Based on my experiences with some replicas of the RIM Trabant KM, I undertook various attempts to solve the specific problems of regenerative receiver circuits with bipolar transistor. Those arrangements, however, became much more complicated and less reproducible without really effecting any significant improvements. For example, I have tried with moderate success to reduce the damping of the resonant circuit by using a darlington configuration, or to minimize synchronization effects by using separate transistors for demodulation and regeneration. But then I tried field-effect transistors and was very surprised by the success. The results achieved came very close to those of tube circuits.
Since I always feel it interesting to find the simplest usable variant for circuit types, I came to a solution with a regenerative detector using a FET, followed by an audio amplification stage, how presented with this schematic. The circuit with the FET offered much greater gain and less overdrive phenomena at the same time better selectivity. Synchronization effects only occurred at very strong signal strengths. Consequently, even with the single-stage transistor amplifier, a sufficiently loud headphone reception of amateur radio stations could be achieved.
I built such a device, designed as a monoband receiver for the 80m band, in a plastic housing. To enable speaker reception, I later replaced the single-stage audio amplifier by a circuit with the LM386. Despite the very simple circuit, the device offered a very usable reception of amateur radio transmissions in the operating modes SSB and CW. The feedback oscillation had soft onset, so that always the best setting could be found without effort.
Read, listen and watch!
Sanaphantastron is a somewhat unusual music project outside of mainstream.
On this website you can get lots of interesting information about it and hear music from Sanaphantastron. We hope you enjoy reading and listening!
here you can hear different music from Sanaphantastron. It is selected in an infinite loop by random generator. So you can run this link like an internet radio on the side.
what nobody needs...
...and hardly anyone likes to hear. The main thing is to make it makes fun!
Sanaphantastron is a mixture of a traditional music combo of different orientations and an experimental music project.