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UnID signal 26-28 kHz longwave

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dlwtrunked

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#4
I was wondering if that was the case... I never heard it in that band before. Thanks!

Brett
Definitely ALE on HF somehow looking falsely like a VLF signal. One thing all should know is that transmitting a signal this wide on VLF is simply not possible due to antenna tuning issues.

Were you using a converter? If so, what is the offset frequency? If so, I bet you still receive that signal without the converter. If not co.nverter, it is likely an "aliased" frequency (which can occur in an SDR without being filtered out and technically something different than an "image")
 
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#5
Definitely ALE on HF somehow looking falsely like a VLF signal. One thing all should know is that transmitting a signal this wide on VLF is simply not possible due to antenna tuning issues.

Were you using a converter? If so, what is the offset frequency? If so, I bet you still receive that signal without the converter. If not co.nverter, it is likely an "aliased" frequency (which can occur in an SDR without being filtered out and technically something different than an "image")
It was recorded on a Perseus SDR at a sampling rate of 2MS/s with a center frequency of 1000 kHz (for the MW band); the Perseus native application filters out below 200 kHz at this CF, but HDSDR lets me play back down to 0 Hz so I like to use it to explore the bottom of the band. I never noticed any false signals there before, but this obviously is a signal that isn't really there.

Brett
 
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#6
I tried a few decoders on it and can't get the decoder to align with the signal. It'd be nice to see who the ale sender was.
 
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#7
To me it sounds a bit like Olivia 8 but it's sending the same thing over and over.

Listen to all of these and pick one!

https://www.nonstopsystems.com/radio/radio-sounds.html#PSK

But then....

From...

http://www.udxf.nl/ELF-VLF-GUIDE-v1.0.pdf

00027.0:RCV:Russian Navy, Rostov na Donu, RUSSIA:unid
NOT ACTIVE
RCV Rostov na Donu 47N18 39E48 is presumed shut down or reused
00027.0:NAU/NWC:US Navy Aguada/Harold E. Holt, USA/AUSTRALIA:MSK
NOT ACTIVE
NAU NRTF Aguada, is shut down on VLF. Operational at LF, 00040.75 kHz
NWC is currently only active at; 00019.8 kHz ( see this )
00027.0:unid:US NAVY TACAMO, mobile worldwide:F1B-50Hz/190Hz/MSK 400Hz/800Hz BW
NO INFO
TACAMO is an acronym for; TAke Charge And Move Out
00027.0:KS2XAL:TCOM L.P, Elizabeth City, North Carolina, USA:unid
NO RECENT INFO
TCOM performed VLF longwire-antenna tests, at the former Weeksville Naval Air
Station, using a tethered balloon.
00027.0:FTA27: St Assise, FRANCE
NO RECENT INFO
00027.2:unid:US NAVY TACAMO, mobile worldwide:F1B-50Hz/190Hz/MSK 400Hz/800Hz BW
NO INFO
TACAMO is an acronym for; TAke Charge And Move Out
00027.3:RDL:CIS MIL HQ Moskva VLF network,RUSSIA:N0N/A1A/F1B-T600 75 Hz
PRESUMED ACTIVE, but no recent info
This RDL station is presumed located in the far-east or arctic RUSSIA.
The station was previously using a hh:09 – hh:19 – hh:29 – hh:59 schedule. No regular
transmissions at hh:39 and hh:49. Frequent flash-override messages, in-between the
scheduled transmission times, using FSK 75Hz morse.
00027.5:NAU:US Navy NRTF Aguada, Puerto Rico, USA:MSK
NOT ACTIVE
NAU NRTF Aguada, is shut down on VLF. Operational at LF, 00040.75 kHz
00027.5:unid:US NAVY TACAMO, mobile worldwide:F1B-50Hz/190Hz/MSK 400Hz/800Hz BW
NO INFO
TACAMO is an acronym for; TAke Charge And Move Out
00027.5:EWC4:Russian Navy, Vladivostok, RUSSIA:unid
NOT ACTIVE
EWC4 Vladivostok 43N08 131E54 is presumed shut down or reused
00027.6:NOV:US NAVY TACAMO LANT, mobile Atlantic Ocean:F1B-50Hz/190Hz/MSK
400Hz/800Hz BW
NO INFO
TACAMO is an acronym for; TAke Charge And Move Out
00027.7:3SB:Chinese Navy, Datong, PEOPLES REPUBLIC of CHINA:A1A/unid
PRESUMED NOT ACTIVE
Of the 22 listed VLF frequencies for the Chinese Navy, only 20.6 kHz, in use
by 3SA Changde / 3SB Datong, is recently reported with traffic.
00027.7:unid:US NAVY TACAMO, mobile worldwide:F1B-50Hz/190Hz/MSK 400Hz/800Hz BW
NO INFO
TACAMO is an acronym for; TAke Charge And Move Out
00027.9:NJB:US NAVY TACAMO PAC, mobile Pacific Ocean:F1B-50Hz/190Hz/MSK
400Hz/800Hz BW
NO INFO
TACAMO is an acronym for; TAke Charge And Move Out
[/unquote]
 
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