Observation 4547819: NOAA 9 (15427) - "strange" breaks in transmission?

Regarding Observation 4547819
The waterfall shows dark blue horizontal stripes - or is it the background showing with no signal present at that point?
This does not show on the waterfall of other recent satellite passes, only this one.
Does anyone know the cause, or hazard an informed guess, please?

My guess would be a strong out-of-band signal suppressing the gain of the LNA or SDR.


I have had stuff like this happen on my system (When it was working) when near by (ones I can hear on my HT) repeaters would key up on the 2m band.

Perhaps increasing the gain will help.
So more experimentation needed.
Many thanks for your comments.