Markus Vester DF6NM successfully used the digital mode OPERA to send a 2.5 milliwatt signal on 2.4 GHz through the amateur radio transponder on the Es’hail-2 / QO-100 geostationary satellite.
Graham G0NBD writes about the contact on Digital Radio Groupsio.
On March 3, 2019, Markus started using 250 milliwatts on 2.4 GHz into a 60 cm dish pointing at Es’hail-2. The downlink signal was received via the AMSAT-UK and BATC 10 GHz WebSDR at Goonhilly in Cornwall by Peter Knol PA1SDB.
Markus then reduced power to just 2.5 milliwatts and the signal was still receiveable.
See Digital Radio Groupsio post at
https://digitalradio.groups.io/g/main/message/50861
OPERA was developed by Jose EA5HVK and can be downloaded from
https://rosmodem.wordpress.com/
Es’hail-2 / Qatar OSCAR-100 web receiver now live
https://amsat-uk.org/2019/02/10/qatar-oscar-100-web-receiver-now-live/