Last update: 3/23/04
Rick Campbell, KK7B's, modules and the QST articles describing them:
The R1 DC receiver: "High-Performance Direct-Conversion Receivers",
August 1992 (online at http://www.arrl.org/tis/info/pdf/9208019.pdf). You
still need to read this even if you're interested in the R2 below.
The R2 single-signal direct conversion receiver (a kind of phasing SSB
exciter in reverse!): "High-Performance, Single-Signal Direct-Conversion
Receivers", January 1993 (online at
http://www.arrl.org/tis/info/pdf/9301032.pdf)
The T2 phasing SSB exciter: "A Multimode Phasing Exciter for 1 to 500
MHz", April 1993 (online at http://www.arrl.org/tis/info/pdf/9304027.pdf)
Using these as a 2-meter microwave transverter IF: "Single-Conversion
Microwave SSB/CW Transceivers", May 1993
The miniR2 RX board (smaller, less current draw) and a complete 1-watt 20
meter CW station: "A Small High-Performance CW Transceiver", November
1995
The author revisits the noise figure question: Direct-Conversion Receiver
Noise Figure, in "Technical Correspondence," February 1996, and describes
several significant and excellent mods!
Kit Info
The basic modules are available as kits (or you can get bare PC
boards) from Kanga US. The original R2 is not now available, but the
R2Pro and miniR2 are available, and you can get a PC board template for
the original R2 article in .pdf format from ARRL