Recently we’ve done a successful transmission from an earth dipole on 8270 Hz.
This is the first amateur transmission on VLF from Poland which has been received in another country. This is also the record distance for a transmission using a ground dipole antenna – over 1330 km.
Link to Paul Nicholson’s post about it: https://klubnl.pl/rsgb_lf_group-archives/html/rsgb_lf_group/2019-03/msg00025.html
Link to Paul’s VLF milestones list: http://abelian.org/vlf/amateur-radio/
This is probably the first VLF signal which has been transmitted from Poland after World War II. We are not aware of any military or other transmissions. Before the war we had the Babice Transatlantic Radiostation (callsigns AXO/AXL/SPO/SPL), which was similar to Grimeton/SAQ.