555 timer FM transmitter
The original article states


  The carrier frequency is set using the 5 kΩ potentiometer behaving as a potential divider with one end at Vcc and the other at ground. The frequency of the free running oscillator is set to approximately 455.50 kHz.


This is not in the FM radio band which extends from about 88 to 108 MHz so you will not be able to pick this up on your radio - unless you somehow manage to generate the right harmonics.

The preceding paragraph says 


  Here is a frequency modulation (FM) circuit that uses a 555 timer in astable mode to generate a sine wave carrier. GCSE students might find it interesting as they are often playing with the 555 timer IC.


GCSE is a UK second level school standard so I suspect that this might be part of a course studying basic electronics and that a matching receiver would be required.