Would be interesting to see an analysis over a couple of hours in airplane mode.
I don't really understand why they only measured with the door open and then didn't test the difference with the door closed.
In either case, a good read.
Researchers at Trinity College Dublin, lead by Professor Doug Leith did a report to determine if Airplane Mode in #GrapheneOS and other devices actually disabled cellular. It doesnt have any cellular transmissions.
https://www.scss.tcd.ie/Doug.Leith/pubs/airplane_mode_report.pdf
There is a radio activity spike at the 2.4GHz band, this suggests Wi-Fi activity and is different from cellular network activity.
All credit to Doug here: https://www.scss.tcd.ie/Doug.Leith/
Discussion
I'm fine with them measuring longer periods of time including over a day. I assume they have other work taking their attention as they are a professor, but I openly invite them or anyone else with the facilities to do the same.