Date: 201901
Local time of day: 0001-0600
Location: ZZZ.ARTCC, US
Flight conditions: VMC
Aircraft: Gulfstream G650
Operator: Corporate
Operating under: Part 135
Flight plan: IFR
Mission: Passenger
Flight phase: Climb
Airspace: Class A ZZZ
ATC / advisory: Center ZZZ
Second aircraft: B737 Undifferentiated or Other Model
Reporter organization: Government
Reporter function: Enroute
Reporter qualification: Air Traffic Control Fully Certified
Human factors: Fatigue; Physiological - Other; Situational Awareness; Communication Breakdown; Distraction; Time Pressure; Workload
Anomaly: ATC Issue All Types; Conflict Airborne Conflict; Deviation - Altitude Excursion From Assigned Altitude; Deviation / Discrepancy - Procedural Clearance
Detector: Automation Aircraft RA; Person Flight Crew
When detected: In-flight
Result: Air Traffic Control Issued Advisory / Alert; Air Traffic Control Separated Traffic; Flight Crew Became Reoriented; Flight Crew FLC complied w / Automation / Advisory
Contributing factors: Company Policy; ATC Equipment / Nav Facility / Buildings; Environment - Non Weather Related; Staffing; Human Factors
Primary problem: Human Factors

Narrative: Aircraft X was climbing. I had to stop the aircraft at 26;000 ft. for traffic at 27;000 ft. When cleared; I climbed Aircraft X to 28;000 ft. because of Aircraft Y at 29;000 ft. passing overhead. A few minutes later; Aircraft X reported an RA. I informed pilot that traffic was passing to the west 1;000 ft. above. Pilot respondent 'ROGER; leaving FL280 for FL380.' I replied 'Negative; maintain FL280. FL280 was your assigned altitude'. At this time; Aircraft Y informed me that they were responding to an RA also. I never observed Aircraft Y change altitude nor Aircraft X above 28;100 ft. The aircraft passed 2 miles abreast. Listening to the tape later; my clearance could have been garbled but the pilot read back FL380.In my opinion; fatigue and frequency issues could be a contributing factor. As far as fatigue; I have worked 28 days of overtime in the last 36 weeks; with 6 scheduled for the next 6 weeks. I am lower in hours than most on the overtime list and we are not even into the high leave part of the year. After 31 years of a 2-2-1 schedule; I can cope with the ups and downs of that; but throw in a random shift on my weekend; never knowing which day or which shift; it make rest hard. With our staffing levels it appears this will continue for the foreseeable future. Add in home life; and now the stress of having to work and not getting paid and my anxiety levels are at a peak. The burn-out factor and negativity is high; and I feel I speak for a lot of controllers here.As far as frequencies; they have been problematic for quite some time. Not as clear as they used to be; static on both the pilots side and ours; over all weak; with no clear plan for a fix. The SOC will change TELCO paths and it may clear them up momentarily but it is no true fix. The feeling around the control room is that no feels frequencies are a priority. We can't do our job without them. They are as important as the RADAR. I can't say any of these thing were truly contributory to this incident; but I also can't say they weren't.Need to listen more closely to read backs. Increase staffing. Clean up frequencies. Get the Government opened back up.




Synopsis: A Center Controller reported an aircraft misunderstood their traffic information; possibly due to poor radio coverage; and climbed above their assigned altitude into confliction with converging traffic.