diff --git a/eos/effects/ewtesteffectjam.py b/eos/effects/ewtesteffectjam.py
index 7c18b5682..de80978a4 100644
--- a/eos/effects/ewtesteffectjam.py
+++ b/eos/effects/ewtesteffectjam.py
@@ -2,5 +2,9 @@
 # Modules from group: ECM (44 of 44)
 # Drones named like: EC (3 of 3)
 type = "projected", "active"
-def handler(fit, container, context):
-    pass
+def handler(fit, module, context):
+    if "projected" in context:
+        # jam formula: 1 - (1- (jammer str/ship str))^(# of jam mods with same str))
+        strModifier = 1 - module.getModifiedItemAttr("scan{0}StrengthBonus".format(fit.scanType))/fit.scanStrength
+
+        fit.ecmProjectedStr *= strModifier
diff --git a/eos/effects/overloadselfecmstrenghtbonus.py b/eos/effects/overloadselfecmstrenghtbonus.py
index 1a475aba7..c7906e010 100644
--- a/eos/effects/overloadselfecmstrenghtbonus.py
+++ b/eos/effects/overloadselfecmstrenghtbonus.py
@@ -3,7 +3,8 @@
 # Modules from group: ECM Burst (7 of 7)
 type = "overheat"
 def handler(fit, module, context):
-    for scanType in ("Gravimetric", "Magnetometric", "Radar", "Ladar"):
-        module.boostItemAttr("scan{0}StrengthBonus".format(scanType),
-                             module.getModifiedItemAttr("overloadECMStrengthBonus"),
-                             stackingPenalties = True)
+    if "projected" not in context:
+        for scanType in ("Gravimetric", "Magnetometric", "Radar", "Ladar"):
+            module.boostItemAttr("scan{0}StrengthBonus".format(scanType),
+                                 module.getModifiedItemAttr("overloadECMStrengthBonus"),
+                                 stackingPenalties = True)
diff --git a/eos/saveddata/fit.py b/eos/saveddata/fit.py
index acafbcfb7..e2aaaa847 100644
--- a/eos/saveddata/fit.py
+++ b/eos/saveddata/fit.py
@@ -65,6 +65,7 @@ class Fit(object):
         self.boostsFits = set()
         self.gangBoosts = None
         self.timestamp = time.time()
+        self.ecmProjectedStr = 1
         self.build()
 
     @reconstructor
@@ -93,6 +94,7 @@ class Fit(object):
         self.fleet = None
         self.boostsFits = set()
         self.gangBoosts = None
+        self.ecmProjectedStr = 1
         self.extraAttributes = ModifiedAttributeDict(self)
         self.extraAttributes.original = self.EXTRA_ATTRIBUTES
         self.ship = Ship(db.getItem(self.shipID)) if self.shipID is not None else None
@@ -226,6 +228,10 @@ class Fit(object):
 
         return type
 
+    @property
+    def jamChance(self):
+        return (1-self.ecmProjectedStr)*100
+
     @property
     def alignTime(self):
         agility = self.ship.getModifiedItemAttr("agility")
@@ -269,6 +275,7 @@ class Fit(object):
         self.__capState = None
         self.__capUsed = None
         self.__capRecharge = None
+        self.ecmProjectedStr = 1
         del self.__calculatedTargets[:]
         del self.__extraDrains[:]
 
@@ -341,7 +348,7 @@ class Fit(object):
             else:
                 c = chain((self.character, self.ship), self.drones, self.boosters, self.appliedImplants, self.modules,
                           self.projectedDrones, self.projectedModules)
-            
+
             if self.gangBoosts is not None:
                 contextMap = {Skill: "skill",
                               Ship: "ship",
@@ -366,7 +373,7 @@ class Fit(object):
                                 effect.handler(self, thing, context)
                             except:
                                 pass
-                                
+
             for item in c:
                 # Registering the item about to affect the fit allows us to track "Affected By" relations correctly
                 if item is not None:
@@ -375,7 +382,7 @@ class Fit(object):
                     if forceProjected is True:
                         targetFit.register(item)
                         item.calculateModifiedAttributes(targetFit, runTime, True)
-            
+
         for fit in self.projectedFits:
             fit.calculateModifiedAttributes(self, withBoosters=withBoosters, dirtyStorage=dirtyStorage)
 
diff --git a/gui/builtinStatsViews/targetingMiscViewFull.py b/gui/builtinStatsViews/targetingMiscViewFull.py
index 6b61ace4b..78a7285b4 100644
--- a/gui/builtinStatsViews/targetingMiscViewFull.py
+++ b/gui/builtinStatsViews/targetingMiscViewFull.py
@@ -189,12 +189,15 @@ class TargetingMiscViewFull(StatsView):
                             right = "%s [%d]" % (size, radius)
                             lockTime += "%5s\t%s\n" % (left,right)
                         label.SetToolTip(wx.ToolTip(lockTime))
-                    elif labelName == "labelSensorStr":
-                        label.SetToolTip(wx.ToolTip("Type: %s - %.1f" % (fit.scanType, mainValue)))
                     elif labelName == "labelFullSigRadius":
                         label.SetToolTip(wx.ToolTip("Probe Size: %.3f" % (fit.probeSize or 0) ))
                     elif labelName == "labelFullWarpSpeed":
                         label.SetToolTip(wx.ToolTip("Max Warp Distance: %.1f AU" % fit.maxWarpDistance))
+                    elif labelName == "labelSensorStr":
+                        if fit.jamChance > 0:
+                           label.SetToolTip(wx.ToolTip("Type: %s\n%.1f%% Chance of Jam" % (fit.scanType, fit.jamChance)))
+                        else:
+                           label.SetToolTip(wx.ToolTip("Type: %s" % (fit.scanType)))
                     elif labelName == "labelFullAlignTime":
                         label.SetToolTip(wx.ToolTip("%.3f" % mainValue))
                     elif labelName == "labelFullCargo":
@@ -214,6 +217,14 @@ class TargetingMiscViewFull(StatsView):
                     label.SetToolTip(wx.ToolTip("Max Warp Distance: %.1f AU" % fit.maxWarpDistance))
                 else:
                     label.SetToolTip(wx.ToolTip(""))
+            elif labelName == "labelSensorStr":
+                if fit:
+                    if fit.jamChance > 0:
+                        label.SetToolTip(wx.ToolTip("Type: %s\n%.1f%% Chance of Jam" % (fit.scanType, fit.jamChance)))
+                    else:
+                        label.SetToolTip(wx.ToolTip("Type: %s" % (fit.scanType)))
+                else:
+                    label.SetToolTip(wx.ToolTip(""))
             elif labelName == "labelFullCargo":
                 if fit:
                     cachedCargo = self._cachedValues[counter]