I decided to build a coat-hanger antenna last weekend. It required 6 coat hangers, one long block of wood, screws/washers and a balun (UHF/VHF converter). The whole project cost less than $10 and now the signal strength is 100% on all channels. In fact the TV reports 100% at 24dB where as the signal is as strong as 30dB on some channels! And the antenna isn’t even positioned precisely. I just dropped it next to the window. Lesson learnt – never spend money on a TV antenna.
Instructions to build your own are on YouTube.