diff --git a/contest/models.py b/contest/models.py
index 30319e8..9802c81 100644
--- a/contest/models.py
+++ b/contest/models.py
@@ -148,7 +148,7 @@ class QSO(models.Model):
 
 	cfmdQSO = models.ForeignKey("QSO", models.SET_NULL, null=True, blank=True, default=None)
 
-	CFMD_SEC = 300
+	CFMD_SEC = 5*60
 
 	def checkQSOData(self):
 		""" Match strdata to log rows. Only call, if you intent to save this object if we return True! """
@@ -182,8 +182,9 @@ class QSO(models.Model):
 		if self.cfmdQSO:
 			# check if this still checks out
 			q = self.cfmdQSO
-			if (self.time - q.time).total_seconds() <= self.CFMD_SEC and \
-				self.ref and self.owner.ref and \
+			if abs((self.time - q.time).total_seconds()) <= self.CFMD_SEC and \
+				self.ref and self.owner.ref and self.callRef and q.callRef and \
+				q.owner == self.callRef and q.callRef == self.owner and \
 				self.ref == q.owner.ref and self.owner.ref == q.ref and \
 				self.band == q.band:
 				# checks out
@@ -191,12 +192,15 @@ class QSO(models.Model):
 			else:
 				changed = True
 				self.cfmdQSO.cfmdQSO = None
+				self.cfmdQSO.save(checkQSO=False)
 				self.cfmdQSO = None
 
 		if self.ref and self.callRef and self.callRef.ref and not self.cfmdQSO:
 			# look for a matching line
 			q = QSO.objects.filter(
-				(Q(time__gte=self.time + datetime.timedelta(0, self.CFMD_SEC)) | Q(time__gte=self.time - datetime.timedelta(0, self.CFMD_SEC))),
+				(Q(time__lte=self.time + datetime.timedelta(seconds=self.CFMD_SEC)) & Q(time__gte=self.time - datetime.timedelta(seconds=self.CFMD_SEC))),
+				owner=self.callRef,
+				callRef=self.owner,
 				owner__ref=self.ref,
 				ref=self.owner.ref,
 				band=self.band)