Date: 202106
Local time of day: 1201-1800
Location: ZZZ.ARTCC, US
Flight conditions: VMC
Light: Daylight
Aircraft: Skylane 182/RG Turbo Skylane/RG
Operator: Personal
Operating under: Part 91
Flight plan: VFR
Mission: Personal
Flight phase: Cruise
Airspace: Class E ZZZ
ATC / advisory: Center ZZZ
Second aircraft: Any Unknown or Unlisted Aircraft Manufacturer
Aircraft component: Transponder
Component problem: Malfunctioning
Reporter organization: Government
Reporter function: Enroute
Human factors: Confusion; Distraction; Workload; Time Pressure; Situational Awareness; Human-Machine Interface
Anomaly: ATC Issue All Types; Conflict Airborne Conflict; Inflight Event / Encounter CFTT / CFIT
When detected: In-flight
Result: Air Traffic Control Issued New Clearance; Air Traffic Control Separated Traffic
Contributing factors: Procedure; Human Factors; Airspace Structure; Aircraft
Primary problem: Procedure

Narrative: I was working the combined sectors as R-Side (Radar Controller). About the time Aircraft X called requesting flight following while he conducted a practice approach to ZZZ; ZZZ1 Tower called for a release on Aircraft Y. My D-Side (Handoff/Assist Controller) released Aircraft Y heading 270 climbing 4;000 feet while Aircraft X was still southbound approx 3;700 to 3;800 feet. I cannot get the replay to work properly so based on my fuzzy memory I remember multiple aircraft calling airborne for clearances and flight following as Aircraft Y called airborne off of ZZZ1. Two of the other aircraft were calling up. Aircraft Y checked on noting the transponder code he had selected. It was interesting because I did not see a transponder code; only a primary target where I expected Aircraft Y. I requested Aircraft Y ensure his transponder was on. While waiting for that I continued with other tasks including clearing the other aircraft calling. I noticed the continued primary only target and multiple times requested a recycle of the transponder on Aircraft Y. Looking back; I should have still climbed Aircraft Y to a higher altitude while we sorted the transponder issue. However; I allowed the other aircraft to distract me. Meanwhile; Aircraft X made a course reversal and was now northbound and had climbed to 4;000 [feet]. At one point I noticed the primary target headed towards Aircraft X. I believe I asked Aircraft Y's altitude. They reported 4;000 feet; the same altitude as Aircraft X right in front of them about 3ish miles. Looking back; I should have immediately climbed them but I only issued an immediate left turn to heading 210. Slowing down to the microseconds; my thought process had added complexity from an extreme precipitation cell just south of Aircraft Y; thus a few more microseconds of processing to come up with a heading far enough away from Aircraft X but not so far to have the possibility of it being too close to the precipitation and thus risking Aircraft Y refusing the heading and having back and forth transmissions to find a suitable heading. There wasn't ANY time for back and forth transmissions; I had to get it right the first time. So this caused me to pause what seemed like a long time but was probably an extra second to give the heading 210. I wish I would have climbed at the same time. I immediately went to Aircraft X and issued a left turn away to I think 320 or 330 along with an immediate descent to 3;000 feet. All I could think was I had to separate these two aircraft heading close to each other. The 3;000 foot clearance was below my MIA (Minimum IFR Altitude); But I knew I had to immediately get SOME vertical separation and I know; from being a pilot myself; a C182 can drop fast. It was the fastest way to create separation I had. Climbing Aircraft Y; while I should have done that; would have a delay in response. The headings would have a delay in response. Telling a C182 pilot to turn and descend immediately while simultaneously issuing traffic was the quickest way to pull these planes apart. It was below my MIA; however the aircraft was VFR in VMC. It was the safest option I had; with the note I wish I would have ALSO climbed Aircraft Y. To recap; I first issued an immediate left turn to 210 to Aircraft Y; then quickly issued and immediate left turn to the NW and an immediate descent to 3;000 feet while calling the traffic to Aircraft X. Then I went back and issued traffic to Aircraft Y who I believe said he had visual on the traffic. There was a combination of garbled radio and foreign accent from Aircraft Y. Looking back I technically should have used the term Traffic Alert to both aircraft; but I still got the traffic calls out as soon as possible after attempting to separate the traffic. I asked Aircraft Y if they passed the traffic; they said yes and at some point I climbed them. I told Aircraft X to resume own navigation and altitude their discretion. There wasn't time to dwell as I still had many other tasks to complete. In the middle of this all another aircraft; possibly Aircraft Z questioned why they were leveling off. I had to instruct my low time D-side to do several tasks including point outs and coordination on Aircraft Y and other aircraft. It was probably 10 minutes before I slowed and was able to report the event to my supervisor. Before the two aircraft came together I attempted at least once; unsuccessfully; to track the data block on to the primary target. I don't recall exactly why my attempts were unsuccessful and the data block stayed near ZZZ1 coast track. I may have typed the input out of order or didn't click directly on the target.I should have climbed Aircraft Y earlier and I wish I was more successful at tracking the data block on the primary target. Having the data block tracking with the primary target would have prompted me to respond quicker. Task saturation fought me on all of this. While not directly related to this event; the sector frequencies have been absolutely horrendous for weeks. Well; they've been very bad for years; but especially awful the past weeks. We have 2 transmitter sites with Mains; Standbys; and BUECs (Backup Emergency Communication System). I; and everyone else; have to CONSTANTLY switch between all 6 radios to communicate with aircraft in various portions of the sectors!! Even high altitude! My supervisor has begged us to report the frequency issues. It is a disaster waiting to happen; and I'm not exaggerating. I think even this session I had to switch multiple radios to talk to aircraft in the flight levels. Not helping the issue is bad feedback on that frequency. Its actually some other constant transmission like someone talking. You can usually hear it as soon as you unkey the microphone. Since the 2 radio sites are cross linked; the site that is receive only usually picks it up when you unkeyed. Its hard to explain but VERY frustrating. Please fix this. Someone needs to go out there and track down that rogue transmission station and either shut it down or fix it. Someone is either transmitting on the same frequency in FM or some other mode or some other harmonic frequency issue or something.




Synopsis: A Center Controller reported a departing aircraft with an inoperative transponder climbed into confliction with an enroute VFR aircraft. The Controller descended the VFR aircraft to an altitude below the Minimum IFR Altitude to ensure separation.