This is almost legal I have improved the antenna on this particular mini FM sender slightly, but only so I could get the signal across the whole of the site at work, otherwise it is cut across by the digital TV boxes the old folk use in their rooms. This old radio is usually kept in the maintenance shed. It is probably older than DJ Massie (and a few other folk on here). I had to use 87.8 as the frequency (I leave 87.5 clear so as not to interfere with a pirate which seems to occasionally operate there, just enough space before BBC Manningtree.
I couldn’t use the other end of the band, as the radio only tunes up to 104 MHz! As it appears to be a Europe wide model, maybe that bit was allocated to public service communications radios in other countries than the UK.
There is some GSM interference from my mobile (as I was out in the sticks on the edge of the reception area).