Hello Bruce
Nice to read of your experiments, and I look forward to seeing the results of your 50 microwatts and below transmissions.

The attachment is a screenshot of three plots from the WsprDaemon Grafana site showing time series of a) your SNR at N6GN/K (specifically at receiver GN2), your signal level in dBm, and the noise level at Glenn's GN2 receiver. Your signal level has been calculated from your SNR and the Noise level. This can be useful if the noise level changes between the times when you transmitting at different power levels.

The noise plot does allow you to check whether your surmise about atmospheric noise increasing being the cause of your spots not being heard is indeed true, or, as in the case with 20 m, the band closes to your signal, and to noise propagation.

I've sent you an email to your address on QRZ.com  with log on details for accessing this plot.

73
Gwyn G3ZIL