September 29, 1920: Joseph Horne Company's department stores sell radios that are already equipped with headphones and a button for tuning. In The Pittsburgh Sun the price is stated to be $10 or equivalent to over a hundred dollars today.
In 1920 the tuned radio frequency receiver (TRF) had a major improvement.The local oscilator and audio amplifier that were invented around that time were milestone improvements for the radio receiver. The radio receiver became simpler and cheaper than before because the loud speaker could now be integrated with the chassis of radio.
