
As antenna I used my multi-turn 1m square loop inside the shack, turned so that I minimized the received noise. Moreover the loop tunes about 230 to 450 kHz, with a very low Q at the high end, so 500 kHz is a bit border line for its current configuration.
Nevertheless, buried in the noise I could receive PA0A about 900km away. Go figure on the NDB band I am able to read only 3 signals, the furthest being just 60km from my antenna!
So the loop is not that bad. The location needs improvement. I will move the loop outside, on the balcony. Then with a warmer season I might try to move in a less RF-polluted environment.