diff --git a/lib/fst4_decode.f90 b/lib/fst4_decode.f90
index e97d8f096..ba49fb54d 100644
--- a/lib/fst4_decode.f90
+++ b/lib/fst4_decode.f90
@@ -227,7 +227,7 @@ contains
       ndropmax=1
       single_decode=iand(nexp_decode,32).ne.0
       npct=0
-      nb=nexp_decode/256 - 2
+      nb=nexp_decode/256 - 3
       if(nb.ge.0) npct=nb
       inb1=20
       inb2=5
@@ -235,6 +235,8 @@ contains
          inb2=5                !Try NB = 0, 5, 10, 15, 20%
       else if(nb.eq.-2) then
          inb2=2                !Try NB = 0, 2, 4,... 20%
+      else if(nb.eq.-3) then
+         inb2=1                !Try NB = 0, 1, 2,... 20%
       else
          inb1=0                !Fixed NB value, 0 to 25%
          ipct(0)=npct
@@ -900,6 +902,6 @@ contains
       enddo
 
       return
-   end subroutine dopspread
+    end subroutine dopspread
 
 end module fst4_decode
diff --git a/widgets/mainwindow.cpp b/widgets/mainwindow.cpp
index 6d5b01e58..8df2966f1 100644
--- a/widgets/mainwindow.cpp
+++ b/widgets/mainwindow.cpp
@@ -3120,7 +3120,7 @@ void MainWindow::decode()                                       //decode()
   dec_data.params.nexp_decode = static_cast<int> (m_config.special_op_id());
   if(m_config.single_decode()) dec_data.params.nexp_decode += 32;
   if(m_config.enable_VHF_features()) dec_data.params.nexp_decode += 64;
-  if(m_mode.startsWith("FST4")) dec_data.params.nexp_decode += 256*(ui->sbNB->value()+2);
+  if(m_mode.startsWith("FST4")) dec_data.params.nexp_decode += 256*(ui->sbNB->value()+3);
 
   ::memcpy(dec_data.params.datetime, m_dateTime.toLatin1()+"    ", sizeof dec_data.params.datetime);
   ::memcpy(dec_data.params.mycall, (m_config.my_callsign()+"            ").toLatin1(), sizeof dec_data.params.mycall);
diff --git a/widgets/mainwindow.ui b/widgets/mainwindow.ui
index bf80c09ac..bf7ac9885 100644
--- a/widgets/mainwindow.ui
+++ b/widgets/mainwindow.ui
@@ -2471,7 +2471,7 @@ Yellow when too low</string>
          <string>NB  </string>
         </property>
         <property name="minimum">
-         <number>-2</number>
+         <number>-3</number>
         </property>
         <property name="maximum">
          <number>25</number>