[Spooks] Whats this please

[Mike]

Hi

http://mysite.wanadoo-members.co.uk/thesecretsiteofmike/18000khz.mp3

While waiting for E15 to show up I found that 18000 was jammed by this odd
signal, sounds like a very bubbly tummy :-)
Its just a short mp3 file 67kb so if anyone would like to have a listen and
let me know what it is please?

The beeps you hear in the clip are from my radio as I switch between USB
and LSB then into AM.
It did seem to be a AM signal?