I am located in Epuni in Lower hutt, I think this is a high coverage zone.

I have plugged my TV (built-in Freeview) to the existing aerial, pretty sure it's an old VHF type, and can receive all the TVNZ channels (via freeview), but nothing else.

I can also stick a standard piece of speaker cable into the aerial plug on the TV and get all channels (although this is far from ideal and I experience a few drop-outs).

Do I actually need to buy a dedicated UHF aerial or are there some tricks I could do to get the remaining channels through my existing aerial, i.e. point it somewehre else??

Any help is appreciated.