Pilot reported an NMAC event during landing pattern practice with another aircraft entering the pattern for different runway.
Synopsis
Pilot reported an NMAC event during landing pattern practice with another aircraft entering the pattern for different runway.
Narrative
While completing takeoffs and landing within the traffic pattern at ZZZ I was involved in a near midair collision with Aircraft Y [Piper]. The Piper was entering the pattern at the same time I was preparing to turn downwind from crosswind. As I began turning a left downwind for Runway XX; the Piper was in front of me and above about 100 feet. I observed the Piper through my windshield and my TCAS system alerted that the traffic was within 100 ft. I made a radio call; leveled my altitude; and made a radio call to alert the Piper and continued to landing as normal Runway XX. The Piper followed in behind me without incident. I believe the Piper meant to enter a 4 midfield left downwind; but entered the pattern much earlier than intended. The Piper was also above me in a low wing airplane and descending into the pattern; and I don't believe the Piper ever saw me until I made a radio call. In addition; the radio call outs from the Piper seemed non standard and vague; and one even mentioned 'ZZZ1'; making it difficult to pinpoint the Pipers location and intentions. What could prevent this is a standard pattern entry from the Piper; and being at pattern entry altitude well before the pattern entry would have made it more likely the Piper would have seen me. Standard radio callouts are very helpful. I will begin making radio callouts during the crosswind leg. I will begin leveling out and flying a square crosswind to downwind turn to increase my own visibility to entering traffic.
Source: NASA Aviation Safety Reporting System (public domain). Reports are voluntary submissions and are not verified by NASA.