The fact is that for a primary radar the range limit will be about equal to the horizon. Factoring in a target altitude and the radar antenna elevation this will work out to something like 200 miles, probably a little more in practice. (The limitation of a radar's range will not be transmit power or receiver sensitivity, as even late 20th century technology has provided ample capability there.)
The detection range of a primary radar is dictated by the pulse repetition frequency - although ground clutter and the physical horizon limit the range at low elevations. A typical PRF for weather radar for example is 400 hz, supporting ranges up to 300 miles or more.
A military radar would use a low PRF for scanning, but would need to switch to a higher PRF for target acquisition and launch that would limit the range to about 90 miles or even less. I expect that is the "implied threat" in Indonesia's claim of a radar range of only 90 miles.