**Option one:**
Launch the "Combat Ops – Arland" company.
If the "Antenna R 404" task (located on the signal hill) does not appear among the random missions to destroy the object, then restart the company (may require many restarts).
Complete the mission using TNT (it won't work).
After the antenna is destroyed, the red light will be on.
**Option two:**
Start Game Master - Arland.
Try to destroy "Antena R 404" only with TNT - you will understand that it is possible by placing 2 TNT in the middle of the antenna (only like this), it does not work from the ground (the amount of TNT is not important).
After the antenna is destroyed, the red light will be on
Try this with other destructible high-rise objects from the "Objects" group (lighting towers, radio masts).