Do you happen to know the appreviation at satradar24 for position reports?
It looks like they are currently only monitoring uplinks to aircraft. They have monitored downlinks from aircraft in the past but I'm not seeing any right now.
There is another website here that is monitoring downlinks. However it's of limited use as the messages quickly scroll off the screen and there is no way to search through them.
http://thebaldgeek.net:2880/ui/#!/4#%2F4There are many types of position reports, but the most common are ADS (to ATC) and FMS (to company).
eg:
20:11:26 27-06-19 AES:AAA326 GES:02 2 .N785AN ! B6 8 Flight AA36
F87AAA0036/YQXE2YA.ADS.N785AN07217F16F9F3488B8A5E9D0C041333DA08200D216C1F1C71C908874920B60F55554908801006267E5A0103
Basic_Report:
Lat = 47.1042 Long = -46.0634 Alt = 35000 feet. Time past the hour = 11m 04s FOM = 1D
Flight ID AAL36
Next waypoint Lat = 47 Long = -40 Alt = 37000 feet. ETA = 00:31:05
Wind speed = 6 knots. True wind direction = 216 deg. Temperature = -52.75 deg C.
19:49:43 27-06-19 AES:4CA9DF GES:02 2 .EI-EJL ! B6 1 Flight AZ63C
J66AAZ063C/NYCODYA.ADS.EI-EJL14182846AACB09086E401D0D1993BEE39CC9088E3C1AFFBF1C7D490880E623
Waypoint_Change_Event:
Lat = 33.9711 Long = -59.9778 Alt = 36996 feet. Time past the hour = 49m 20s FOM = 1D
Next waypoint Lat = 35.9677 Long = -49.99 Alt = 37000 feet. ETA = 01:00:44
19:54:50 27-06-19 AES:AB2AD8 GES:02 2 .N819AN ! H1 4 Flight AA945
F23AAA0945#M2BPOSN24275W091246,DUTNA,024938,370,ODKOT,025117,AGPOD,M48,31615,1006/TS024938,28061998B8