Air carrier flight crew reported radio altimeter malfunction on approach to MEM airport and speculated possible 5G interference as a contributing factor.

Narrative

Weather was clear during the daytime landing. We were on approach to 36L at MEM when at about 1200 ft. AGL we received numerous callouts from the airplane; including (don't know the order) '20'; '10'; 'go around;' 'too low terrain' etc. while the Captain's radar altimeter was fluctuating wildly. We went around. ATC gave us vectors to try again. We discussed the situation and decided if it occurred again; we would continue to a landing. We were day VFR at a very familiar airport. We knew the terrain and that all warnings were erroneous. The second time at virtually the exact same spot and altitude; it happened again. And again the radar altimeter was fluctuating. As briefed; we continued. The warnings lasted probably 10 seconds. After that; they went away; everything; including radar altimeter; was normal. We landed uneventfully. Cause is unknown; although the fact that it occurred twice at about the same place leads me to believe it may have been some kind of interference from something on the ground.