TheSnark,
I set up a straight flying F5 again also at 2500ft (that's the altitude in the video,) and tailed it for 6 mins at a distance of ~4nm, but it couldn't pick up it up the radar, inverting caused it to appear immediately as shown. I closed to a distance of ~0.5nm over 3 mins again nothing coming up.
An extract from the manual about usage of the Radar: "The Sapphire needs three seconds to perform a full scan in search mode. When searching for targets, fly for 10-15 seconds in one direction to allow a thorough search of an illuminated volume of airspace." So I feel I was more than generous with the time given to find the target.
A lot of the posts previous state it's poor low level performance, so i tried at 10000ft with a distance of ~4nm, and it popped up immediately with me in correct orientation, I inverted but failed to pick it up this time, and also noticed considerably more ground clutter on the screen than at lower altitudes (I imagine it should have less clutter at higher altitudes?)
I tried again at 5000ft, again it was there without inverting and disappeared as I inverted.
4000ft the same, still there.
Then 3000ft I had the results as displayed in the video again, invisible to me till I'm upside down. I not sure what conclusions can be drawn from this, but these are simply my observations. This was all tested with the F5 only, so it could be an issue specifically related to that. However iirc when the F15 was present in front of me it too appeared as I inverted the Mig.