Radar Scanner allows all towers within its radius to be able to detect and target camo bloons.
Official BTD5 description
Radar Scanner Icon
Radar Scanner is the second upgrade on the second path for the Monkey Village. It costs $1700 on Easy, $2000 Medium, $2160 on Hard and $2400 on Impoppable. It allows all the towers in its radius to detect and to attack camo bloons. It also increases the range of the Monkey Village.
Bloons TD Battles Mobile History Edit
Cost of Radar Scanner decreased ($2000 --> $1750)
Top from left to right: Radar Scanner with no path-1 upgrades, with Monkey Beacon, with Jungle Drums, with Monkey Town. Bottom: Radar Scanner with High Energy Beacon.
High Energy Beacons with this upgrade will be able to attack Camo Bloons. However, it will not allow other High Energy Beacons in its range to attack Camo Bloons.
This upgrade is much more expensive than the Sonar Beacon upgrade in BTD4 ($280), which also allows towers in range to pop Camo Bloons.
The only difference between the two upgrades is the price and the fact that Radar Scanner increases range, while the Sonar Beacon doesn't.
Oddly, a "village radar scanner" is mentioned in the description of stage 3-1 of Bloons Super Monkey 2, even though the actual radar scanner village isn't seen.
The icon is a enemy radar scanner used on military ships to track the enemy similar how the radar scanner works, letting other towers detect camo bloons.
Upgrades in the Bloons TD series Current Towers Former Towers