The 12/26/07 of the ARRL Contest Rate Sheet had the following item:
Next time you open up your radio, consider that 55 years ago George Rose K2AH, made the first solid-state amateur transmission with a single-transistor homebrew rig. It used an RCA point-contact germanium transistor. Rose measured an input power of 24 mW and estimated the radiated power at somewhere around 50 uW. He made a contact with 25-mile distant W2UK and with W2KNI and W2DPB. (Thanks, Stew W5FYI)
On the qrp-l mailing list, Jason, NT7S, pointed us to AA1TJ’s 80m 1950′s “Retro” QRP Transmitter Web page. This page describes an 80m QRP rig bulit with a couple of 2N35 germanium transistors.
AA1TJ says, “I’m curious to know not only, “How low can I go?” but also, ‘How bad can the active components be?’ and still communicate.” The 2N35 was marketed as an audio transistor and the spec sheet claimed a maximum usable frequency of about 1 MHz. Even so, AA1TJ did manage to make the thing oscillate on 80m and make a few contacts!