investigating In GM radar mode, angular velocity of the radar dish changes depending on AZ setting in DBS.

[WHOGX5]

In the GM radar video posted by Wags (linked below with timestamp), when he enters DBS mode the angular velocity of the radar dish changes depending on the azimuth setting. Or alternatively, the time required to perform a full scan is correct, but it's not proportional to the angular velocity in DBS.

It seems like the radar is moving relative to the zoom level of the FCR, rather than the actual azimuth setting. If you're in DBS A6, the angular velocity of the radar dish should be the same as in DBS A1, but the time it takes for a full scan should take longer as you're scanning a wider area. Therefore, in DBS A6 you should only see your radar image update during the very short time the radar dish passes the area you're looking at, and then you'd have to wait for the radar dish to rotate all the way to the gimbal before coming back and updating the area you're looking at again.

As you can see, when Wags enters DBS with the A6 setting, it takes the same amount of time for a full scan as it does in NORM A6, but instead of moving left to right +-60 degrees, it moves relative to the borders of the zoomed DBS mode, roughly +-10 degrees, yet a full scan takes the same amount of time as +-60. Thus it has a lower angular velocity compared to NORM. Then when Wags enters A3 you see the angular velocity increase, which it shouldn't, while the time required for a full scan decreases, which it should. Finally, as he enters A1 it speeds up even more to roughly the correct angular velocity.

EDIT: Also, I just noticed that the same issue applies when he decreases the range in DBS 2. The edges of the scan is still relative to the display even though the FOV narrows down, rather than being relative to the azimuth setting.

Timestamp at 7:26.

 

Edited October 19, 2021 by WHOGX5

[WHOGX5]

Trackfile. As you can see, everything works as it should in NORM. It's in EXP, DBS1 and DBS2 that issues start to arise.

A-G Radar - Angular Velocity.trk

[Frederf]

EXP DBS1 and DBS2 modes sweep only across the area of interest, limited by the A6/A3/A1 setting. When in DBS2 and A6 setting the antenna will not sweep the entire traverse of 120 degrees because most of the sweep will be outside the area of interest.

It's an older video (probably APG-68(V)1, green scale, solid crosshairs, introductory video for F-16C) but observe how the antenna quickly transits to the right and then slowly scans to the left covering only the patch despite being in "A6". It does not sweep fully side to side.

https://youtube.com/Aq5HXTGUHGI?t=381

[WHOGX5]

1 hour ago, Frederf said:

EXP DBS1 and DBS2 modes sweep only across the area of interest, limited by the A6/A3/A1 setting. When in DBS2 and A6 setting the antenna will not sweep the entire traverse of 120 degrees because most of the sweep will be outside the area of interest.

It's an older video (probably APG-68(V)1, green scale, solid crosshairs, introductory video for F-16C) but observe how the antenna quickly transits to the right and then slowly scans to the left covering only the patch despite being in "A6". It does not sweep fully side to side.

https://youtube.com/Aq5HXTGUHGI?t=381

Ah ok, I wasn't sure about that one. In either case, shouldn't the angular velocity of the radar dish still be constant? Because as it is right now, if I set my radar to either EXP, DBS1 or DBS2 and cycle through A1, A3 and A6, the time required for a full scan will increase and decrease, hence the angular velocity of the radar dish, even though it's covering the same area.

Edited October 20, 2021 by WHOGX5

[Harker]

Yeah, azimuth selection should not affect DBS, as DBS only scans the area of interest anyway. And from IRL videos, the update speed should more or less be what it is with A6 in DCS right now.