|Figure 1. G7IZU Sporatic E Map|
The signal of KD5SSG observed at the same time is shown in Figure 2:
Figure 3. Ionospheric Sounder from Eglin AFB 40 Miles to the East
Note in particular the reflections recorded along the bottom most trace...the others above it are roundtrip reflections which usually indicates a strong reflection.
My QRSS grabber was active on 10m at this time and the map shown at wsprnet.org looked like this"
Figure 4. WSPR Spots Taken During the Es Opening
Putting it all together I think the broadening of KD5SSF's signal is caused by backscatter from an overhead Sporatic E cloud at a height of 100 km which is the average height of the E layer. Also, the ionogram trace is showing the Es activity. At least this is my guess at this time.
If you are close to a QRSS station and see a similar broadening it may be an indication that a Sporatic E layer is overhead.