Scrambler is a Tier 3 perk appearing in Call of Duty: Modern Warfare 2 that scrambles the radar of nearby enemies, leaving only static. Enemies that are close to, but not entirely within, the scrambling radius will have their radar appear slightly fuzzy and faded. In multi-tiered structures, this can cause confusion to enemy players, allowing them to be picked off. The radar fading effects can also cover the location and direction of killstreaks, further benefiting the team. However, the perk is known to do more harm than good for the player, given the fact that an enemy player's radar fading out is a clear sign that an enemy is near, which can easily give away the player's position, or at least the player's presence.
The Pro version of this perk protects players from enemy Claymores by increasing the time between detection and detonation. This allows the user to slip past enemy claymores with ease, allowing the user to ambush the player who was using the claymores as a form of defense. However, with the radar fading effect of scrambler, and the claymore still giving the distinctive click, the player using Scrambler may find it more of a hindrance than a help. This effect can be useful in Hardcore Mode, as the lack of a HUD mini-map lowers the weakness of the radar-fading. This again, however, can be countered by players who check the overview map relatively often.
A player can distinguish between a Counter-UAV and a Scrambler user (other than hearing the announcer alert the team of a Counter-UAV) as Scrambler causes the radar to fade gradually depending on the distance between players, while a Counter-UAV cuts out the radar completely regardless of location. The two could be utilized together for great-effect. But overall, Scrambler is more of a hindrance than a useful perk when acting alone, as experienced players will be alerted to the player's presence upon seeing their radar turn fuzzy. Scrambler is unlocked at level 17. Scrambler Pro is unlocked by getting 50 close-range kills and the perk challenges are complete after 250 close-range kills.