The key to satcoms is team work, the more you have down (up to 4) the better the effect
- Enemies are only shown on the minimap when they are in friendlies' line of sight.
- The minimap is sweeped to reveal enemies
- The sweep will have an increased frequency
- The sweep will retain its increased frequency as well as show the direction enemies are facing
So it might not be worth putting it down as soon as you get one, ask your team if anyone else has one or just wait until a team mate puts one down so you can get more benefit from it.