Every day, I leave my HF radio on the 28.1246 MHz to listen for WSPR signals. My PC then decodes these and sends the reception reports up to WSPRNet website for others to see.
The QRSS (very slow morse code) band is just a few hundred Hz below the 10m WSPR band and I noticed in the WSPR waterfall that two QRSS signals were present so I had a look.
The image above shows the QRSS signals that I was hearing over a period of about 20-25 minutes on the 1st of November 2022.
VE1VDM in Canada and G0PKT in the east of England had reasonable signals and they were the two I had noticed initially. G6GN in England is also present but quite weak. There are other very weak QRSS signals as well but I was unable to ID these.
The locations of the relevant stations are shown on the map below.
VE1VDM in Nova Scotia is 4000kms from my location and is easily explained as it's an ideal one F2 layer hop away on 28 MHz.
The signals from G6GN at 400kms and G0PKT at 650 kms are not so easily explained. If it was the Summer months then we might think it was Sporadic-E but, this was the first of November AND G0PKT is pretty much there all of the time every day when the band is open.
I suspect that I am receiving these signals via F2 layer backscatter. In the past (pre digital days), backscatter signals were pretty much buried in the noise with the SSB and CW modes. Now however, WSPR has no problem decoding signals that are 20dB below the noise level and I can see QRSS signals which are in the region of -15 to -20dB.
I think a lot of those 'close in' signals that we are now seeing on WSPR or FT8 on 28 MHz are in reality via backscatter.
You can see from the map above all of the WSPR stations I heard on 28 MHz on the 1st of November. Meteor Scatter? Forward scatter via Sporadic-E? I'm opting for F2 layer backscatter.
I'm using an omni-directional vertical on 28 MHz so I can't beam headings. Maybe someone else wants to do some tests? See which direction those 'close in' signals are strongest. The direct path OR beaming in some other direction at a potential back-scatter point?
3 comments:
I have a 2el Moxon for 10m which I find very convenient with its 180 degree beamwidth but good F/B. Rotation is with a rope hanging from the boom.
I agree with F2 backscatter. I often hear and work VK2/VK3 on FT8 when beaming North. On the other hand a local (20KM away at Mackay) is very weak on the Moxon but strong on my 30m ground plane.
Nice to see you back on the blog.
73 Brian.
See you are receiving a WSPR signal from Pat Lawlesse's sail boat, OZ4PAT the Irish entrant in the GGR2022
Regards,
George
Glad to see you back, you are one of the only few blogs i follow....
28Mhz has been in excellent form this last few days, so i decided to leave WSPR running here, if you see me the call is F5VLY.
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