| The WBR Regen Receiver was designed by N1BYT and appeared in the Aug 2001 issue of QST. A reprint can be found in the ARRL book "More QRP Power". This design stands out from almost all other regen designs by the fact that it utilizes a Wheatstone Bridge type arrangement of the tank cicuit. This serves to isolate the oscillator from the antenna, resulting in virtually no radiation into the antenna port - a common issue encountered with regens, which can cause hum. The receiver is very stable and has very low drift. It is also quite sensitive - pretty amazing for two transistors and an IC! I made a few changes to the original design. I substituted a wirewound pot for the regeneration control, and omitted the regen preset trimpot R5. Other changes included the substitution of the 2.2K resistor R12 for a 10K trimpot so that the lower end of the band coverage could be set exactly. I also followed the author's suggestion of using the audio chain from his OCRII receiver for a little more audio power. The OCRII also employs an LM386 IC, nut also has a 2N3904 preamp. While the LM386 IC in the OCRII doesn't have a 10uF cap between pins 1 and 8, I installed this component in order to get the maximum amplification. |
