diff --git a/lib/determ.f90 b/lib/determ.f90
new file mode 100644
index 000000000..6ae471bd3
--- /dev/null
+++ b/lib/determ.f90
@@ -0,0 +1,32 @@
+real*8 function determ(array,norder)
+  implicit real*8 (a-h,o-z)
+  real*8 array(10,10)
+
+  determ=1.
+  do k=1,norder
+     if (array(k,k).ne.0) go to 41
+     do j=k,norder
+        if(array(k,j).ne.0) go to 31
+     enddo
+     determ=0.
+     go to 60
+
+31   do i=k,norder
+        s8=array(i,j)
+        array(i,j)=array(i,k)
+        array(i,k)=s8
+     enddo
+     determ=-1.*determ
+41   determ=determ*array(k,k)
+     if(k.lt.norder) then
+        k1=k+1
+        do i=k1,norder
+           do j=k1,norder
+              array(i,j)=array(i,j)-array(i,k)*array(k,j)/array(k,k)
+           enddo
+        enddo
+     end if
+  enddo
+
+60 return
+end function determ
diff --git a/lib/flat3.f90 b/lib/flat3.f90
new file mode 100644
index 000000000..8255fca5c
--- /dev/null
+++ b/lib/flat3.f90
@@ -0,0 +1,74 @@
+subroutine flat3(savg0,iz,nterms,ynoise,savg)
+
+  implicit real*8 (a-h,o-z)
+  parameter (NSMAX=6827)
+  real*4 savg0(iz)
+  real*4 savg(iz)
+  real*4 ynoise,y4
+
+  real*8 x(NSMAX)
+  real*8 y(NSMAX)
+  real*8 y0(NSMAX)
+  real*8 yfit(NSMAX)
+  real*8 a(10)
+  integer ii(NSMAX)
+
+  npts0=999999
+  df=12000.0/16384.0
+
+  do i=1,iz
+     y0(i)=db(savg0(i))
+  enddo
+  ia=200.0/df
+  ib=4500.0/df
+  j=0
+  do i=ia,ib
+     j=j+1
+     x(j)=i*df
+     y(j)=y0(i)
+     ii(j)=i
+  enddo
+
+  npts=j
+  mode=0
+  a=0.0
+
+  do iter=1,99
+     call polfit(x,y,y,npts,nterms,mode,a,chisqr)
+!     print*,iter,npts,a(1:nterms)
+
+     rewind 21
+     do i=1,ib
+        f=i*df
+        yfit(i)=0.0
+        do n=1,nterms
+           yfit(i)=yfit(i) + a(n) * f**(n-1)
+        enddo
+!        write(21,1010) f,y0(i),yfit(i),y0(i)-yfit(i)
+!1010    format(4f12.3)
+     enddo
+     k=0
+     do j=1,npts
+        y1=y(j)-yfit(ii(j))
+        if(y1.lt.ynoise) then
+           k=k+1
+           x(k)=x(j)
+           y(k)=y(j)
+           ii(k)=ii(j)
+        endif
+     enddo
+     npts=k
+     if(npts.eq.npts0 .or. npts.lt.(ib-ia)/10) exit
+     npts0=npts
+  enddo
+
+!  do j=1,npts
+!     write(22,1010) x(j),y(j),yfit(ii(j)),y(j)-yfit(ii(j))
+!  enddo
+
+  do i=1,ib
+     y4=y0(i)-yfit(i)
+     savg(i)=10.0**(0.1*y4)
+  enddo
+
+end subroutine flat3
diff --git a/lib/polfit.f90 b/lib/polfit.f90
new file mode 100644
index 000000000..ea7ffc9f6
--- /dev/null
+++ b/lib/polfit.f90
@@ -0,0 +1,72 @@
+subroutine polfit(x,y,sigmay,npts,nterms,mode,a,chisqr)
+  implicit real*8 (a-h,o-z)
+  real*8 x(npts), y(npts), sigmay(npts), a(nterms)
+  real*8 sumx(19), sumy(10), array(10,10)
+
+! Accumulate weighted sums
+  nmax = 2*nterms-1
+  sumx=0.
+  sumy=0.
+  chisq=0.
+  do i=1,npts
+     xi=x(i)
+     yi=y(i)
+     if(mode.lt.0) then
+        weight=1./abs(yi)
+     else if(mode.eq.0) then
+        weight=1
+     else
+        weight=1./sigmay(i)**2
+     end if
+     xterm=weight
+     do n=1,nmax
+        sumx(n)=sumx(n)+xterm
+        xterm=xterm*xi
+     enddo
+     yterm=weight*yi
+     do n=1,nterms
+        sumy(n)=sumy(n)+yterm
+        yterm=yterm*xi
+     enddo
+     chisq=chisq+weight*yi**2
+  enddo
+
+! Construct matrices and calculate coefficients
+  do j=1,nterms
+     do k=1,nterms
+        n=j+k-1
+        array(j,k)=sumx(n)
+     enddo
+  enddo
+
+  delta=determ(array,nterms)
+  if(delta.eq.0) then
+     chisqr=0.
+     a=0.
+  else
+     do l=1,nterms
+        do j=1,nterms
+           do k=1,nterms
+              n=j+k-1
+              array(j,k)=sumx(n)
+           enddo
+           array(j,l)=sumy(j)
+        enddo
+        a(l)=determ(array,nterms)/delta
+     enddo
+
+! Calculate chi square
+
+     do j=1,nterms
+        chisq=chisq-2*a(j)*sumy(j)
+        do k=1,nterms
+           n=j+k-1
+           chisq=chisq+a(j)*a(k)*sumx(n)
+        enddo
+     enddo
+     free=npts-nterms
+     chisqr=chisq/free
+  end if
+  
+  return
+end subroutine polfit
diff --git a/lib/symspec.f90 b/lib/symspec.f90
index 2facb4903..a08e3c1a7 100644
--- a/lib/symspec.f90
+++ b/lib/symspec.f90
@@ -40,7 +40,8 @@ subroutine symspec(k,ntrperiod,nsps,ingain,slope,pxdb,s,df3,ihsym,npts8)
      go to 900                                 !Wait for enough samples to start
   endif
 
-  if(nfft3.ne.nfft3z .or. slope.ne.slope0) then    !New nfft3, compute window
+  if(nfft3.ne.nfft3z .or. (slope.ne.slope0 .and. abs(slope+0.1).gt.0.05)) then
+! Compute new window and adjust scale factor
      pi=4.0*atan(1.0)
      do i=1,nfft3
         w3(i)=2.0*(sin(i*pi/nfft3))**2         !Window for nfft3 spectrum
@@ -103,10 +104,14 @@ subroutine symspec(k,ntrperiod,nsps,ingain,slope,pxdb,s,df3,ihsym,npts8)
      s(i)=gain*sx
   enddo
 
-!  s=0.05*s/ref
   s=scale*s
   savg=scale*ssum/ihsym
 
+  if(abs(slope+0.1).lt.0.01) then
+     call flat3(s,iz,3,1.0,s)
+     call flat3(savg,iz,3,1.0,savg)
+  endif
+
 900 npts8=k/8
 
   return
diff --git a/wsjtx.pro b/wsjtx.pro
index 69ff9ece2..418c2e5d7 100644
--- a/wsjtx.pro
+++ b/wsjtx.pro
@@ -7,7 +7,7 @@
 QT       += network multimedia
 greaterThan(QT_MAJOR_VERSION, 4): QT += widgets
 CONFIG   += thread
-CONFIG   += console
+#CONFIG   += console
 
 TARGET = wsjtx
 #DESTDIR = ../qt4_install