--- a/lib/ft8/filt8.f90
+++ b/lib/ft8/filt8.f90
@@ -9,7 +9,7 @@ subroutine filt8(f0,nslots,width,wave)
equivalence (x,cx)
x=wave
- call four2a(x,NFFT,1,-1,0) !r2c
+ call four2a(cx,NFFT,1,-1,0) !r2c
df=12000.0/NFFT
fa=f0 - 0.5*6.25
fb=f0 + 7.5*6.25 + (nslots-1)*60.0