?? ?????? ??????? ???? ?? ????? ???????? ??????? ?? ????? ?? ???? ????? ????? ??. ????? ?? ???? ?? ???? ???? ?????? ?? ???? ?? ???? ????????? ?????? ??? ??? ??? ?? ???? ???.??????? ????????: ???? ?? ??????? ??? ??????? ??? ???????? ?????? ?? ??????? ??????? ?????.To begin with these equipment were large and sophisticated. After Lee de Forest invent