To radio hams on PF: What is this slow digital mode?

[Swamp Thing]

I was decoding WSPR signals on a KiwiSDR web receiver when I noticed a different kind of signal to the left of the cluster of WSPR signals...

The green filter indicator in the black frequency scale at the top shows where WSPR signals are coming in. There is one unknown type of signal just above 10.140 MHz, and another below it.

These signals run at about 1/3 bits per second, which is slower than the WSPR one. They don't seem to be limited to the one-minute time slot that WSPR follows.

What are these and what do I need to decode them?

 

[Baluncore]

The signals above and below 10.140 MHz are FSK signals.
You have no scale for the time or the frequency, so I cannot identify the bit rate or the frequency shift. You can extract those details from your data display. You will then need to identify the serial data start and stop, number of data bits and parity etc.

 

[Swamp Thing]

Yes, it is FSK of course. But more specifically, from this article it seems likely that the signal is what hams call "QRSS" .... https://swharden.com/blog/2020-10-03-new-age-of-qrss/ .

It feels like more of a quirky fun mode than a serious way to transmit information efficiently: Most users decode it visually by watching the waterfall, in which the shifted frequency conveys the dots and dashes of GOMC (good old Morse code).

The fact that it is below the WSPR band segment (wspr is another low power mode popular with hams) -- confirms that it is probably QRSS. (See frequency list in the article)Edit:
Fun fact.... "Atmospheric phenomena and other special conditions can often be spotted in QRSS spectrograms" :

 

[Vanadium 50]

What a cool site/set of sites!
5MHz sounds much better from Hawaii than Colorado!

 

[Baluncore]

Yes, QRSS is possible.
I would need to see more record to read anything beyond "5A".

 

[Vanadium 50]

Maybe this belongs in the technical forums...

Been playing with this. Very impressive.

HF propagation is stranger than I would have guessed. I found a station in NY that had a clear as a bell WWVH signal, but couldn't pick up WWV at all. I'd expect this from the 6m band, which is known to be wacky, but not at HF.

There are two features on the waterfall plot I don't understand. One is horizontal lines, i.e. power at all frequencies. An artifact? Or lightning? Or something else. The other is even stranger - a line that is roughly diagonal from 10 MHz (maybe lower) to 30 MHz, taking tens of seconds to work its way up. I am sure this is some artifact, but of what? An antenna tuner in the same shack? A stuck bit? Any ideas?

 

[Baluncore]

A clean image example would be helpful.

Lightning produces broad spectrum pulses. A digital noise blanker should detect and remove the big ones, and replace them with zeros, in the time-data stream. Then they will not appear in the image.

The other is even stranger - a line that is roughly diagonal from 10 MHz (maybe lower) to 30 MHz, taking tens of seconds to work its way up.

That is an Ionosonde transmitter. Ionosondes usually sweep from low frequency to high, at a steady rate. They are a slow, vertical incidence, chirp radar, that measures the changing reflectivity of the ionosphere.

Bottom-up ionosondes operate from the ground.
Top-down ionosondes operate from satellites.

You only hear or see them in quiet parts of the band, when there is propagation from their site to your location.
https://en.wikipedia.org/wiki/Ionosonde

 

[Vanadium 50]

A clean image example would be helpful.

No kidding. And, as is typical, I couldn't get it to do it when I was ready to take a screen shot. Grrrr... Watched pot and all.