Hi Guys,
I thought I must have missed this post first time round, but reading it now, I remember meaning to go back to it as I had initially read it on my phone and was somewhat confused as I couldn't make out the screengrab clearly. Much clearer now reading it on a big screen.
Firstly, the top two entries show PilotAware (PAW) signals not FLARM signals - the entry in the 'Mode' column is a 'P'. not an 'F' and the Squawk column for both clearly shows the default 'PAWGRP'.
Looking at the 2 entries for G-SOBI, they both have different Hex Addresses - the one for his Mode S transponder is correct for the aircraft, the PAW one looks like a system derived default - i.e. the hex address has not been set in the PAW configure screen - hence why you have two reports from the same aircraft.
So we have 2 entries for the same aircraft with differing altitudes - the PAW one (1225 feet) is GPS derived, whereas the Mode S one (1397 feet) is derived from the Barometric Sensor in the aircraft transponder and then compared with the barometric sensor on your PAW bridge. The difference (172 feet) would normally be due to known inaccuracies with GPS derived altitude compared to barometrically derived altitudes, though 172 feet appears to be a bigger difference than I would normally expect. It's possible that the barometric sensor in your colleague's plane is 'out' compared to the one in your test PAW, which would also account for this. The PAW (i.e.GPS) derived altitude of G-IRPW by the way is actually showing as -64, i.e. 64 feet below your test PAW in the club house. Would that be about right - seems a bit out to me. You can check your PAW barometric setting on the ground against the airfield reference pressure, provided both units are at the same actual altitude and you remember to check QNH against QNH, though looking at the entry for G-CGWD, which is reporting as 3 feet below your position in the clubhouse, I would suggest that your unit is probably about right on this occasion.
Regards
Peter