diff --git a/RELEASE_NOTES b/RELEASE_NOTES
index 554bb8b70..c3ca9b996 100644
--- a/RELEASE_NOTES
+++ b/RELEASE_NOTES
@@ -29,6 +29,7 @@ since ns-3.10, in many cases referencing the Bugzilla bug number.
 
    - Fixed the UanPhyGen::IsStateBusy method, error with logical OR
    - CsmaNetDevice ReceiveErrorModel was not dropping the packet
+   - bug 1064 - Correct Friis propagation loss equation in spectrum module
 
 Known issues
 ------------
diff --git a/src/spectrum/model/friis-spectrum-propagation-loss.cc b/src/spectrum/model/friis-spectrum-propagation-loss.cc
index 6b61c53f4..9c4cc5896 100644
--- a/src/spectrum/model/friis-spectrum-propagation-loss.cc
+++ b/src/spectrum/model/friis-spectrum-propagation-loss.cc
@@ -86,7 +86,8 @@ FriisSpectrumPropagationLossModel::CalculateLoss (double f, double d) const
     }
 
   NS_ASSERT (f > 0);
-  double loss = ( d * f * f) / ((3e8 * 3e8) / (4 * M_PI)) ;
+  double loss_sqrt = (4 * M_PI * f * d) / 3e8;
+  double loss = loss_sqrt * loss_sqrt;
 
   if (loss < 1)
     {
diff --git a/src/spectrum/model/friis-spectrum-propagation-loss.h b/src/spectrum/model/friis-spectrum-propagation-loss.h
index ca321eb9d..343ecdc64 100644
--- a/src/spectrum/model/friis-spectrum-propagation-loss.h
+++ b/src/spectrum/model/friis-spectrum-propagation-loss.h
@@ -49,7 +49,7 @@ public:
    * Return the propagation loss L according to a simplified version of Friis'
    * formula in which antenna gains are unitary:
    *
-   *         4 * pi * d * f^2
+   *      (4 * pi * d * f) ^ 2
    * L = ----------------------
    *               C^2
    *