Sorry I have tried searching for this but can't find a straight forward answer to the question.

I have been trying to get Freeview Terrestrial going (in addition to the existing DVB-S service we use). We moved into the house a year ago. After testing various pieces of the system, I think I have narrowed the problem down to the UHF antenna. If I disconnect the cable from the masthead amp, and measure the resistance using a multimeter, I get an open circuit (well 1.4 Mohm). The connections on the antenna itself look very corroded. Is that definitely a sign of a problem? By way of comparison, the VHF antenna gives a short circuit (0 ohm) reading. Just looking for confirmation before I get the UHF antenna replaced.