no recordings available
see this nice letter and
the ppc from the files of Joop Balneger (1988)
------------------------------------------------------------
Callsigns:
NNN0NRO
Frequencies Voice:
13826
14391.5
16298
16298.5
16300
20373.5
20936
Frequencies Radioteletype:
13829
14385
14936
15982
16300
20373.5
20936
20937.5
Systems used:
75 Bd