Land radars:

    200 r - 800		where t = technology level
t = -----------		      r = range of the radar
      16 - r

         50  + t
r = 16 * -------
         200 + t

range| 4  |  5 |  6 |  7 |  8 |  9 | 10 | 11 | 12 | 13 | 14 |
-----+----+----+----+----+----+----+----+----+----+----+----+
techn| 0  |18.2|40.0|66.7| 100| 143| 200| 280| 400| 600|1000|

Fortresses:

Requires 7 guns. If less guns, divide range by (7 / #guns)

    200 r - 350		where t = technology level
t = -----------		      r = range of the fort
       7 - r

        50  + t
r = 7 * -------
        200 + t

range| 2  | 3  | 4  |  5 |  6 | 6.5|
-----+----+----+----+----+----+----+
techn|10.0|62.5| 150| 325| 850|1900|
