Bugfixes:

 - mDNS client now picks a NIC with a gateway, fixes #4
 - mDNS network adaptor can now be specified via command line args
 - Sennheiser frequency scan now resets the frequency of the receiver after the scan, fixes #6
 - Improvements to the robustness of Shure frequency scans, fixes #5

WirelessMicSuiteServer/IWirelessMicReceiver.cs

@@ -359,6 +359,10 @@ public struct RFScanData
     /// The current state of the RF scan operation.
     /// </summary>
     public Status State { get; internal set; }
+    /// <summary>
+    /// The error message related to the state of the RF scan operation.
+    /// </summary>
+    public string? StatusMessage { get; internal set; }
 
     /// <summary>
     /// An RF spectrum sample.

WirelessMicSuiteServer/Program.cs

@@ -32,7 +32,7 @@ public static void Main(string[] args)
 
         WirelessMicManager micManager = new([
             new ShureUHFRManager() { PollingPeriodMS = meterInterval },
-            new SennheiserSSCManager() { PollingPeriodMS = meterInterval }
+            new SennheiserSSCManager((string?)cli.ParsedArgs.GetValueOrDefault("--nic-address")) { PollingPeriodMS = meterInterval }
         ]);
         WebSocketAPIManager wsAPIManager = new(micManager, meterInterval);
         if (cli.ParsedArgs.ContainsKey("--meters"))
@@ -45,7 +45,8 @@ private static CommandLineOptions CreateCommandLineArgs(string[] args)
         return new CommandLineOptions([
             new("--meters", "-m", help: "Displays ASCII-art meters in the terminal for the connected wireless mics. Don't use this in production."),
             new("--meter-interval", "-i", argType: CommandLineArgType.Uint, defaultValue: 50u, help:"Sets the interval at which metering information should be polled from the wireless receivers. This is specified in milli-seconds."),
-            new("--save-dir", "-s", argType: CommandLineArgType.String, defaultValue: "save", help:"Specifies a directory to save.")
+            new("--save-dir", "-s", argType: CommandLineArgType.String, defaultValue: "save", help:"Specifies a directory to save."),
+            new("--nic-address", "-a", argType: CommandLineArgType.String, defaultValue: null, help:"Specifies the IP address of the network adapter to use.")
         ], args);
     }
 

WirelessMicSuiteServer/SennheiserSSC/MDNSClient.cs

@@ -30,7 +30,7 @@ public class MDNSClient : IDisposable
 
     public event Action<MDNSMessage>? OnMDNSMessage;
 
-    public MDNSClient()
+    public MDNSClient(string? preferredIp)
     {
         cancellationTokenSource = new();
         cancellationToken = cancellationTokenSource.Token;
@@ -50,11 +50,22 @@ public MDNSClient()
         Log("List network interfaces: ");
         List<IPAddress> addresses = [];
         IPAddress? addr = null;
+        IPAddress? prefferedIpAddr = null;
+        if (!string.IsNullOrEmpty(preferredIp))
+            if (!IPAddress.TryParse(preferredIp, out prefferedIpAddr))
+                Log($"Couldn't parse '{preferredIp}' as an IP address!", LogSeverity.Warning);
         foreach (var nic in NetworkInterface.GetAllNetworkInterfaces())
         {
-            var nicAddr = nic.GetIPProperties().UnicastAddresses.Select(x => x.Address);
+            var ipProps = nic.GetIPProperties();
+            var nicAddr = ipProps.UnicastAddresses.Select(x => x.Address);
             addresses.AddRange(nicAddr);
-            if (nicAddr.FirstOrDefault(x => x.AddressFamily == AddressFamily.InterNetwork) is IPAddress naddr)
+            if (prefferedIpAddr != null && nicAddr.Contains(prefferedIpAddr))
+            {
+                addr = prefferedIpAddr;
+                break;
+            }
+            if (nicAddr.FirstOrDefault(x => x.AddressFamily == AddressFamily.InterNetwork) is IPAddress naddr
+                && ipProps.GatewayAddresses.Count > 0)
                 addr ??= naddr;
             Log($"\t{nic.Name}: {string.Join(", ", nicAddr)}");
         }

WirelessMicSuiteServer/SennheiserSSC/SennheiserSSCManager.cs

@@ -35,7 +35,7 @@ public class SennheiserSSCManager : IWirelessMicReceiverManager
     public int PollingPeriodMS { get; set; } = 100;
     public ObservableCollection<IWirelessMicReceiver> Receivers { get; init; }
 
-    public SennheiserSSCManager()
+    public SennheiserSSCManager(string? preferredNicAddress)
     {
         Receivers = [];
         receiversDict = [];
@@ -61,7 +61,7 @@ public SennheiserSSCManager()
         socket.Bind(new IPEndPoint(IPAddress.Any, 0));
         rxTask = Task.Run(RXTask);
         txTask = Task.Run(TXTask);
-        mDNSClient = new MDNSClient();
+        mDNSClient = new MDNSClient(preferredNicAddress);
         mDNSClient.OnMDNSMessage += OnMDNSMessage;
         discoveryTask = new Timer(_ =>
         {

WirelessMicSuiteServer/SennheiserSSC/SennheiserSSCWirelessMic.cs

@@ -28,6 +28,7 @@ public class SennheiserSSCWirelessMic : IWirelessMic
     private float? batteryLevel;
 
     private bool isTXConnected = false;
+    private ulong? lastFrequency;
     private bool isCollectingRFSamples;
     private Task<RFScanData>? rfScanInProgress;
     private MeteringData? lastMeterData;
@@ -184,6 +185,7 @@ public Task<RFScanData> StartRFScan(FrequencyRange range, ulong stepSize)
             rfScanData.StepSize = stepSize;
             rfScanData.Samples = [];
             rfSamples.Clear();
+            lastFrequency = frequency;
 
             isCollectingRFSamples = true;
             stepSize = Math.Min((stepSize / 25000) * 25000, stepSize);
@@ -194,7 +196,7 @@ public Task<RFScanData> StartRFScan(FrequencyRange range, ulong stepSize)
                 for (ulong freq = range.StartFrequency; freq < range.EndFrequency + 1; freq += stepSize)
                 {
                     Frequency = freq;
-                    Thread.Sleep(100);
+                    Thread.Sleep(120);
                     rfScanData.Progress = ++i/(float)nsteps;
                 }
             }
@@ -206,6 +208,7 @@ public Task<RFScanData> StartRFScan(FrequencyRange range, ulong stepSize)
                 rfScanData.Samples.Add(new(sample.Key, sample.Value.sample / sample.Value.n));
             }
 
+            Frequency = lastFrequency;
             rfScanData.State = RFScanData.Status.Completed;
 
             return rfScanData;