08-04-2013, 11:18 PM
This project grew from the "Lash up direct conversion receiver" thread which was started some time ago. I thought it would be better if I did a seperate thread on it in the relavent section.
Enclosed is the first part of the schematic as developed to date, the second part which I will post later will just be a simple AF Output stage.
I will probably add and on board VFO in the Mixer stage and possibly a sharp AF notch filter in the audio stage centered for CW reception somewhere between 400 Hz to 1 Khz and a switchable 2.8Khz roll off filter for SSB. The PSU and speaker plus the speaker matching transformer will be external. All components shown on the schematic are from my junk box and were all I had to hand so they are not to be taken as the ideal values but they are in the ball park as the receiver works very well.
Lawrence.
Enclosed is the first part of the schematic as developed to date, the second part which I will post later will just be a simple AF Output stage.
I will probably add and on board VFO in the Mixer stage and possibly a sharp AF notch filter in the audio stage centered for CW reception somewhere between 400 Hz to 1 Khz and a switchable 2.8Khz roll off filter for SSB. The PSU and speaker plus the speaker matching transformer will be external. All components shown on the schematic are from my junk box and were all I had to hand so they are not to be taken as the ideal values but they are in the ball park as the receiver works very well.
Lawrence.