Radio loses tuning ability and just hisses

[MalcolmSawyer]

Our '03 A4 2.5TDI Cabriolet has suddenly developed a problem with the radio.... it stops tuning into any station and the display changes to show the frequency, all presets do not work and the "Comfort" tuning facility just moves the frequency manually by tenths. (FM and AM have the same problem). The sound is just a hiss except if you manually tune into a strong signal like Radio2 you get a signal of sorts. It's as if you have no aerial. Meanwhile the CD player and tape works fine. Sometimes, first thing, the radio will work for a short time, but once warmed up it stops.
Any ideas of possible faults and repair routes much appreciated. Thanks

[cabrio-newbie]

I have what appears to be exactly the same symptoms with my '03 A4 cabriolet, radio occasionally works as normal, sometimes only picks up local radio and other times not at all. Am suspecting a faulty aerial lead. Other threads have identified lead breaking as it enters the boot lid.