Info about the extra aerials on the Terk ZSS clones
The Terk HDTVi and the amplified HDTVa both actually come with the aerials. They neatly fold into the the sides when not in use so that's why you probably never noticed them before. It actually is an improvement on the Silver Sensor design because it enables you to also receive VHF HD signals as well as UHF. Of course, there would have to be VHF HD signals available in your area which in Canada seems rare but I believe they are more common in the States.