what type of connector is at the end? i suspect it is large and used for CB.
http://www.toolfetch.com/roadpro-rp-9cc-9-cb-antenna-coax-cable-with-pl-259-connectors-black.html?utm_source=google&utm_medium=cse&utm_term=DAS-RP-9CC&gclid=Cj0KEQjwpvufBRCwzp_zyqfkhrcBEiQA8b-SHEeDvqq9Xu1kRKrdT9vZe1fPuHZTfsdWlYdGBLIeBsQaAvhO8P8HAQ
for it to be for FM the connector would be small to fit into the back of the radio.