) ▁and ▁se cur ing ▁the ▁rights ▁to ▁programming . ▁Because ▁of ▁this ▁lack ▁of ▁restriction , ▁channel ▁dr ift ▁( the ▁shift ▁of ▁a ▁channel ' s ▁programming ▁format ▁away ▁from ▁that ▁which ▁it ▁originally ▁maintained ) ▁is ▁much ▁more ▁common ▁in ▁the ▁United ▁States ▁than ▁in ▁other ▁countries . ▁ ▁Because ▁the ▁United ▁States ▁had ▁relatively ▁weak ▁copy right ▁terms ▁until ▁ 1 9 7 6 , ▁a ▁large ▁body ▁of ▁older ▁television ▁series ▁have ▁la ps ed ▁into ▁the ▁public ▁domain ▁and ▁are ▁thus ▁free ▁to ▁red ist ribute ▁in ▁any ▁form . ▁ ▁History ▁of ▁American ▁television ▁ ▁After ▁years ▁of ▁experimental ▁broadcast s , ▁television ▁first ▁became ▁commercial ized ▁in ▁the ▁United ▁States ▁in ▁New ▁York ▁City ▁on ▁July ▁ 1 , ▁ 1 9 4 1 , ▁initially ▁by ▁R CA ▁( through ▁N BC , ▁which ▁it ▁owned ) ▁via ▁its ▁station ▁W NB T ▁( now ▁W N BC ) ▁and ▁CBS , ▁via ▁their ▁station ▁W CB W ▁( now ▁W C BS - TV ). ▁A ▁number ▁of ▁different ▁broadcast ▁systems ▁had ▁been ▁developed ▁through ▁the ▁end ▁of ▁the ▁ 1 9 3 0 s ; ▁most ▁ 1 9 3 0 s ▁efforts ▁used ▁low - band width ▁( and ▁low - f idel ity ) ▁mechanical ▁television ▁processes . ▁The ▁earliest ▁regularly ▁scheduled ▁American ▁television ▁shows ▁( including ▁variety ▁shows , ▁piano ▁less ons ▁and ▁a ▁murder - m yst ery ▁series ) ▁were ▁broadcast ▁via ▁mechanical ▁television ▁in ▁the ▁early