Flight Crew Instrument
Flight Crew Last 90 Days 45; Flight Crew Total 2190; Flight Crew Type 2184
Communication Breakdown; Time Pressure
Conflict NMAC
Flight Crew Took Evasive Action
Environment - Non Weather Related; Human Factors; ATC Equipment / Nav Facility / Buildings
I was approaching FNL from the southeast with the intention to land. When 10 miles out and at pattern altitude; I called the temporary Tower to report my position and intentions. I was instructed to report 4 miles out. When 4 miles out; I reported and was instructed to enter the midfield left downwind for Runway 15. I was also informed to look for departing traffic headed to the northwest. Suddenly; my ADS-B traffic alerted me to traffic at same altitude; same position. I saw a low wing aircraft at the top left of my windscreen headed for me. The other pilot dived and passed approximately 300 feet under me and continued seemingly barely missing two water towers seemingly flying between them.  It should be noted that the tower at FNL is temporary and has no current access to radar but relies on visual observation from the ground level. Though; radar has been installed; it has not been certified for almost a year now due to FAA imposed Covid restrictions. Seems to me that having radar access would have avoided this situation and not having radar is likely to lead to similar such close calls.
GA Single Pilot reported an NMAC event with departure traffic while entering landing pattern. The temporary Tower without radar access was a contributing factor.