QST Aug 1933 Collins 300B
First introduced in late 1933, the 300B was a 250 watt commercial market targeted phone and CW transmitter which also found application on the amateur bands. The 300B consisted of two medium size racks and employed two 203As in the output stage. These were modulated by two Class B 203As. This transmitter and its legacy 300D follow-on ran in production for several years and were one of Art’s more successful products.