diff --git a/commons.h b/commons.h
index f53bfff99..140c69c6d 100644
--- a/commons.h
+++ b/commons.h
@@ -2,7 +2,7 @@
 #define COMMONS_H
 
 #define NSMAX 6827
-#define NTMAX 300
+#define NTMAX 30*60
 #define RX_SAMPLE_RATE 12000
 
 #ifdef __cplusplus
diff --git a/lib/constants.f90 b/lib/constants.f90
index ea872e8ad..36e81c77b 100644
--- a/lib/constants.f90
+++ b/lib/constants.f90
@@ -1,4 +1,4 @@
-  integer, parameter :: NTMAX=300
+  integer, parameter :: NTMAX=30*60
   integer, parameter :: NMAX=NTMAX*12000 !Total sample intervals (one minute)
   integer, parameter :: NDMAX=NTMAX*1500 !Sample intervals at 1500 Hz rate
   integer, parameter :: NSMAX=6827       !Max length of saved spectra