diff --git a/mainwindow.cpp b/mainwindow.cpp
index a75966b..21bbd7b 100644
--- a/mainwindow.cpp
+++ b/mainwindow.cpp
@@ -10289,6 +10289,14 @@ void MainWindow::processCommandActivity() {
             continue;
         }
 
+        // PROCESS NACKS
+        else if (d.cmd == " NACK" && !isAllCall){
+            qDebug() << "skipping incoming nack" << d.text;
+
+            // make sure this is explicit
+            continue;
+        }
+
         // PROCESS BUFFERED CMD
         else if (d.cmd == " CMD" && !isAllCall){
             qDebug() << "skipping incoming command" << d.text;
diff --git a/varicode.cpp b/varicode.cpp
index cb771a2..b5cbb71 100644
--- a/varicode.cpp
+++ b/varicode.cpp
@@ -51,7 +51,8 @@ QMap<QString, int> directed_cmds = {
     {"?",              0  }, // compat
 
     //{" ",            1  }, // unused
-    //{" ",            2  }, // unused
+
+    {" NACK",          2  }, // negative acknowledge
 
     {" HEARING?",      3  }, // query station calls heard
 
@@ -104,7 +105,7 @@ QMap<QString, int> directed_cmds = {
 };
 
 // commands allowed to be processed
-QSet<int> allowed_cmds = {-1, 0, /*1,*/ /*2,*/ 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15, 16, 17, 18, 19, 20, 21, 22, 23, 24, 25, 26, 27, 28, 29, 30, 31};
+QSet<int> allowed_cmds = {-1, 0, /*1,*/ 2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15, 16, 17, 18, 19, 20, 21, 22, 23, 24, 25, 26, 27, 28, 29, 30, 31};
 
 // commands that result in an autoreply (which can be relayed)
 QSet<int> autoreply_cmds = {0, 3, 4, 6, 9, 10, 11, 12, 13, 16, 30};
@@ -129,10 +130,10 @@ QMap<int, int> checksum_cmds = {
 };
 
 QString callsign_pattern = QString("(?<callsign>[@]?[A-Z0-9/]+)");
-QString optional_cmd_pattern = QString("(?<cmd>\\s?(?:AGN[?]|QSL[?]|HW CPY[?]|APRS[:]|MSG TO[:]|SNR[?]|INFO[?]|GRID[?]|STATUS[?]|QUERY MSGS[?]|HEARING[?]|(?:(?:STATUS|HEARING|QUERY CALL|QUERY MSGS|QUERY|CMD|MSG|ACK|73|YES|NO|SNR|QSL|RR|SK|FB|INFO|GRID)(?=[ ]|$))|[?> ]))?");
+QString optional_cmd_pattern = QString("(?<cmd>\\s?(?:AGN[?]|QSL[?]|HW CPY[?]|APRS[:]|MSG TO[:]|SNR[?]|INFO[?]|GRID[?]|STATUS[?]|QUERY MSGS[?]|HEARING[?]|(?:(?:STATUS|HEARING|QUERY CALL|QUERY MSGS|QUERY|CMD|MSG|NACK|ACK|73|YES|NO|SNR|QSL|RR|SK|FB|INFO|GRID)(?=[ ]|$))|[?> ]))?");
 QString optional_grid_pattern = QString("(?<grid>\\s?[A-R]{2}[0-9]{2})?");
 QString optional_extended_grid_pattern = QString("^(?<grid>\\s?(?:[A-R]{2}[0-9]{2}(?:[A-X]{2}(?:[0-9]{2})?)*))?");
-QString optional_num_pattern = QString("(?<num>(?<=SNR|ACK)\\s?[-+]?(?:3[01]|[0-2]?[0-9]))?");
+QString optional_num_pattern = QString("(?<num>(?<=SNR|\\bACK)\\s?[-+]?(?:3[01]|[0-2]?[0-9]))?");
 
 QRegularExpression directed_re("^"                    +
                                callsign_pattern       +
@@ -1545,8 +1546,8 @@ QStringList Varicode::unpackDirectedMessage(const QString &text, quint8 *pType){
     quint32 packed_to = Varicode::bitsToInt(bits.mid(31, 28));
     quint8 packed_cmd = Varicode::bitsToInt(bits.mid(59, 5));
 
-    bool portable_from = (extra >> 7) & 1 == 1;
-    bool portable_to = (extra >> 6) & 1 == 1;
+    bool portable_from = ((extra >> 7) & 1) == 1;
+    bool portable_to = ((extra >> 6) & 1) == 1;
     extra = extra % 64;
 
     QString from = Varicode::unpackCallsign(packed_from, portable_from);