Hi! I think that might be due to the mod author left the "energy_per_nearby_scan" unchanged, resulting a longer time to refresh the nearby scan.
In vanilla, the radar consumes 300 kW, and each time a nearby scan takes 250 kJ to accomplish, the refresh rate is 250 kJ/300 kW = 0.8333 seconds.
So with this mini radar, the new refresh time will be 250 kJ/75 kW = 3.333 seconds. This is why you see it constantly blackout and work again.
Since the mod is not updated recently, if you want to adjust it, add the line
miniRadar.energy_per_nearby_scan = 62.5 kJ
in the modpack filepath Mini-Radar_0.1.1\prototypes\mini-radar.lua