diff --git a/boswatch/inputSource/sdrInput.py b/boswatch/inputSource/sdrInput.py
index 6b1faf7..cc4e64f 100644
--- a/boswatch/inputSource/sdrInput.py
+++ b/boswatch/inputSource/sdrInput.py
@@ -36,6 +36,8 @@ class SdrInput(InputBase):
             sdrProc.addArgument("-p " + str(sdrConfig.get("error", default="0")))      # frequency error in ppm
             sdrProc.addArgument("-l " + str(sdrConfig.get("squelch", default="1")))    # squelch
             sdrProc.addArgument("-g " + str(sdrConfig.get("gain", default="100")))     # gain
+            if (sdrConfig.get("fir_size") != None):
+                sdrProc.addArgument("-F " + str(sdrConfig.get("fir_size")))            # fir_size
             sdrProc.addArgument("-M fm")                                               # set mode to fm
             sdrProc.addArgument("-E DC")                                               # set DC filter
             sdrProc.addArgument("-s 22050")                                            # bit rate of audio stream
diff --git a/config/client.yaml b/config/client.yaml
index 1550eab..b6e2baf 100644
--- a/config/client.yaml
+++ b/config/client.yaml
@@ -26,6 +26,7 @@ inputSource:
     error: 0
     squelch: 1
     gain: 100
+    #fir_size: 0
     rtlPath: /usr/bin/rtl_fm
   lineIn:
     card: 1
diff --git a/docu/docs/changelog.md b/docu/docs/changelog.md
index 062b9cd..a022d4b 100644
--- a/docu/docs/changelog.md
+++ b/docu/docs/changelog.md
@@ -6,6 +6,7 @@
  * Divera24/7-Plugin
  * Python3-pip for requirements in install-script
  * Alsa-utils in install-script
+ * Add fir_size for RTL-FM as optionally value
 ### Changed
 ### Deprecated
 ### Removed