Compliments always welcome

I have just received an unexpected email from Michal, a Polish radio amateur, callsign SQ7JZI, who has been monitoring my longwave transmissions recently. He wrote, " Incredible VLF signal to 137KHz, congratulations. What equipment do you use ?"
Of course I had to tell him, and encourage him to radiate his own signal. Then there will be 3 from Poland on the 2190m band.
Signals on this band are rare; still none at all from many of Poland's neighbouring countries. I hope someone from there will one day be able to change that. It would certainly add interest.