Some years ago, QST had an article on a crystal set based on a zero bias MOSFET. Although I have yet to try this sort of design I have no doubt they will work well. Crystal sets derive all their power from the TX and in the past I have achieved some remarkable (well for me!) results. Best was receiving Radio Australia (from Australia) as well as some amateur Gs on 80m and 160m at a considerable distance. In the USA some 75m AM amateur stations are regularly heard at great distances.