diff --git a/files/etc/crontabs/root b/files/etc/crontabs/root
index 756221ae..0293c59c 100644
--- a/files/etc/crontabs/root
+++ b/files/etc/crontabs/root
@@ -1,4 +1,5 @@
 */5 * * * * /usr/local/bin/fccid
 * * * * * /usr/local/bin/rssi_monitor
 * * * * * /usr/local/bin/snrlog
+* * * * * /usr/local/bin/clean_zombie.sh
 
diff --git a/files/usr/local/bin/clean_zombie.sh b/files/usr/local/bin/clean_zombie.sh
new file mode 100755
index 00000000..f30935a7
--- /dev/null
+++ b/files/usr/local/bin/clean_zombie.sh
@@ -0,0 +1,71 @@
+#!/bin/sh
+<<'LICENSE'
+  Part of AREDN -- Used for creating Amateur Radio Emergency Data Networks
+  Copyright (C) 2018 Joe Ayers AE6XE
+  See Contributors file for additional contributors
+
+  This program is free software: you can redistribute it and/or modify
+  it under the terms of the GNU General Public License as published by
+  the Free Software Foundation version 3 of the License.
+
+  This program is distributed in the hope that it will be useful,
+  but WITHOUT ANY WARRANTY; without even the implied warranty of
+  MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+  GNU General Public License for more details.
+
+  You should have received a copy of the GNU General Public License
+  along with this program.  If not, see <http://www.gnu.org/licenses/>.
+
+  Additional Terms:
+
+  Additional use restrictions exist on the AREDN(TM) trademark and logo.
+    See AREDNLicense.txt for more info.
+
+  Attributions to the AREDN Project must be retained in the source code.
+  If importing this code into a new or existing project attribution
+  to the AREDN project must be added to the source code.
+
+  You must not misrepresent the origin of the material contained within.
+
+  Modified versions must be modified to attribute to the original source
+  and be marked in reasonable ways as differentiate it from the original
+  version.
+
+LICENSE
+
+# Look for hung 'iw' zombie processes prone to hang 
+# when available memory is low. 
+
+# wait for rssi_monitor and snrlog to run
+sleep 10
+
+for pid in `ps 2>/dev/null | egrep "^\s*\d+\s+root\s+\d+\s+Z\s+\[iw\]"| sed -e "s/^\s*//"| cut -f1 -d\ `
+do
+
+  # found an "iw" zombie
+  sleep 10 # give time in case process is naturally closing and needs more time
+  if [ -d /proc/$pid ] ; then
+    date >> /tmp/zombie.log
+    ps | egrep "^\s*${pid}" | grep -v grep | tail -1 >> /tmp/zombie.log
+    ppid=`cat /proc/$pid/status | grep -i ppid | cut -f2`
+    if [ -d /proc/$ppid ] ; then
+      ps | egrep "\s*${ppid}" | grep -v grep | tail -1 >> /tmp/zombie.log
+      if ( ! `grep crond /proc/$ppid/status 2>&1 > /dev/null` ) then
+        if [ $ppid -gt 1 ] ; then 
+
+          # kill the zombie's parent process to free up resources
+          kill -9 $ppid 2>&1 >> /tmp/zombie.log
+          echo "Killed $ppid" >> /tmp/zombie.log
+          if [ `wc -l /tmp/zombie.log | cut -f1 -d\ ` -gt 100 ] ; then
+
+            # keep file size in check
+            cp /tmp/zombie.log /tmp/zombie.tmp
+            tail -80 /tmp/zombie.tmp > /tmp/zombie.log
+            rm -f /tmp/zombie.tmp
+          fi
+        fi
+      fi
+    fi
+    echo "" >> /tmp/zombie.log
+  fi
+done
diff --git a/files/usr/local/bin/rssi_monitor b/files/usr/local/bin/rssi_monitor
index 2e21a166..c790c673 100755
--- a/files/usr/local/bin/rssi_monitor
+++ b/files/usr/local/bin/rssi_monitor
@@ -57,34 +57,39 @@ sub getRSSI
     delete $rssi{$_};
   }
 
-  open(FILE, "/usr/sbin/iw $iface station dump 2>&1 |") or die "/usr/sbin/iw failed $!";
+  chomp ($stationCount = `ls -1 /sys/kernel/debug/ieee80211/phy0/netdev:${iface}/stations | wc -l`); 
 
-  $neighborCount = 0;
-  while($line = <FILE>)
+  if ($stationCount >= 1) 
   {
-    if($line =~ /Station (\S+) \(on $iface\)/) { $mac = $1;}
-    if($antnum and $line =~ /signal:[ \t]+[-\d]+[ \t]*\[([-\d]+),[ \t]*([-\d]+)/)
-    {
-      $H = $1;
-      $V = $2;
-    }
+    open(FILE, "/usr/sbin/iw $iface station dump 2>&1 |") or die "/usr/sbin/iw failed $!";
 
-    if ((not $antnum) and $line =~ /signal:[ \t]+[-\d]+[ \t]*\[([-\d]+)\]/)
+    $neighborCount = 0;
+    while($line = <FILE>)
     {
-      $H = $1;
-    }
-    if ($H)
-    {
-      if ($H < -95) { $rssi{$mac}{"Hrssi"}=-96 ; }
-      else { $rssi{$mac}{"Hrssi"}=$H ; }
-      undef $H;
-      $neighborCount += 1;
-    }
-    if ($V)
-    {
-      if ($V < -95) { $rssi{$mac}{"Vrssi"}=-96 ; }
-      else { $rssi{$mac}{"Vrssi"}=$V ; }
-      undef $V;
+      if($line =~ /Station (\S+) \(on $iface\)/) { $mac = $1;}
+      if($antnum and $line =~ /signal:[ \t]+[-\d]+[ \t]*\[([-\d]+),[ \t]*([-\d]+)/)
+      {
+        $H = $1;
+        $V = $2;
+      }
+
+      if ((not $antnum) and $line =~ /signal:[ \t]+[-\d]+[ \t]*\[([-\d]+)\]/)
+      {
+        $H = $1;
+      }
+      if ($H)
+      {
+        if ($H < -95) { $rssi{$mac}{"Hrssi"}=-96 ; }
+        else { $rssi{$mac}{"Hrssi"}=$H ; }
+        undef $H;
+        $neighborCount += 1;
+      }
+      if ($V)
+      {
+        if ($V < -95) { $rssi{$mac}{"Vrssi"}=-96 ; }
+        else { $rssi{$mac}{"Vrssi"}=$V ; }
+        undef $V;
+      }
     }
   }
 }
@@ -95,14 +100,13 @@ sub getChannelScan
   $chnum += 1;
   if ($chnum == 8 or $chnum == 12 or $chnum == 100 or $chnum == 185) { $chnum -= 2; }
   if ($chnum == 0) { $chnum = 1; }
-  $freq = `iw list | grep "\\\[$chnum\\\]" | head -1`;
-  $freq =~ /([\d]+)[ \t]+MHz[ \t]+/;
+  $freq = `iwinfo $iface freqlist | grep "Channel $chnum" | head -1 | sed -e "s/\\.//"`;
+  $freq =~ /([\d]+)[ \t]+GHz/; 
   $freq = $1;
 }
 
-$antnum=`iw list | grep "Configured Antennas: TX" | cut -f6 -d" "`;
-chomp $antnum;
-if ($antnum eq "0x1")
+$antnum=`cat /sys/kernel/debug/ieee80211/phy0/ath9k/tx_chainmask`;
+if ($antnum == "1")
 {
   $antnum=0;
 }
@@ -241,75 +245,69 @@ for (keys %rssi)
   }
 }
 
-if ($amac or not $neighborCount)
+if ($amac)
 {
   getChannelScan();
 
-  if ($amac)
-  {
-    $datestring = localtime();
-    if ($antnum) {print $lfh "$datestring: before $amac [ $rssi{$amac}{'Hrssi'}, $rssi{$amac}{'Vrssi'} ]\n";}
-    else         {print $lfh "$datestring: before $amac [ $rssi{$amac}{'Hrssi'}]\n";}
-  }
+  $datestring = localtime();
+  if ($antnum) {print $lfh "$datestring: before $amac [ $rssi{$amac}{'Hrssi'}, $rssi{$amac}{'Vrssi'} ]\n";}
+  else         {print $lfh "$datestring: before $amac [ $rssi{$amac}{'Hrssi'}]\n";}
 
   system("/usr/sbin/iw $iface scan freq $freq passive > /dev/null");
 
-  if ($amac)
+  sleep 5;
+
+  $beforeH = $rssi{$amac}{"Hrssi"};
+  if ($antnum) { $beforeV = $rssi{$amac}{"Vrssi"}; }
+
+  getRSSI() ;
+  $datestring = localtime();
+  if ($antnum) {print $lfh "$datestring: after  $amac [ $rssi{$amac}{'Hrssi'}, $rssi{$amac}{'Vrssi'} ]\n";}
+  else         {print $lfh "$datestring: after  $amac [ $rssi{$amac}{'Hrssi'}]\n";}
+
+  $falpos = 0;
+  if ($antnum)
   {
-    sleep 5;
+    if  (abs ( $beforeH - $rssi{$amac}{"Hrssi"} ) <= 2 and
+         abs ( $beforeV - $rssi{$amac}{"Vrssi"} ) <= 2 ) { $falpos = 1; }
+  }
+  elsif (abs ( $beforeH - $rssi{$amac}{"Hrssi"} ) <= 2 ) { $falpos = 1; }
 
-    $beforeH = $rssi{$amac}{"Hrssi"};
-    if ($antnum) { $beforeV = $rssi{$amac}{"Vrssi"}; }
+  if ( $falpos )
+  {
+    # if a false-positive (within 2dB change after a reset), then add data point to statistics
+    $aveH = (($rssiHist{$amac}{"aveH"}*$rssiHist{$amac}{"num"})+ $beforeH )
+            / ($rssiHist{$amac}{"num"} + 1 );
+    $sdH = sqrt((($rssiHist{$amac}{"num"}-1)*($rssiHist{$amac}{"sdH"}**2) +
+            (($beforeH-$aveH)*($beforeH-$rssiHist{$amac}{"aveH"})))
+            /$rssiHist{$amac}{"num"});
+    chomp $aveH;
+    chomp $sdH;
+    $rssiHist{$amac}{"aveH"} = $aveH;
+    $rssiHist{$amac}{"sdH"} =  $sdH;
 
-    getRSSI() ;
-    $datestring = localtime();
-    if ($antnum) {print $lfh "$datestring: after  $amac [ $rssi{$amac}{'Hrssi'}, $rssi{$amac}{'Vrssi'} ]\n";}
-    else         {print $lfh "$datestring: after  $amac [ $rssi{$amac}{'Hrssi'}]\n";}
-
-    $falpos = 0;
     if ($antnum)
     {
-      if  (abs ( $beforeH - $rssi{$amac}{"Hrssi"} ) <= 2 and
-           abs ( $beforeV - $rssi{$amac}{"Vrssi"} ) <= 2 ) { $falpos = 1; }
+      $aveV = (($rssiHist{$amac}{"aveV"}*$rssiHist{$amac}{"num"})+ $beforeV ) /
+               ($rssiHist{$amac}{"num"} + 1 );
+      $sdV = sqrt((($rssiHist{$amac}{"num"}-1)*($rssiHist{$amac}{"sdV"}**2) +
+              (($beforeV-$aveV)*($beforeV-$rssiHist{$amac}{"aveV"}))) /
+              $rssiHist{$amac}{"num"});
+      chomp $aveV;
+      chomp $sdV;
+      $rssiHist{$amac}{"aveV"} = $aveV;
+      $rssiHist{$amac}{"sdV"} =  $sdV;
     }
-    elsif (abs ( $beforeH - $rssi{$amac}{"Hrssi"} ) <= 2 ) { $falpos = 1; }
 
-    if ( $falpos )
+    if ($rssiHist{$amac}{"num"} < 60 )
     {
-      # if a false-positive (within 2dB change after a reset), then add data point to statistics
-      $aveH = (($rssiHist{$amac}{"aveH"}*$rssiHist{$amac}{"num"})+ $beforeH )
-              / ($rssiHist{$amac}{"num"} + 1 );
-      $sdH = sqrt((($rssiHist{$amac}{"num"}-1)*($rssiHist{$amac}{"sdH"}**2) +
-              (($beforeH-$aveH)*($beforeH-$rssiHist{$amac}{"aveH"})))
-              /$rssiHist{$amac}{"num"});
-      chomp $aveH;
-      chomp $sdH;
-      $rssiHist{$amac}{"aveH"} = $aveH;
-      $rssiHist{$amac}{"sdH"} =  $sdH;
-
-      if ($antnum)
-      {
-        $aveV = (($rssiHist{$amac}{"aveV"}*$rssiHist{$amac}{"num"})+ $beforeV ) /
-                 ($rssiHist{$amac}{"num"} + 1 );
-        $sdV = sqrt((($rssiHist{$amac}{"num"}-1)*($rssiHist{$amac}{"sdV"}**2) +
-                (($beforeV-$aveV)*($beforeV-$rssiHist{$amac}{"aveV"}))) /
-                $rssiHist{$amac}{"num"});
-        chomp $aveV;
-        chomp $sdV;
-        $rssiHist{$amac}{"aveV"} = $aveV;
-        $rssiHist{$amac}{"sdV"} =  $sdV;
-      }
-
-      if ($rssiHist{$amac}{"num"} < 60 )
-      {
-        # keep statistics to 60 sample (minute) moving window
-        $rssiHist{$amac}{"num"} += 1;
-      }
-      $rssiHist{$amac}{"last"} = $now + 5 ;
-
-      $datestring = localtime();
-      print $lfh "$datestring: $amac Possible valid data point, adding to statistics.\n";
+      # keep statistics to 60 sample (minute) moving window
+      $rssiHist{$amac}{"num"} += 1;
     }
+    $rssiHist{$amac}{"last"} = $now + 5 ;
+
+    $datestring = localtime();
+    print $lfh "$datestring: $amac Possible valid data point, adding to statistics.\n";
   }
 }
 
diff --git a/files/www/cgi-bin/perlfunc.pm b/files/www/cgi-bin/perlfunc.pm
index b4cd836b..658f7170 100644
--- a/files/www/cgi-bin/perlfunc.pm
+++ b/files/www/cgi-bin/perlfunc.pm
@@ -607,29 +607,29 @@ sub get_wifi_signal
   chomp $wifiintf;
   my ($SignalLevel) = "N/A";
   my ($NoiseFloor) = "N/A";
-  foreach(`iw dev $wifiintf station dump`)
+  foreach(`iwinfo $wifiintf assoclient`)
   {
-    next unless /.+signal:\s+([-]?[\d]+)/;
+    next unless /.+[A-F0-9]{2}:[A-F0-9]{2}:[A-F0-9]{2}\s+([-]?[\d]+)/;
     if ( $SignalLevel <= "$1" || $SignalLevel == "N/A" )
     {
       $SignalLevel=$1;
     }
   }
 
-  foreach(`iw dev $wifiintf survey dump|grep -A 1 \"\\[in use\\]\"`)
-  {
-    next unless /([\d\-]+) dBm/;
+  open( my $NoiseFH , "<" , "/sys/kernel/debug/ieee80211/phy0/ath9k/dump_nfcal") or return ("N/A","N/A");
+  while (<$NoiseFH>) {
+    next unless /Channel Noise Floor : ([-]?[0-9]+)/;
     $NoiseFloor=$1;
   }
+  close($NoiseFH);
 
   if ( $NoiseFloor == "N/A" )
   {
-    open( my $NoiseFH , "<" , "/sys/kernel/debug/ieee80211/phy0/ath9k/dump_nfcal") or return ("N/A","N/A");
-    while (<$NoiseFH>) {
-      next unless /Channel Noise Floor : ([-]?[0-9]+)/;
+    foreach(`iwinfo $wifiintf info | grep Signal`)
+    {
+      next unless /([\d\-]+) dBm/;
       $NoiseFloor=$1;
     }
-    close($NoiseFH);
   }
 
   if ( $SignalLevel == "N/A" || $NoiseFloor == "N/A" )