Odd harmonic resonances of 80m dipole antenna

Odd harmonic resonances of 80m dipole antenna, center fed and mounted in inverted V configuration, being checked by a NanoVNA. Third harmonic, fifth harmonic and seventh harmonic near amateur radio bands are seen. There is no balun at feedpoint and the cable is 15m of RG213. Antenna wire has multiple joints. Apex is at 5.5m, on a galvanized iron pipe. Ends are at 3m and 2m from the ground. Overall it is a compromised antenna.