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I've been experimenting with WSPR to determine the decode probability of other digital modes. The attached chart illustrates the calculated results applied to a few popular modes. It shows whether the SNR of particular mode is likely to be above or below it's decode threshold relative to a specific WSPR SNR.
Calculations are based on mode sensitivity over simulated AWGN channels so ionospheric distortion is not taken into account. However, the chart can be used to estimate relative performance over quiet HF channels.
I use the chart to determine which modes might be workable over a real path base on received WSPR spots (see chart #2). It's also useful to estimate the amount of power needed to bring a modes sensitivity above it's minimum decode threshold to work a particular path.