Kenwood r 5000 no FM reception
 

Hi ,I m a newbie, and I wonder if any of you guys could help me. I just got a Kenwood r 5000 with a VC 20 VHF and have it hooked to an Ameco preamplifier/active antenna.It works fine in all frequencies but FM 87.5-108 MHz; I also have noticed that the best reception I get in all other frequencies is when I have it on the AM mode,except FM of course where I only get static.
Thanks in advance for any help.I have read the manual and still can't figure out if there is something wrong with the radio or I'm not operating it properly.