This is one of the most simple designs that you will ever find for 80m or 40m RX. It will readily scale to 160m or 60m. I went on to make a transceiver version based on an idea from W2UW (SK). Imagine that - a complete transceiver using just 1 FET (see the FETer).
See https://sites.google.com/view/g3xbm4/home/hf-mf-and-lf/homebrew/80m-or-40m-regen-rx .