diff --git a/CMakeLists.txt b/CMakeLists.txt
index 825431d9e..8b4434ec0 100644
--- a/CMakeLists.txt
+++ b/CMakeLists.txt
@@ -743,9 +743,6 @@ qt5_use_modules (jt9 Core)
 
 if (${OPENMP_FOUND})
   add_executable (jt9_omp lib/jt9.f90 lib/jt9a.f90 lib/jt9b.f90 lib/jt9c.f90 ${jt9_CXXSRCS} wsjtx.rc)
-  if (WIN32)
-    set (_extra_omp_link_flags "-Wl,--stack,8388608")
-  endif (WIN32)
   set_target_properties (jt9_omp
     PROPERTIES
     COMPILE_FLAGS "${OpenMP_C_FLAGS}"
diff --git a/lib/downsam9.f90 b/lib/downsam9.f90
index c3169aaa8..d30d61577 100644
--- a/lib/downsam9.f90
+++ b/lib/downsam9.f90
@@ -1,93 +1,86 @@
-subroutine downsam9(id2,npts8,nsps8,newdat,nspsd,fpk,c2,nz2)
-
-!Downsample from id2() into c2() so as to yield nspsd samples per symbol, 
-!mixing from fpk down to zero frequency.  The downsample factor is 432.
-
-  use, intrinsic :: iso_c_binding
-  use FFTW3
-
-  include 'constants.f90'
-  parameter (NMAX1=604800)
-  type(C_PTR) :: plan                        !Pointers plan for big FFT
-  integer*2 id2(0:8*npts8-1)
-  real*4 x1(0:NMAX1-1)
-  complex c1(0:NMAX1/2)
-  complex c2(0:1440-1)
-  real s(5000)
-  logical first
-  common/patience/npatience,nthreads
-  data first/.true./
-  save plan,first,c1,s
-
-  nfft1=NMAX1                                !Forward FFT length
-  df1=12000.0/nfft1
-  npts=8*npts8
-
-  if(newdat.eq.1) then
-     fac=6.963e-6                            !Why this weird constant?
-     do i=0,npts-1
-        x1(i)=fac*id2(i)
-     enddo
-     x1(npts:nfft1-1)=0.                      !Zero the rest of x1
-  endif
-
-  if(first) then
-     nflags=FFTW_ESTIMATE
-     if(npatience.eq.1) nflags=FFTW_ESTIMATE_PATIENT
-     if(npatience.eq.2) nflags=FFTW_MEASURE
-     if(npatience.eq.3) nflags=FFTW_PATIENT
-     if(npatience.eq.4) nflags=FFTW_EXHAUSTIVE
-! Plan the FFTs just once
-
-     !$omp critical(fftw) ! serialize non thread-safe FFTW3 calls
-     call fftwf_plan_with_nthreads(nthreads)
-     plan=fftwf_plan_dft_r2c_1d(nfft1,x1,c1,nflags)
-     call fftwf_plan_with_nthreads(1)
-     !$omp end critical(fftw)
-
-     first=.false.
-  endif
-
-  if(newdat.eq.1) then
-     fac=6.963e-6                             !Why this weird constant?
-     do i=0,npts-1
-        x1(i)=fac*id2(i)
-     enddo
-     x1(npts:nfft1-1)=0.                      !Zero the rest of x1
-     call timer('FFTbig9 ',0)
-     call fftwf_execute_dft_r2c(plan,x1,c1)
-     call timer('FFTbig9 ',1)
-
-     nadd=int(1.0/df1)
-     s=0.
-     do i=1,5000
-        j=int((i-1)/df1)
-        do n=1,nadd
-           j=j+1
-           s(i)=s(i)+real(c1(j))**2 + aimag(c1(j))**2
-        enddo
-     enddo
-  endif
-
-  ndown=8*nsps8/nspsd                      !Downsample factor
-  nfft2=nfft1/ndown                        !Backward FFT length
-  nh2=nfft2/2
-  nf=nint(fpk)
-  i0=int(fpk/df1)
-
-  nw=100
-  ia=max(1,nf-nw)
-  ib=min(5000,nf+nw)
-  call pctile(s(ia),ib-ia+1,40,avenoise)
-
-  fac=sqrt(1.0/avenoise)
-  do i=0,nfft2-1
-     j=i0+i
-     if(i.gt.nh2) j=j-nfft2
-     c2(i)=fac*c1(j)
-  enddo
-  call four2a(c2,nfft2,1,1,1)              !FFT back to time domain
-  nz2=8*npts8/ndown
-
-  return
-end subroutine downsam9
+subroutine downsam9(id2,npts8,nsps8,newdat,nspsd,fpk,c2,nz2)
+
+!Downsample from id2() into c2() so as to yield nspsd samples per symbol, 
+!mixing from fpk down to zero frequency.  The downsample factor is 432.
+
+  use, intrinsic :: iso_c_binding
+  use FFTW3
+
+  include 'constants.f90'
+  parameter (NMAX1=604800)
+  type(C_PTR) :: plan                        !Pointers plan for big FFT
+  integer*2 id2(0:8*npts8-1)
+  real*4, pointer :: x1(:)
+  complex c1(0:NMAX1/2)
+  complex c2(0:1440-1)
+  real s(5000)
+  logical first
+  common/patience/npatience,nthreads
+  data first/.true./
+  save plan,first,c1,s,x1
+
+  nfft1=NMAX1                                !Forward FFT length
+  df1=12000.0/nfft1
+  npts=8*npts8
+
+  if(first) then
+     nflags=FFTW_ESTIMATE
+     if(npatience.eq.1) nflags=FFTW_ESTIMATE_PATIENT
+     if(npatience.eq.2) nflags=FFTW_MEASURE
+     if(npatience.eq.3) nflags=FFTW_PATIENT
+     if(npatience.eq.4) nflags=FFTW_EXHAUSTIVE
+! Plan the FFTs just once
+
+     !$omp critical(fftw) ! serialize non thread-safe FFTW3 calls
+     plan=fftwf_alloc_real(NMAX1)
+     call c_f_pointer(plan,x1,[NMAX1])
+     x1(0:NMAX1-1) => x1        !remap bounds
+     call fftwf_plan_with_nthreads(nthreads)
+     plan=fftwf_plan_dft_r2c_1d(nfft1,x1,c1,nflags)
+     call fftwf_plan_with_nthreads(1)
+     !$omp end critical(fftw)
+
+     first=.false.
+  endif
+
+  if(newdat.eq.1) then
+     fac=6.963e-6                             !Why this weird constant?
+     x1(0:npts-1)=fac*id2(0:npts-1)
+     x1(npts:nfft1-1)=0.                      !Zero the rest of x1
+     call timer('FFTbig9 ',0)
+     call fftwf_execute_dft_r2c(plan,x1,c1)
+     call timer('FFTbig9 ',1)
+
+     nadd=int(1.0/df1)
+     s=0.
+     do i=1,5000
+        j=int((i-1)/df1)
+        do n=1,nadd
+           j=j+1
+           s(i)=s(i)+real(c1(j))**2 + aimag(c1(j))**2
+        enddo
+     enddo
+  endif
+
+  ndown=8*nsps8/nspsd                      !Downsample factor
+  nfft2=nfft1/ndown                        !Backward FFT length
+  nh2=nfft2/2
+  nf=nint(fpk)
+  i0=int(fpk/df1)
+
+  nw=100
+  ia=max(1,nf-nw)
+  ib=min(5000,nf+nw)
+  call pctile(s(ia),ib-ia+1,40,avenoise)
+
+  fac=sqrt(1.0/avenoise)
+  do i=0,nfft2-1
+     j=i0+i
+     if(i.gt.nh2) j=j-nfft2
+     c2(i)=fac*c1(j)
+  enddo
+  call four2a(c2,nfft2,1,1,1)              !FFT back to time domain
+  nz2=8*npts8/ndown
+
+  return
+end subroutine downsam9