[MilCom] EAM on VLF RTTY

[David L. Wilson]

>  > At 5:10pm PST on 02/23/2017 a 50
>  Hz shift 50 baud rtty signal around 21 kHz faded-in.
>  >   I don't know if it came
>  from a ground station or an E-6B that was in W260 at the  time.
>  >   The E-6 did
>  broadcast the same EAM on 311.
>  >    85
>  Hz shift was as close as I could get to 50 Hz shift with  MULTIPSK.
>  >    I'm wondering if
>  this was accidentaly sent in the clear.

IT was a E-6B--they do not do these on VLF ground stations in that mode.  The TACAMO aircraft *always* do the 50 Bd EAMs in the clear.  Why not, the same message goes out on voice on HF and does not mean anything to anyone else.  After 50 Bd they go to higher baud wider bandwidth.  When I first monitored them back in the 1979's, they came up in CW and also used 5 Bd (not a typo) RTTY.