I built a new aerial following some guides online (4-bay bowtie, 8" whiskers).

I'm in Titahi Bay and the transmitter is on Mt Kaukau at 202° to the south (according to Matchmaster). I've mounted the aerial facing that direction and tuned my TV.

Every channel comes in with a 100% signal except for Three and Bravo which are unwatchable.

I'm wondering that maybe my antenna whiskers are the wrong length or there's something else amiss.

Any ideas?