Columbia AM is a low power AM (LPAM) station broadcasting from Aalst in the Netherlands. There are a few towns with the name Aalst, but this is the one at 51.78N 5.12E, along the river “Afgedamde Maas”. Beautiful area for cycling, my other big hobby! Aalst is only 37 kilometers SE from here, but particularly at night there is sometimes interference from Radio Seabreeze, another LPAM.
I received an e-QSL from Columbia AM for my report to studio@columbia-am.nl. Columbia AM has a long history as radio pirate. You can read more about that on their website.