150KHz is extremely high for a mechanical oscillator! Bear in mind the number of lifetime open/close cycles specified by the relay manufacturer may be used up in a few seconds at that frequency.
I will warn you that although the circuit does work, it will be extremely unstable, possibly shifting several KHz within the space of a few seconds and the output waveform is just a series of spikes so it's harmonic content will be huge!
A similar technology was used to generate high voltage for powering vacuum tube equipment from 12V before transistors were around. The transformer typically stepped the voltage up to 150V for the HT supply. They were called 'vibrator' units, (not to be confused with other instruments of the same name!) and they were notoriously unreliable. The standard fix when the relay contacts stuck was to hit it with something hard. It was quite common to see power supplies with hammer marks all over them.
If you want to experiment with mechanical radio look at this web reference:
https://en.wikipedia.org/wiki/Varberg_Radio_Station
It would be relatively simple to recreate at home although I would suggest scaling it down a little! I have a DVD video about the transmitter, including 'live' operation scenes during one of it's annual tests.
Brian.