overshoot.patch

--- wsjtx/lib/fst4_decode.f90	2023-11-25 21:51:35.906349879 -0500
+++ wsjtx/lib/fst4_decode.f90	2023-11-25 21:51:20.415211696 -0500
@@ -988,13 +988,13 @@
       do i=-ia,ia                !Find freq range that has 50% of signal power
          sum2=sum2 + ss(i)-avg
          if(sum2.ge.0.25*sum1 .and. xi1.eq.-999.0) then
-            xi1=i - 1 + (sum2-0.25*sum1)/(sum2-sum2z)
+            xi1=i - 1 + (0.25*sum1-sum2)/(sum2-sum2z)
          endif
          if(sum2.ge.0.50*sum1 .and. xi2.eq.-999.0) then
-            xi2=i - 1 + (sum2-0.50*sum1)/(sum2-sum2z)
+            xi2=i - 1 + (0.50*sum1-sum2)/(sum2-sum2z)
          endif
          if(sum2.ge.0.75*sum1) then
-            xi3=i - 1 + (sum2-0.75*sum1)/(sum2-sum2z)
+            xi3=i - 1 + (0.75*sum1-sum2)/(sum2-sum2z)
             exit
          endif
          sum2z=sum2