diff --git a/includes/powder.h b/includes/powder.h
index 77e7ca185..6eb2a7426 100644
--- a/includes/powder.h
+++ b/includes/powder.h
@@ -767,10 +767,11 @@ static int lolzrule[9][9] =
 	{0,1,0,0,0,0,0,1,0},
 	{0,1,0,0,0,0,0,1,0},
 };
-int portal[(int)(MAX_TEMP-73.15f)/100+2][8][80];
-float portaltemp[(int)(MAX_TEMP-73.15f)/100+2][8][80];
-int portalctype[(int)(MAX_TEMP-73.15f)/100+2][8][80];
-int wireless[(int)(MAX_TEMP-73.15f)/100+2][2];
+#define CHANNELS ((int)(MAX_TEMP-73.15f)/100+2)
+int portal[CHANNELS][8][80];
+float portaltemp[CHANNELS][8][80];
+int portalctype[CHANNELS][8][80];
+int wireless[CHANNELS][2];
 
 extern int isplayer;
 extern float player[27];
diff --git a/src/elements/prti.c b/src/elements/prti.c
index b25f7a3db..560ba8ca7 100644
--- a/src/elements/prti.c
+++ b/src/elements/prti.c
@@ -4,6 +4,8 @@ int update_PRTI(UPDATE_FUNC_ARGS) {
 	int r, nnx, rx, ry;
 	int count =0;
 	parts[i].tmp = (int)((parts[i].temp-73.15f)/100+1);
+	if (parts[i].tmp>=CHANNELS) parts[i].tmp = CHANNELS-1;
+	else if (parts[i].tmp<0) parts[i].tmp = 0;
 	for (rx=-1; rx<2; rx++)
 		for (ry=-1; ry<2; ry++)
 			if (x+rx>=0 && y+ry>0 && x+rx<XRES && y+ry<YRES && (rx || ry))
diff --git a/src/elements/prto.c b/src/elements/prto.c
index 2da6e0055..8f743e702 100644
--- a/src/elements/prto.c
+++ b/src/elements/prto.c
@@ -4,6 +4,8 @@ int update_PRTO(UPDATE_FUNC_ARGS) {
 	int r, nnx, rx, ry, np;
 	int count = 0;
 	parts[i].tmp = (int)((parts[i].temp-73.15f)/100+1);
+	if (parts[i].tmp>=CHANNELS) parts[i].tmp = CHANNELS-1;
+	else if (parts[i].tmp<0) parts[i].tmp = 0;
 	for (rx=-1; rx<2; rx++)
 		for (ry=-1; ry<2; ry++)
 			if (x+rx>=0 && y+ry>0 && x+rx<XRES && y+ry<YRES && (rx || ry))
diff --git a/src/elements/wifi.c b/src/elements/wifi.c
index fc5ee7f6c..a511e4b42 100644
--- a/src/elements/wifi.c
+++ b/src/elements/wifi.c
@@ -3,6 +3,8 @@
 int update_WIFI(UPDATE_FUNC_ARGS) {
 	int r, rx, ry;
 	parts[i].tmp = (int)((parts[i].temp-73.15f)/100+1);
+	if (parts[i].tmp>=CHANNELS) parts[i].tmp = CHANNELS-1;
+	else if (parts[i].tmp<0) parts[i].tmp = 0;
 	for (rx=-1; rx<2; rx++)
 		for (ry=-1; ry<2; ry++)
 			if (x+rx>=0 && y+ry>0 && x+rx<XRES && y+ry<YRES && (rx || ry))