Hi there, Lets hope their using a suttle disguised antenna....
Does Anyone know about a crafty antenna system, they used in the Netherlands, way back

Cunning Idea was I think, Four of, Very Low Horizontal wires, in a sort of box layout,(2 above 2) Phased, so it that Cancelled towards horizon,
making the signal Mostly go Upwards, Idea was to try to make it harder to DF, and harder to see by enforcement

Not sure what frequency they used, Obviously in the Extended band (above 1602khz) to attempt NVIS effect
https://en.wikipedia.org/wiki/Near_vertical_incidence_skywave#:~:text=An%20NVIS%20antenna%20configuration%20is,%E2%81%A0%20wave%20above%20the%20ground.
Rod Watts