf has 65% efficiency gained in Simulation -- while -- with 400V transistors in real life circuit i managed 73% @ some 370µA through a chain of LED-s - e.g - 10x LED-s 173V×370µA÷73%→2V×43mA to sawthooth = max. or peak 86mA ← from dt·I.avg=(dt·I.pk)÷2 -- just about you don't have to start to deal with cooling yet (e.g. if your MOSFET-s won' t burn -- your inductros or High frequency Pulse-TF will -- it's a lot of headace to invent a bike here -- it's easier to buy your setup . . .)