diff --git a/map65/libm65/q65b.f90 b/map65/libm65/q65b.f90
index 2f69d44b4..548fc84dc 100644
--- a/map65/libm65/q65b.f90
+++ b/map65/libm65/q65b.f90
@@ -123,7 +123,7 @@ subroutine q65b(nutc,nqd,fcenter,nfcal,nfsample,ikhz,mousedf,ntol,xpol,  &
   MHz=fcenter
   freq0=MHz + 0.001*ikhz
   if(nsnr0.gt.-99) then
-     nq65df=nint(1000*(0.001*k0*df+nkhz_center-48.0+1.000-1.27046-ikhz))
+     nq65df=nint(1000*(0.001*k0*df+nkhz_center-48.0+1.000-1.27046-ikhz))-nfcal
      if(nqd.eq.1) then
         write(line,1020) ikhz,nq65df,45*(ipol-1),nutc,xdt0,nsnr0,msg0(1:27),cq0
 1020    format('!',i3.3,i5,i4,i6.4,f5.1,i5,' : ',a27,a3)