DAYLEET, on 09 January 2016 - 10:46 PM, said:
It would actually be a canon/lore element.
- The Short-Range Scanner Sweep "provides a MechWarrior with a two-kilometer sweep". (CBT Companion, pg. 237)
- The Long-Range Sensor Sweep "shows a 32 square kilometer map [a circle of radius 3.19 kilometers], usually relayed to the battle computer from satellites", and "enemy 'Mechs are usually displayed as well, but no detail can be obtained unless they are within two kilometers of the scanning 'Mech". (CBT Companion, pg. 237)
- Standard Jamming Gear "enables a MechWarrior to jam communications up to two kilometers away against any BattleMech currently targeted on the primary viewing screen". (CBT Companion, pg. 239)
- Communications equipment is capable of "direct point-to-point operational ranges (without bouncing) averaging 50 kilometers on the ground". (TechManual, pg. 212)
- The searchlight "can light up targets as far away as five kilometers". (TechManual, pg. 237)
Aside from that, the sensor rules in Tactical Operations (specifically, the Sensor Ranges Table on page 222) state that basic 'Mech Radar has a range of 720 meters (24 hexes) with no special effects from the target (outside of the presence of Stealth Armor, ECM, Null Sig, or CLPS), Beagle has a range of 1080 meters (36 hexes) and also experiences no special effects from the target (outside of the presence of Stealth Armor, ECM, Null Sig, or CLPS), while the other sensor types do experience special effects based on the target type - IR (900 meters/30 hexes) cannot detect targets that are not "hot", seismic (180 meters/6 hexes) cannot detect targets that are stationary or airborne or submerged, and MagScan (900 meters/30 hexes) cannot detect targets below 20 tons or occupying a Heavy Industrial Zone hex.
Of those, only MagScan is affected by target size - "for any unit from 80 to 100 tons, the range of the sensor is expanded for that unit(s) alone by 1 hex" and "nits that weigh less than 20 tons cannot be detected by a magscan sensor, including all infantry".
Also, 'Mech Radar cannot see through terrain (Hill Hexes) or through structures (Building Hexes & Castle Brian Hexes) - the effect is "if along LOS, sensor completely blocked". Also, lots of ground clutter (Heavy Woods/Jungle Hexes & Ultra Woods/Jungle Hexes) would reduce the effectiveness of 'Mech Radar (–1 or -2 hexes per range bracket per hex in LOS).
But, a stock LCT-1V Locust and a stock Daishi Prime at the same distance on a flat, featureless map would show up equally well on 'Mech Radar.
(And, if they were at the same point on the Heat Scale, both would show up equally well on IR. But, the Daishi's being over 80 tons would mean that it would show up a bit further out on MagScan (930 meters/31 hexes, versus 900 meters/30 hexes).)



























