diff --git a/doc/user_guide/en/images/misc-main-ui.png b/doc/user_guide/en/images/misc-main-ui.png
index 8ecd38131..267dca830 100644
Binary files a/doc/user_guide/en/images/misc-main-ui.png and b/doc/user_guide/en/images/misc-main-ui.png differ
diff --git a/lib/hspec.f90 b/lib/hspec.f90
index ed0541d61..4ede5060c 100644
--- a/lib/hspec.f90
+++ b/lib/hspec.f90
@@ -1,6 +1,6 @@
 subroutine hspec(id2,k,nutc0,ntrpdepth,nrxfreq,ntol,bmsk144,bcontest,  &
-     btrain,pcoeffs,ingain,mycall,hiscall,bshmsg,bswl,datadir,green,s,jh,pxmax,rmsNoGain,line1, &
-     mygrid)
+     btrain,pcoeffs,ingain,mycall,hiscall,bshmsg,bswl,datadir,green,s, &
+     jh,pxmax,dbNoGain,line1,mygrid)
 
 ! Input:
 !  k         pointer to the most recent new data
@@ -72,7 +72,7 @@ subroutine hspec(id2,k,nutc0,ntrpdepth,nrxfreq,ntol,bmsk144,bcontest,  &
      green(jh)=0.
      if(rms.gt.0.0) then
         green(jh)=20.0*log10(rms)
-        rmsNoGain=20.0*log10(rms2);
+        dbNoGain=20.0*log10(rms2);
      endif
      call four2a(x,nfft,1,-1,0)                   !Real-to-complex FFT
      df=12000.0/nfft
diff --git a/lib/symspec.f90 b/lib/symspec.f90
index d9df53a59..8135a8124 100644
--- a/lib/symspec.f90
+++ b/lib/symspec.f90
@@ -1,5 +1,5 @@
 subroutine symspec(shared_data,k,ntrperiod,nsps,ingain,nminw,pxdb,s,   &
-     df3,ihsym,npts8, rmsnogain, pxdbmax)
+     df3,ihsym,npts8,pxdbmax)
 
 ! Input:
 !  k         pointer to the most recent new data
@@ -10,7 +10,7 @@ subroutine symspec(shared_data,k,ntrperiod,nsps,ingain,nminw,pxdb,s,   &
 !  nbslider  NB setting, 0-100
 
 ! Output:
-!  pxdb      power (0-60 dB)
+!  pxdb      raw power (0-90 dB)
 !  s()       current spectrum for waterfall display
 !  ihsym     index number of this half-symbol (1-184) for 60 s modes
 
@@ -27,12 +27,11 @@ subroutine symspec(shared_data,k,ntrperiod,nsps,ingain,nminw,pxdb,s,   &
   real*4 ssum(NSMAX)
   real*4 xc(0:MAXFFT3-1)
   real*4 tmp(NSMAX)
-  real*4 rmsnogain
   complex cx(0:MAXFFT3/2)
   integer nch(7)
 
   common/spectra/syellow(NSMAX),ref(0:3456),filter(0:3456)
-  data rms/999.0/,k0/99999999/,nfft3z/0/
+  data k0/99999999/,nfft3z/0/
   data nch/1,2,4,9,18,36,72/
   equivalence (xc,cx)
   save
@@ -71,14 +70,10 @@ subroutine symspec(shared_data,k,ntrperiod,nsps,ingain,nminw,pxdb,s,   &
      if (abs(x1).gt.pxmax) pxmax = abs(x1);
      sq=sq + x1*x1
   enddo
-  rmsnogain = 0.
-  if (sq.gt.0.0) rmsnogain=20*log10(sqrt(sq/(k-k0)))
-  sq=sq * gain
-  rms=sqrt(sq/(k-k0))
-  pxdb=0.
-  pxdbmax = 20*log10(pxmax)
-  if(rms.gt.0.0) pxdb=20.0*log10(rms)
-  if(pxdb.gt.90.0) pxdb=90.0
+  pxdb = 0.
+  if(sq.gt.0.0) pxdb=10*log10(sq/(k-k0))
+  pxdbmax=0.
+  if(pxmax.gt.0) pxdbmax = 20*log10(pxmax)
 
   k0=k
   ja=ja+jstep                         !Index of first sample
diff --git a/mainwindow.cpp b/mainwindow.cpp
index 7b4e65d7b..0d97cacf5 100644
--- a/mainwindow.cpp
+++ b/mainwindow.cpp
@@ -66,7 +66,8 @@
 extern "C" {
   //----------------------------------------------------- C and Fortran routines
   void symspec_(struct dec_data *, int* k, int* ntrperiod, int* nsps, int* ingain,
-                int* minw, float* px, float s[], float* df3, int* nhsym, int* npts8, float *rmsnogain, float *m_pxmax);
+                int* minw, float* px, float s[], float* df3, int* nhsym, int* npts8,
+                float *m_pxmax);
 
   void hspec_(short int d2[], int* k, int* nutc0, int* ntrperiod, int* nrxfreq, int* ntol,
               bool* bmsk144, bool* bcontest, bool* btrain, double const pcoeffs[], int* ingain,
@@ -266,7 +267,6 @@ MainWindow::MainWindow(QDir const& temp_directory, bool multiple,
   m_ihsym {0},
   m_nzap {0},
   m_px {0.0},
-  m_rmsNoGain {0.0},
   m_iptt0 {0},
   m_btxok0 {false},
   m_nsendingsh {0},
@@ -1162,13 +1162,10 @@ void MainWindow::dataSink(qint64 frames)
   int nsps=m_nsps;
   if(m_bFastMode) nsps=6912;
   int nsmo=m_wideGraph->smoothYellow()-1;
-  symspec_(&dec_data,&k,&trmin,&nsps,&m_inGain,&nsmo,&m_px,s,&m_df3,&m_ihsym,&m_npts8,&m_rmsNoGain,&m_pxmax);
+  symspec_(&dec_data,&k,&trmin,&nsps,&m_inGain,&nsmo,&m_px,s,&m_df3,&m_ihsym,&m_npts8,&m_pxmax);
   if(m_mode=="WSPR") wspr_downsample_(dec_data.d2,&k);
   if(m_ihsym <=0) return;
-  QString t;
-  m_pctZap=m_nzap*100.0/m_nsps; // TODO: this is currently redundant
-  t.sprintf(" Rx noise: %5.1f ",m_px);
-  if (ui) ui->signal_meter_widget->setValue(m_rmsNoGain,m_pxmax); // Update thermometer
+  if(ui) ui->signal_meter_widget->setValue(m_px,m_pxmax); // Update thermometer
   if(m_monitoring || m_diskData) {
     m_wideGraph->dataSink2(s,m_df3,m_ihsym,m_diskData);
   }
diff --git a/mainwindow.h b/mainwindow.h
index cc69f36da..e08f00742 100644
--- a/mainwindow.h
+++ b/mainwindow.h
@@ -439,13 +439,11 @@ private:
   bool    m_bDoubleClicked;
   bool    m_bHideControls;
 
-  float   m_pctZap;
   int			m_ihsym;
   int			m_nzap;
   int			m_npts8;
   float		m_px;
-  float     m_pxmax;
-  float     m_rmsNoGain;
+  float   m_pxmax;
   float		m_df3;
   int			m_iptt0;
   bool		m_btxok0;