diff --git a/lib/fst240/fst240sim.f90 b/lib/fst240/fst240sim.f90
index edf4fb44c..cdfc4e561 100644
--- a/lib/fst240/fst240sim.f90
+++ b/lib/fst240/fst240sim.f90
@@ -52,8 +52,8 @@ program fst240sim
    if(nsec.eq.60) nsps=3888
    if(nsec.eq.120) nsps=8200
    if(nsec.eq.300) nsps=21504
-   if(nsec.eq.900) nsps=65536
-   if(nsec.eq.1800) nsps=131072
+   if(nsec.eq.900) nsps=66560
+   if(nsec.eq.1800) nsps=134400
    if(nsps.eq.0) then
       print*,'Invalid TR sequence length.'
       go to 999
diff --git a/lib/fst240_decode.f90 b/lib/fst240_decode.f90
index cce63ab02..5976f63ad 100644
--- a/lib/fst240_decode.f90
+++ b/lib/fst240_decode.f90
@@ -202,14 +202,14 @@ contains
          ndown=512/hmod !nss=42,84,168,336
          nfft1=int((nmax-200)/ndown)*ndown
       else if(ntrperiod.eq.900) then
-         nsps=65536
+         nsps=66560
          nmax=900*12000
-         ndown=1024/hmod !nss=64,128,256,512
+         ndown=1664/hmod !nss=40,80,160,320
          nfft1=int((nmax-200)/ndown)*ndown
       else if(ntrperiod.eq.1800) then
-         nsps=131072
+         nsps=134400
          nmax=1800*12000
-         ndown=2048/hmod !nss=64,128,256,512
+         ndown=3360/hmod !nss=40,80,160,320
          nfft1=int((nmax-200)/ndown)*ndown
       end if
       nss=nsps/ndown