diff --git a/tools/pos2aprs.pl b/tools/pos2aprs.pl
index 33d95ce..33ea005 100755
--- a/tools/pos2aprs.pl
+++ b/tools/pos2aprs.pl
@@ -34,7 +34,7 @@ my $line;
 
 my $hms;
 my $lat; my $lon; my $alt;
-my $sign;
+my $sign = 1;
 my $NS; my $EW;
 my $str;
 
diff --git a/tools/pos2nmea.pl b/tools/pos2nmea.pl
index 2cf438f..96dcc09 100755
--- a/tools/pos2nmea.pl
+++ b/tools/pos2nmea.pl
@@ -34,7 +34,7 @@ my $line;
 
 my $hms;
 my $lat; my $lon; my $alt;
-my $sign;
+my $sign = 1;
 my $NS; my $EW;
 my $cs;
 my $str;