diff --git a/gui/src/index.html b/gui/src/index.html
index be0588ee..ec8976eb 100644
--- a/gui/src/index.html
+++ b/gui/src/index.html
@@ -746,11 +746,11 @@
 						<div class="card-body p-2">
 							<div class="progress mb-0" style="height: 15px;">
 								<div class="progress-bar progress-bar-striped bg-primary" id="rms_level" role="progressbar" style="width: 0%" aria-valuenow="0" aria-valuemin="0" aria-valuemax="100"></div>
-								<p class="justify-content-center d-flex position-absolute w-100">RX AUDIO LEVEL - not implemented yet</p>
+								<p class="justify-content-center d-flex position-absolute w-100">RX AUDIO LEVEL</p>
 							</div>
 							<div class="progress mb-0" style="height: 5px;">
-								<div class="progress-bar progress-bar-striped bg-warning" role="progressbar" style="width: 10%" aria-valuenow="10" aria-valuemin="0" aria-valuemax="100"></div>
-								<div class="progress-bar bg-success" role="progressbar" style="width: 80%" aria-valuenow="80" aria-valuemin="0" aria-valuemax="100"></div>
+								<div class="progress-bar progress-bar-striped bg-warning" role="progressbar" style="width: 1%" aria-valuenow="1" aria-valuemin="0" aria-valuemax="100"></div>
+								<div class="progress-bar bg-success" role="progressbar" style="width: 89%" aria-valuenow="89" aria-valuemin="0" aria-valuemax="100"></div>
 								<div class="progress-bar progress-bar-striped bg-danger" role="progressbar" style="width: 10%" aria-valuenow="10" aria-valuemin="0" aria-valuemax="100"></div>
 							</div>
 						</div>
diff --git a/tnc/modem.py b/tnc/modem.py
index 6d1c513b..a2eef5bf 100644
--- a/tnc/modem.py
+++ b/tnc/modem.py
@@ -843,6 +843,9 @@ class RF:
         # Initialize channel_busy_delay counter
         channel_busy_delay = 0
 
+        # Initialize rms counter
+        rms_counter = 0
+
         while True:
             # time.sleep(0.01)
             threading.Event().wait(0.01)
@@ -874,8 +877,12 @@ class RF:
 
                         # Calculate audio RMS
                         # https://stackoverflow.com/a/9763652
-                        d = np.frombuffer(self.fft_data, np.int16).astype(np.float)
-                        static.AUDIO_RMS = int(np.sqrt((d * d).sum() / len(d)))
+                        # calculate RMS every 150 cycles for reducing CPU load
+                        rms_counter += 1
+                        if rms_counter > 150:
+                            d = np.frombuffer(self.fft_data, np.int16).astype(np.float)
+                            static.AUDIO_RMS = int(np.sqrt((d * d).sum() / len(d)))
+                            rms_counter = 0
 
                     # Check for signals higher than average by checking for "100"
                     # If we have a signal, increment our channel_busy delay counter