HFU HF Underground

Loggings => HF Mystery Signals => Topic started by: minorukun on January 16, 2023, 2205 UTC

Title: UNID bird song 8392 usb 2130z KiwiSDR Wessex
Post by: minorukun on January 16, 2023, 2205 UTC
found here http://wessex.zapto.org:8073/

strange bird-like signal, never heard before. Center frequency is about 8393.5, bandwidth ~500Hz

https://vocaroo.com/1753uEHVCM6n

no good screenshots with kiwiSDR, this one is from fldigi
(https://i.ibb.co/BgR82DB/2023-01-17-00-42-11.jpg) (https://ibb.co/BgR82DB)

very faint on University of Twente

lasted at least a hour, then peskadores arrived to interfere
Title: Re: UNID bird song 8392 usb 2130z KiwiSDR Wessex
Post by: Token on January 17, 2023, 1508 UTC
This is a broken Morse code transmitter.  In this case it might be the Chinese station known as MC03, it often shows this failure.

See one of my old videos on this kind of signal here 

https://www.youtube.com/watch?v=OPeTx9FSfEs

T!
Title: Re: UNID bird song 8392 usb 2130z KiwiSDR Wessex
Post by: Pigmeat on January 17, 2023, 1532 UTC
We should dub it "The Chinese Birdman".
Title: Re: UNID bird song 8392 usb 2130z KiwiSDR Wessex
Post by: Token on January 17, 2023, 1547 UTC
We should dub it "The Chinese Birdman".

Unfortunately, this is not the only signal I see with a transmitter doing this, there is also a Russian signal that I see doing this occasionally.  The Chinese MC03 is just the one I see most often.  The fact that it has often, for years on end, done this makes me wonder if the techs / operators know and do not care.  Since the transmission is most likely machine received I wonder if the decoding hardware does not care, copies fine despite the chirp, and so the operators don't care either.

T!
Title: Re: UNID bird song 8392 usb 2130z KiwiSDR Wessex
Post by: Token on January 18, 2023, 1321 UTC
Following up on this.  I have it tuned on the home receiver right now (1315 UTC, 18 Jan 2023) and it is indeed Chinese MC03.

Looking at my logs I have been seeing this signal, off and on, in this condition since at least 2013.  I have also seen it in clean Morse.

T!
Title: Re: UNID bird song 8392 usb 2130z KiwiSDR Wessex
Post by: minorukun on January 18, 2023, 1845 UTC
huh, thanks for explanation