Currently, default Demon radar range settings is 10NMi/19Km with next ranges 50NMi/93Km, 100NMi/185Km and 200NMi/370Km.
This is not very effective setting as 10NMi does not effectively use the useful range of the radar and 50NMi is roughly double the effective range and therefore sacrifices some range resolution as only lower half of display shows useful information.
100/200NMi are just useless options that you need to cycle trough when wanting to select appropriate range. They are in any aircraft given the size of map, but I understand F-4 and F14 have them for historical/realism purposes even if it is counterproductive for player (who has only one key for cycling ranges unlike pilot in cokpit). It does not make sense with Demon with much smaller radar at all, correct me if I am wrong. It’s not easy to find these data on F3, but I would vote for getting rid of them here.
More importantly, the Demon has range gap in between 10 and 50NMi unlike F-14 with 20NMi/37Km or F-4 with 25NMi/46Km. These are exactly the ranges that are most useful for Demon as they best use it’s effective detection range.
Data for F-4 and F-14 ranges were taken from DCS Heatblur manuals for respective aircraft as they worked closely with SMEs to model the aircraft. Matches my IRIAF F-14A in WT.
All in all, in Demon I need to regularly switch in between two sub-optimal ranges and cycle through some more utterly useless ranges in the process.
I would recommend ranges 5NMi for ACM, then 10NMi, 25NMi for SRC in Demon although I do not have data to back it up. Eventually 10, 20, 50NMi would work as well.