move netId and sysId 0 check;

src/p25/Control.cpp

@@ -1135,6 +1135,15 @@ void Control::processNetwork()
 
     uint8_t frameType = p25::P25_FT_DATA_UNIT;
 
+    // if the netId or sysId is missing; default to our netId and sysId
+    if (netId == 0U) {
+        netId = lc::LC::getSiteData().netId();
+    }
+
+    if (sysId == 0U) {
+        sysId = lc::LC::getSiteData().sysId();
+    }
+
     if (m_debug) {
         LogDebug(LOG_NET, "P25, duid = $%02X, lco = $%02X, MFId = $%02X, srcId = %u, dstId = %u, len = %u", duid, lco, MFId, srcId, dstId, length);
     }

src/p25/packet/Voice.cpp

@@ -1430,14 +1430,6 @@ void Voice::writeNet_LDU1()
 
     // is the network peer a different WACN or system ID?
     if (m_p25->m_control && m_p25->m_allowExplicitSourceId) {
-        if (netId == 0U) {
-            netId = lc::LC::getSiteData().netId();
-        }
-
-        if (sysId == 0U) {
-            sysId = lc::LC::getSiteData().sysId();
-        }
-
         if (sysId != lc::LC::getSiteData().sysId()) {
             // per TIA-102.AABD-D transmit EXPLICIT_SOURCE_ID every other frame (e.g. every other LDU1)
             m_roamLDU1Count++;