My mum's TV now has trouble producing clear pictures off an old high-gain UHF antenna dating back to when SKY installed it in the mid-1990's. The TV is plugged into a small amplifier which is then plugged into the cable that goes to the antenna. This system has worked well for Freeview's UHF service for several years until fairly recently. Her home is in Kohimarama (Eastern Suburbs of Auckland) and the UHF antenna is pointed toward Pine Hill on the North Shore.

About two years back there was a big storm and the UHF antenna fell off the metal pole and came to a rest on the roof, out of alignment with the TX but to my surprise the TV still managed obtain a clear signal with the occasional issues (usually during severe weather events). Somehow the antenna was put back onto the pole and seems to be properly aligned with Pinehil again. The current issue has only cropped up quite some time after the antenna was put back onto the pole.

Currently it regularly oscillates between providing a reasonable signal to a degraded signal then back to reasonable again and so on forth. I have some snaps from her Sony TV showing the signal details at its best and at its worst.

Happy to hear any suggestions of what I can look into. If it looks like I need to get someone in to have a proper look and/or fix something I would appreciate recommendations for firms/people I can contact to do that work.

Thanks in advance! :)