HFU HF Underground

Loggings => HF Mystery Signals => Topic started by: alleycat on March 30, 2021, 0143 UTC

Title: Amateur mode 7040kHz PSK variant?
Post by: alleycat on March 30, 2021, 0143 UTC
I'm seeing 2-minute long narrowband (roughly 75 Hz wide?) digital QSOs on 7040 kHz that I can't identify (apparently nothing similar at SigIdWiki). I think it might be some variant of PSK based on the resources at http://www.w1hkj.com/modes/index.htm (http://www.w1hkj.com/modes/index.htm), but I ran through all these modes in MultiPSK to no avail. Audio at https://www.lutins.org/temp/radio/7040_digi.mp3 (https://www.lutins.org/temp/radio/7040_digi.mp3) waterfall as shown below. Thanks for any assistance!
(https://www.lutins.org/temp/radio/7040_digi.jpg)
Title: Re: Amateur mode 7040kHz PSK variant?
Post by: Que si es? on November 01, 2024, 0318 UTC
I hear it too.  All day long.  Tunkhannock, PA.  Haven't been able to identify it. I thought maybe it was something local, like noise from an appliance or a charger or something,  but I'm picking it up on webSDR all over the country.
Title: Re: Amateur mode 7040kHz PSK variant?
Post by: RAH on January 03, 2025, 1926 UTC
You are hearing WSPR. The frequency is actually 7.038.6 Mhz. You can download WSJT-X and decode it. Under Mode select WSPR. The receive sequence takes 2 minutes.