This is a situation in which a bare wire can work fine, but a properly sized antenna usually, but not always, will work better. Electromagnetic radiation (TV signals) have specific wavelengths (around half a meter for the signals in the TV band). An antenna the receiving elements of which are approximately this length or multiples of it will have higher gain (ability to receive) than will an arbitrarily sized wire. The OP's improvised antenna will work fine as long as the signal strength is reasonably high.
