Narrative:

Aircraft Y was southbound on L462 at flight level 370. After the aircraft progressed [to] dawin the pilot requested to climb to FL390. I verified with the d-side who was training at the time if aircraft Y was good for climb to FL390 and waited for him to coordinate the revised altitude with ttpp. He said yes and I ask again if there was anyone behind him to confirm. He said no; and then I issued the climb clearance. At some point while this was happening aircraft X was trying to call but the transmissions were breaking up due to a frequency blind spot in the area and I was distracted with switching transmitters and receivers to establish communications with aircraft X. To make matters worse our long range radar is out of service for maintenance so coverage is limited in that specific area. That is why I ask for the developmental to double check if aircraft Y was good for climb. When aircraft Y was climbing out of FL385; aircraft X appeared on radar about 7 miles behind and to the west of aircraft Y westbound. I advised aircraft Y about the unidentified traffic and ask if he had to respond to an RA. The reply from aircraft Y was negative.I could have made eye contact with the trainer to ensure that aircraft Y was good for climb. The frequency blind spots really need to be fixed and management needs to be more proactive about collecting data for resolution. The workforce has developed a workaround mentality and will not report it. If I was not distracted with establishing comms; I would have reached to mark the strip of aircraft X and seen the traffic.

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Original NASA ASRS Text

Title: Three controllers report of separation loss due to equipment issues related to frequency blind spots and long range radar being released to maintenance.

Narrative: Aircraft Y was southbound on L462 at flight level 370. After the aircraft progressed [to] DAWIN the pilot requested to climb to FL390. I verified with the D-side who was training at the time if Aircraft Y was good for climb to FL390 and waited for him to coordinate the revised altitude with TTPP. He said yes and I ask again if there was anyone behind him to confirm. He said no; and then I issued the climb clearance. At some point while this was happening Aircraft X was trying to call but the transmissions were breaking up due to a frequency blind spot in the area and I was distracted with switching transmitters and receivers to establish communications with Aircraft X. To make matters worse our long range radar is out of service for maintenance so coverage is limited in that specific area. That is why I ask for the Developmental to double check if Aircraft Y was good for climb. When Aircraft Y was climbing out of FL385; Aircraft X appeared on radar about 7 miles behind and to the west of Aircraft Y westbound. I advised Aircraft Y about the unidentified traffic and ask if he had to respond to an RA. The reply from Aircraft Y was negative.I could have made eye contact with the trainer to ensure that Aircraft Y was good for climb. The frequency blind spots really need to be fixed and Management needs to be more proactive about collecting data for resolution. The workforce has developed a workaround mentality and will not report it. If I was not distracted with establishing comms; I would have reached to mark the strip of Aircraft X and seen the traffic.

Data retrieved from NASA's ASRS site and automatically converted to unabbreviated mixed upper/lowercase text. This report is for informational purposes with no guarantee of accuracy. See NASA's ASRS site for official report.