This kind of ambient RF pickup was described in a 1970s Scientific American "Amateur Scientist" column. It required an antenna the size of a frying pan, however

This kind of ambient RF pickup was described in a 1970s Scientific American "Amateur Scientist" column. It required an antenna the size of a frying pan, however, for approximately the same net wattage. I am curious what Nokia's trick was (assuming the achievement was carried out in real life, rather than only on paper.)