diff --git a/OpenRA.Mods.RA/Effects/Missile.cs b/OpenRA.Mods.RA/Effects/Missile.cs
index 88bedf524a..82af5b8151 100755
--- a/OpenRA.Mods.RA/Effects/Missile.cs
+++ b/OpenRA.Mods.RA/Effects/Missile.cs
@@ -41,8 +41,9 @@ namespace OpenRA.Mods.RA.Effects
 		public readonly Color ContrailColor = Color.White;
 		public readonly bool ContrailUsePlayerColor = false;
 		public readonly int ContrailDelay = 1;
+		public readonly bool Jammable = true;
 
-		public IEffect Create(ProjectileArgs args) { return new Missile( this, args ); }
+		public IEffect Create(ProjectileArgs args) { return new Missile(this, args); }
 	}
 
 	class Missile : IEffect
@@ -90,27 +91,44 @@ namespace OpenRA.Mods.RA.Effects
 		const int MissileCloseEnough = 7;
 		int ticksToNextSmoke;
 
-		public void Tick( World world )
+		public void Tick(World world)
 		{
 			t += 40;
 
 			// In pixels
 			var dist = Args.target.CenterLocation + offset - PxPosition;
 
-			var targetAltitude = 0;
+			var targetAltitude = 0; 
 			if (Args.target.IsValid && Args.target.IsActor && Args.target.Actor.HasTrait<IMove>())
-				targetAltitude =  Args.target.Actor.Trait<IMove>().Altitude;
+				targetAltitude = Args.target.Actor.Trait<IMove>().Altitude;
 
-			Altitude += Math.Sign(targetAltitude - Altitude);
+			var jammed = Info.Jammable && world.ActorsWithTrait<JamsMissiles>().Any(tp =>
+				(tp.Actor.CenterLocation - PxPosition).ToCVec().Length <= tp.Trait.Range
 
-			if (Args.target.IsValid)
+				&& (tp.Actor.Owner.Stances[Args.firedBy.Owner] != Stance.Ally
+				|| (tp.Actor.Owner.Stances[Args.firedBy.Owner] == Stance.Ally && tp.Trait.AlliedMissiles))
+
+				&& world.SharedRandom.Next(100 / tp.Trait.Chance) == 0);
+
+			if (!jammed)
+			{
+				Altitude += Math.Sign(targetAltitude - Altitude);
+				if (Args.target.IsValid)
+					Facing = Traits.Util.TickFacing(Facing,
+						Traits.Util.GetFacing(dist, Facing),
+						Info.ROT);
+			}
+			else
+			{
+				Altitude += world.SharedRandom.Next(-1, 2);
 				Facing = Traits.Util.TickFacing(Facing,
-					Traits.Util.GetFacing(dist, Facing),
+					Facing + world.SharedRandom.Next(-20, 21),
 					Info.ROT);
+			}
 
 			anim.Tick();
 
-			if (dist.LengthSquared < MissileCloseEnough * MissileCloseEnough && Args.target.IsValid )
+			if (dist.LengthSquared < MissileCloseEnough * MissileCloseEnough && Args.target.IsValid)
 				Explode(world);
 
 			// TODO: Replace this with a lookup table
diff --git a/OpenRA.Mods.RA/JamsMissiles.cs b/OpenRA.Mods.RA/JamsMissiles.cs
new file mode 100644
index 0000000000..0f04fdd1ef
--- /dev/null
+++ b/OpenRA.Mods.RA/JamsMissiles.cs
@@ -0,0 +1,35 @@
+#region Copyright & License Information
+/*
+ * Copyright 2007-2013 The OpenRA Developers (see AUTHORS)
+ * This file is part of OpenRA, which is free software. It is made
+ * available to you under the terms of the GNU General Public License
+ * as published by the Free Software Foundation. For more information,
+ * see COPYING.
+ */
+#endregion
+
+using OpenRA;
+using OpenRA.Traits;
+
+namespace OpenRA.Mods.RA
+{
+	class JamsMissilesInfo : ITraitInfo
+	{
+		public readonly int Range = 0;
+		public readonly bool AlliedMissiles = true;
+		public readonly int Chance = 100;
+
+		public object Create(ActorInitializer init) { return new JamsMissiles(this); }
+	}
+
+	class JamsMissiles
+	{
+		readonly JamsMissilesInfo info;
+
+		public int Range { get { return info.Range; } }
+		public bool AlliedMissiles { get { return info.AlliedMissiles; } }
+		public int Chance { get { return info.Chance; } }
+
+		public JamsMissiles(JamsMissilesInfo info) { this.info = info; }
+	}
+}
\ No newline at end of file
diff --git a/OpenRA.Mods.RA/OpenRA.Mods.RA.csproj b/OpenRA.Mods.RA/OpenRA.Mods.RA.csproj
index 7f6c9ee5d3..9af3413a88 100644
--- a/OpenRA.Mods.RA/OpenRA.Mods.RA.csproj
+++ b/OpenRA.Mods.RA/OpenRA.Mods.RA.csproj
@@ -1,4 +1,4 @@
-<?xml version="1.0" encoding="utf-8"?>
+<?xml version="1.0" encoding="utf-8"?>
 <Project ToolsVersion="4.0" DefaultTargets="Build" xmlns="http://schemas.microsoft.com/developer/msbuild/2003">
   <PropertyGroup>
     <Configuration Condition=" '$(Configuration)' == '' ">Debug</Configuration>
@@ -233,6 +233,7 @@
     <Compile Include="InfiltrateForSupportPower.cs" />
     <Compile Include="Invulnerable.cs" />
     <Compile Include="IronCurtainable.cs" />
+    <Compile Include="JamsMissiles.cs" />
     <Compile Include="LeavesHusk.cs" />
     <Compile Include="LightPaletteRotator.cs" />
     <Compile Include="LimitedAmmo.cs" />
@@ -301,6 +302,7 @@
     <Compile Include="RallyPoint.cs" />
     <Compile Include="Reloads.cs" />
     <Compile Include="RenderDetectionCircle.cs" />
+    <Compile Include="RenderJammerCircle.cs" />
     <Compile Include="RenderRangeCircle.cs" />
     <Compile Include="Render\RenderBuilding.cs" />
     <Compile Include="Render\RenderBuildingCharge.cs" />
diff --git a/OpenRA.Mods.RA/ProvidesRadar.cs b/OpenRA.Mods.RA/ProvidesRadar.cs
index 05be93ab1a..7ab699db49 100755
--- a/OpenRA.Mods.RA/ProvidesRadar.cs
+++ b/OpenRA.Mods.RA/ProvidesRadar.cs
@@ -26,14 +26,14 @@ namespace OpenRA.Mods.RA
 			// Check if powered
 			if (self.IsDisabled()) return false;
 
-			var isJammed = self.World.ActorsWithTrait<JamsRadar>().Any(a => self.Owner != a.Actor.Owner
-				&& (self.Location - a.Actor.Location).Length < a.Actor.Info.Traits.Get<JamsRadarInfo>().Range);
+			var isJammed = self.World.ActorsWithTrait<JamsRadar>().Any(a => a.Actor.Owner.Stances[self.Owner] != Stance.Ally
+				&& (self.Location - a.Actor.Location).Length <= a.Actor.Info.Traits.Get<JamsRadarInfo>().Range);
 
 			return !isJammed;
 		}
 	}
 
-	class JamsRadarInfo : TraitInfo<JamsRadar> { public readonly int Range = 0;	}
+	class JamsRadarInfo : TraitInfo<JamsRadar> { public readonly int Range = 0; }
 
 	class JamsRadar { }
 }
diff --git a/OpenRA.Mods.RA/RenderJammerCircle.cs b/OpenRA.Mods.RA/RenderJammerCircle.cs
new file mode 100644
index 0000000000..b70c985f92
--- /dev/null
+++ b/OpenRA.Mods.RA/RenderJammerCircle.cs
@@ -0,0 +1,63 @@
+#region Copyright & License Information
+/*
+ * Copyright 2007-2013 The OpenRA Developers (see AUTHORS)
+ * This file is part of OpenRA, which is free software. It is made
+ * available to you under the terms of the GNU General Public License
+ * as published by the Free Software Foundation. For more information,
+ * see COPYING.
+ */
+#endregion
+
+using System.Drawing;
+using OpenRA.Graphics;
+using OpenRA.Traits;
+
+namespace OpenRA.Mods.RA
+{
+	//todo: remove all the Render*Circle duplication
+	class RenderJammerCircleInfo : TraitInfo<RenderJammerCircle>, IPlaceBuildingDecoration
+	{
+		public void Render(WorldRenderer wr, World w, ActorInfo ai, PPos centerLocation)
+		{
+			var jamsMissiles = ai.Traits.GetOrDefault<JamsMissilesInfo>();
+			if (jamsMissiles != null)
+				RenderJammerCircle.DrawRangeCircle(wr, centerLocation.ToFloat2(), jamsMissiles.Range, Color.Red);
+
+			var jamsRadar = ai.Traits.GetOrDefault<JamsRadarInfo>();
+			if (jamsRadar != null)
+				RenderJammerCircle.DrawRangeCircle(wr, centerLocation.ToFloat2(), jamsRadar.Range, Color.Blue);
+
+			foreach (var a in w.ActorsWithTrait<RenderJammerCircle>())
+				if (a.Actor.Owner == a.Actor.World.LocalPlayer)
+					a.Trait.RenderBeforeWorld(wr, a.Actor);
+		}
+	}
+
+	public class RenderJammerCircle : IPreRenderSelection
+	{
+		public void RenderBeforeWorld(WorldRenderer wr, Actor self)
+		{
+			if (self.Owner != self.World.LocalPlayer)
+				return;
+
+			var jamsMissiles = self.Info.Traits.GetOrDefault<JamsMissilesInfo>();
+			if (jamsMissiles != null)
+				DrawRangeCircle(wr, self.CenterLocation.ToFloat2(), jamsMissiles.Range, Color.Red);
+
+			var jamsRadar = self.Info.Traits.GetOrDefault<JamsRadarInfo>();
+			if (jamsRadar != null)
+				DrawRangeCircle(wr, self.CenterLocation.ToFloat2(), jamsRadar.Range, Color.Blue);
+		}
+
+		public static void DrawRangeCircle(WorldRenderer wr, float2 location, int range, Color color)
+		{
+			wr.DrawRangeCircleWithContrast(
+				Color.FromArgb(128, color),
+				location,
+				range,
+				Color.FromArgb(96, Color.Black),
+				1);
+		}
+	}
+}
+
diff --git a/mods/ra/rules/vehicles.yaml b/mods/ra/rules/vehicles.yaml
index b937292539..d35f345e27 100644
--- a/mods/ra/rules/vehicles.yaml
+++ b/mods/ra/rules/vehicles.yaml
@@ -490,7 +490,7 @@ MGG:
 	Inherits: ^Vehicle
 	Buildable:
 		Queue: Vehicle
-		BuildPaletteOrder: 150
+		BuildPaletteOrder: 160
 		Prerequisites: atek
 		Owner: allies
 		Hotkey: y
@@ -537,11 +537,13 @@ MRJ:
 		Cost: 1000
 	Tooltip:
 		Name: Mobile Radar Jammer
-		Description: Unarmed
+		Description: Jams nearby enemy radar domes\nand deflects incoming missiles.\n  Unarmed
 	Buildable:
 		Queue: Vehicle
-		BuildPaletteOrder: 1000
-		Owner: None
+		BuildPaletteOrder: 150
+		Prerequisites: atek
+		Owner: allies
+		Hotkey: m
 	Health:
 		HP: 200
 	Armor:
@@ -558,6 +560,11 @@ MRJ:
 	Explodes:
 		Weapon: UnitExplodeSmall
 		EmptyWeapon: UnitExplodeSmall
+	JamsRadar:
+		Range: 15
+	JamsMissiles:
+		Range: 3
+	RenderJammerCircle:
 
 1TNK.Husk:
 	Inherits: ^Husk