Antenna Elevation: STT angle vs Pattern angle

[Karon]

Hey there!

I'm jumping back in the rear seat after months and I noticed something about the antenna elevation. It may be a bug, or just me being dumb and missing something obvious.

Scenario:
- F-14 flying at 15,000ft;
- Contact I: flying 5 nm in front of the F-14, co-speed, at 18,000ft (+3,000ft);
- Contact II: flying 10 nm in front of the F-14, co-speed, at 21,000ft (+6,000ft);
- Radar set in PSRCH, 1 bar.

In Theory, the contacts should be visible using the same antenna elevation angle, which should be 5.6° (using maths). I tested it, and it works as expected. I set the elevation at 5.4° up, and I saw both of them on the DDD. See image below:

I then proceeded to switch the HCU to RDR and locked in PSTT. I expected a change, but the displayed antenna elevation angle became 3.3°. The Elevation indicator matches the value displayed on the TID.
See below:

Problem: 3.3° is too low to see the contacts. At 5 nm, the width of the volume should be, approximated via maths, ±0.6°. In fact, by adjusting the elevation to match such value, there are no returns on the DDD.

This is the same example above, in a short video (quick and dirty):

 

What am I missing?