no recording available
from the collection of Rudy van Dalen, here is an interesting
letter from 1981
Udo Rostalski submitted this nice QSL card from 1994
------------------------------------------------------------
Callsigns:
GKZ *
Frequencies Voice:
1869
1925
2182
2684
2810
Frequencies Radioteletype:
3607.3
3624
Systems used:
AUTOSPEC
SITOR
.