A simple radio is presented for your enjoyment of the AM radio band. If you've seen or built a CK722 model radio, the Am3 Radio is directly descended from that 1st generation hobbyist receiver. The tuning section is both detected and directly amplfied by the one transistor circuit. The Am3 Radio has very good reception using newer technology: the transistor signal gain of the MPSA18 Silicon transistor is 700+, the capacitors are of very high Q (about 2000) and designed for the purpose used, and the cake-frosting cans have very low loss. Some things are the same, the resistors, wire, the crystal earphones, and the ceramic trimmer.
The Am3 Radio illustrates the progress made to the simple design of the CK722 radios some 60 years ago. Volume is adequate for the listener for the most part. The Am3 Radio takes very little power from a pair of AA cells only 100uA at 3 Volts. No soldering iron is needed if using a "Solderless Breadboard" to assemble the circuit. There is no need for an external antenna: the set works quite well using just the telephone ground. I hope you enjoy building and listening to the Am3 Radio.
The Am3 Radio Revision H3 using a high-gain transistor as the detector and amplifier.
This PDF file is the log for the Kaito WRX911 Tecsun R-911 Analog, Tecsun PL-200, PL-210 PLL & Tecsun PL-310 DSP Ultra-Light spotter radios. On 02/10/2013, these sets combined for a total of 601 stations heard, on the 7th anniversary of UL RXing.
This PDF file describes the Am3 Score Formula that accounts the subjective 'High Quality DX' of the receiver, location, and conditions.