B737-500
Communication Breakdown
ATC Issue All Types; Deviation / Discrepancy - Procedural Published Material / Policy
General None Reported / Taken
ATC Equipment / Nav Facility / Buildings
Working Sector 30 with Sector 23; 87 and the North half of 97 combined; which is normal for that time of night. There was a solid line of weather to the West which had been impacting us all day; especially with bad rides. While working; I became aware that I could not hear many aircraft transmitting on 124.45 (CMH frequency.) This was a problem I ran into before in the last several weeks before and Maintenance was/is aware of it. It has been an on-going problem for a while which hasn't been successfully remedied. I called the OMIC desk twice; but he was running between several different areas dealing with the issues the weather was causing; including holding. I finally ran over to the SOC and asked them to send someone who could help with a frequency issue. When he arrived I was quite busy and did my best to explain the problem while dealing with the frequency issues; other traffic issues I had working; chop and weather. I was doing my best to comply with the Maintenance persons' requests and having aircraft test frequency configurations. In normal operation we have to turn off one of the sites because the frequency is almost unreadable with both turned on. While this was happening; I gave enroute descents to several aircraft descending. I realized too late that they were not going to have the 5 miles necessary. While I am fully responsible for distractions; I did and was. The Maintenance person was very quiet while I was talking and only responded or made a request when I initiated conversation. I don't blame the frequency problems or distractions for missing the traffic; I do however firmly believe that had 124.45 been working correctly I would not have had my attention divided and missed the traffic. Fix the mess on 124.45. We used to have one transmitter that was high powered and worked beautifully for decades. They lowered the power and installed a second transmitter and told us it would work just as well; it does not.
ZID Controller described a conflict event when frequency problems with 124.45 caused a distraction resulting in the event. The reporter noted the frequency issue must be fixed.