basic radio with FET for AM and Shortwave (limited selectivity) скачать в хорошем качестве

basic radio with FET for AM and Shortwave (limited selectivity)

Shematic from a 3 transistor radio (direct reception, no superheterodyne) to receive radio stations on MW (600 KHz - 1,6 MHz) and Shortwave (2-12 MHz). The selectivity is limited, but is very good on medium wave with a suitable MW coil (see earlier video from this day, 30 may 2015) and can also work very properly for e.g. fax on SW (3-4 MHz) on one and only fixed radio station with an optimized L-C coil with a high Q. With this setup you can receive a few strong radio stations on SW, it depends on the antenna coil that you have made. VERY IMPORTANT: a loosely coupling to the antenna via a cap. from 2,2 pF up to 14 pF is necessary. If not: you don't receive anything at all (!). The detection diode is the obsolete oA 81, find a modern Germanium equivalent (perhaps a 1N90). An antenna from 1-2 meter needs no coupling capacitor to the gate from the FET. More electronics in my books on the Lulu website, author Ko Tilman.