diff --git a/fvn_fnlib/dbesin.f90 b/fvn_fnlib/dbesin.f90
index 9926b4e..ea59887 100644
--- a/fvn_fnlib/dbesin.f90
+++ b/fvn_fnlib/dbesin.f90
@@ -12,6 +12,8 @@ function dbesin(n,x,factor,big)
     ! big : a real that determine the threshold for taking anti overflow counter measure
     ! default value is 1e10
     !
+    ! 2009 : increasing factor defult value to 150
+    !
     real(dp_kind) :: dbesin
     integer :: n
     real(dp_kind) :: x
@@ -25,7 +27,7 @@ function dbesin(n,x,factor,big)
     real(dp_kind), external :: dbesi0,dbesi1
 
     ! Initialization of optional parameters
-    tfactor=40
+    tfactor=150
     if(present(factor)) tfactor=factor
     tbig=1e10
     if(present(big)) tbig=big
diff --git a/fvn_fnlib/dbesjn.f90 b/fvn_fnlib/dbesjn.f90
index e092866..afc184c 100644
--- a/fvn_fnlib/dbesjn.f90
+++ b/fvn_fnlib/dbesjn.f90
@@ -12,6 +12,8 @@ function dbesjn(n,x,factor,big)
     ! big : a real that determine the threshold for taking anti overflow counter measure
     ! default value is 1e10
     !
+    ! 2009 : increasing factor defult value to 150
+    !
     real(dp_kind) :: dbesjn
     integer :: n
     real(dp_kind) :: x
@@ -26,7 +28,7 @@ function dbesjn(n,x,factor,big)
     logical :: iseven
 
     ! Initialization of optional parameters
-    tfactor=40
+    tfactor=150
     if(present(factor)) tfactor=factor
     tbig=1d10
     if(present(big)) tbig=big