You can find them listed under the Federal agencies under the State of Ohio in the database.
http://www.radioreference.com/modules.php?name=RR&aid=3537
For brevity's sake:
Main Cincinnati FBI repeater is:
173.100 ----- FBI DVP Cincinnati A1 162.7375 in
The others are:
173.125 ---- FBI DVP Covington KY ?
173.150 ---- FBI DVP Cincinnati A2 162.7625 in
173.175 ---- FBI DVP Dayton 167.4875 in
What you will mainly hear is a high pitch tone, then "whoosh", as
nearly 99% of the traffic is DVP (Encrypted). On rare occasions you may catch something "in the clear".
Do not expect it to produce much interesting listening.