2024 10m QRSS Challenge: - G0PKT, G0MBA & AE0V 15th Jan

As part of a challenge for 2024, I've decided to see how many QRSS signals I could capture on the 28 MHz band during the year.

QRSS are very slow morse code transmissions where the dots and dashes are several seconds long and the signals are decoded by looking at a waterfall display on a screen rather than listening to the signal.

The QRSS signals are usually just below the WSPR signals on the amateur radio bands. This means it's possible to have your PC decoding WSPR signals up around 1500 Hz while you look at the QRSS signals about 500 Hz or so lower in the audio spectrum at the same time.

2024 #3 & #4 - G0MBA & G0PKT... The QRSS signals shown above were captured at about 10:40 UTC and it shows the QRSS trace from G0MBA and G0PKT who are 650kms to the east of my location in Essex, England. From what I know, I think both are running 0.2-watts into vertical antennas.

You'll notice that the signals have a slight 'fuzz' as opposed to a clean tone. I hear/see these two stations practically every day and I think the signals are F2 layer backscatter. If I was to try again during the Sporadic-E season during the summer, both signals would be nice and clean.

At 650kms, both signals from G0MBA & G0PKT are way too far for ground wave and too close for normal F2. The signals are probably being propagated off the F2 layer, being reflected in some distant region and then returning to my location.

2024 #5 - AE0V...In the afternoon, I got a capture of the QRSS signal of AE0V in Minnesota (EN34FU) in the USA who is about 6,000kms from my location.

Ned, AE0V reports using a solar powered transmitter with no battery storage running 100mW into a 1/4 wave stainless whip about 8m above the ground.

The signal from the USA is easily explained as it's via multi-hop F2 layer propagation. 

In summary... That brings the QRSS tally so far for 2024 up to 5-callsigns & 3 DXCC.

1) 08 Jan 2024: VE1VDM - DXCC #1
2) 10 Jan 2024: VA1VM
3) 15th Jan 2024: G0MBA - DXCC #2

4) 15th Jan 2024: G0PKT

5) 15th Jan 2024: AE0V - DXCC #3

Backscatter on 28 MHz - 2nd Nov 2023

For well over 12-months, I have had my radio tuned to the WSPR frequency of 28.1246 MHz on the 10m band and I feed the decoded signals up to the WSPRnet website.

While I can see the WSPR signals clearly on the waterfall display, I can also see the very slow morse QRSS signals as well just a few hundred Hz below.

The image above shows the QRSS signals I could see on the 2nd of November 2023 and the locations of the stations are shown in the map at the start of the post.

The screenshot above shows a good capture of AE0V in the USA at about a distance of 6000kms. Ned, AE0V reports using a solar powered transmitter with no battery storage running 100mW into a 1/4 lamba stainless whip about 8m above the ground.

The signals from the USA and Canada are easily explained as they are via F2 layer propagation. The signals I find unusual are the ones from the England which are in the region of 500 to 650kms.

The trace from the 0.2-watt signals of G0PKT and G0MBA are there nearly all the time when the band is open. It's not F2 propagation in the usual sense as it's too close and it's not Sporadic-E.

I believe that it's backscatter just like what the military use for their over the horizon radar systems (OTHR). 

In this case, the 28 MHz band is open with F2 layer propagation and the signals from G0PKT & G0MBA are being reflected back towards my location from some distant point.

As an example of how consistent these signals are, I have decoded the WSPR signal of G0PKT about 1,000 times in the last 3-weeks. And that's a signal that's supposed to be in my 'skip zone' where it's supposed to be hard to reach.

There's nothing new about this, it's just that in this modern age of weak signal modes and waterfall displays, we can now see these very weak signals more clearly. 

If you're using FT8 on the higher HF bands and you see lots of reports from stations that about 200-600kms away then F2 backscatter is probably the reason.