8 Feb 2012

Weak signal modes compared

There has been quite a bit of debate recently about just how good certain weak signal modes are when compared against similar modes. So, ON7YD has done some research and straw polling to compare them and published the results on his wonderfully informative website. He asked people to try to decode some weak QRSS signals by eye - these were at defined S/N ratios and compared the results against OPERA at various speeds and WSPR.

Amongst his conclusions is that "Opera8, QRSS10 (or DFCW10) and WSPR should have a more or less equal performance."  This is very much as I have found from practical experience on 136kHz where QRSS3 does not perform as well as QRSS30 which is somewhat better than WSPR. So, WSPR being much the same as QRSS10 seems spot on. The advantage of WSPR is of course the internet database reporting which allows you to see where you have been received. QRSS reports depend on someone decoding the signals by eye and then manually sending you a report, which rarely happens. So, WSPR remains my favourite weak signal beaconing mode.
ON7YD's graph showing the effectiveness of various weak signal modes

3 comments:

Anonymous said...

Where is the link to the comparison article that has that image? I can't find it on the ON7YD Web Site. Tnx, David

Roger said...

http://on7yd.strobbe.eu/QRSS/ is the link.

Bert, PA1B said...

Hello Roger, Thank you for the fine diagram. I see that WSPR with an S/N of -29dB still gives 100% readability, so I will apply this figure in my Excel sheet to calculate the Lowest Possible Power in the analysis of WSPR spots. 73, Bert