54 Khz

[boochk]

**If this is the wrong place for this, my appologies**

Since this is a holiday weekend, I had time to do some evening listening. I have a Polimar loop system with loops from 50Khz thru 15Mhz. I decided to listen at the bottom end in the LF portion of the band. My AOR 5000 can listen as low as 5Khz so I started there. I found what sounds like the Navtex signals on 24Khz and 40.6Khz. As I tuned upwards, I found a signal I am unfamiliar with. It sounds like morse code but is so slow, I cannot follow it. The signal is different than the time signal on 60Khz. I started listening at 2300 and is still broadcasting at 0400 and now I can hear it with just a random dipole. Although I live within a few miles from Eglin AFB, I don't think the signal is from there. Can anyone identify any these signals? There is no information about 54Khz on google along with the 24Khz and 40.6Khz signals.

John

 

[BDM123]

Not sure. I found this is a Google search. I'm not hearing it here.

54 kHz
Call sign NDI,
250 kW ERP,
U.S. Navy submarine broadcast station,
Awase Peninsula, Okinawa, Japan

VLF Stations - Google Earth

 

[boochk]

BDM123 Thanks for the lead but I think this is doubtful from my location.

I have taken time to review what I can find.

40.75 Khz NAU - US Navy Aguada, Puerto Rico
24.0 kHz NAA - US Navy Cuttler Maine, USA

These seem plausible from my location. The super slow CW on 54 Khz I am hearing is still present at my location. (2230-2330 UTC) There are definite differences on short and long OOK. The signal is stronger than the 60 Khz time signal I receive from WWVB.

Has anyone else heard this frequency? I am hoping someone can guide me to an answer as to what this is.

Thanks,
John

 

[majoco]

I think this is doubtful from my location.

I don't see why - those VLF transmissions are designed to communicate with submarines all around the world. The subs have a veeery long insulated trailing antenna and the morse is very slow so that a special detector can pick the signal out of the noise. Hams have been doing it for a while with very narrow bandwidths on those VLF's.