OK PC5-52 fitted reception was OK and now isn't, Why?

I am using a Blaupunkt DAB 54 head unit with a window mounted DAB aerial fitted and a PC5-52 fitted to power the amp in the original analogue aerial. It seemed to work and the signal level was near max, but I have been listening to DAB for most of the time. A couple of weeks back I tried to listen to FM again because I went to France and I didn't think my DAB aerial was of the correct band, FM reception seemed bad, lower level and hissy even back in the UK. I have replaced the PC5-52 thinking that was faulty but it wasn't. What else could be the problem? The aerial base amp? A short? I have not moved the original aerial cable or touched the base.

Thanks for any help.