diff --git a/lib/aprsme/callsign.ex b/lib/aprsme/callsign.ex
index e49cc27..cb5b2a3 100644
--- a/lib/aprsme/callsign.ex
+++ b/lib/aprsme/callsign.ex
@@ -40,12 +40,8 @@ defmodule Aprsme.Callsign do
   def valid?(callsign) when is_binary(callsign) do
     trimmed = String.trim(callsign)
 
-    cond do
-      trimmed == "" -> false
-      byte_size(trimmed) < 3 -> false
-      byte_size(trimmed) > 15 -> false
-      true -> Regex.match?(~r/^[A-Z0-9]+(-[A-Z0-9]{1,2})?$/i, trimmed)
-    end
+    # Accept any non-empty callsign
+    trimmed != ""
   end
 
   def valid?(_), do: false
@@ -74,10 +70,13 @@ defmodule Aprsme.Callsign do
   def extract_base(nil), do: ""
 
   def extract_base(callsign) when is_binary(callsign) do
+    # Split on last hyphen to get base callsign
     case String.split(callsign, "-") do
-      [base, _ssid] -> base
-      [base] -> base
-      _ -> ""
+      parts when length(parts) > 1 ->
+        parts |> Enum.drop(-1) |> Enum.join("-")
+
+      _ ->
+        callsign
     end
   end
 
@@ -98,9 +97,9 @@ defmodule Aprsme.Callsign do
   def extract_ssid(nil), do: "0"
 
   def extract_ssid(callsign) when is_binary(callsign) do
+    # Extract whatever comes after the last hyphen as SSID
     case String.split(callsign, "-") do
-      [_base, ssid] -> ssid
-      [_base] -> "0"
+      parts when length(parts) > 1 -> List.last(parts)
       _ -> "0"
     end
   end
@@ -122,10 +121,15 @@ defmodule Aprsme.Callsign do
   def extract_parts(nil), do: {"", "0"}
 
   def extract_parts(callsign) when is_binary(callsign) do
+    # Split on last hyphen to separate base and SSID
     case String.split(callsign, "-") do
-      [base, ssid] -> {base, ssid}
-      [base] -> {base, "0"}
-      _ -> {"", "0"}
+      parts when length(parts) > 1 ->
+        ssid = List.last(parts)
+        base = parts |> Enum.drop(-1) |> Enum.join("-")
+        {base, ssid}
+
+      _ ->
+        {callsign, "0"}
     end
   end
 
diff --git a/test/aprsme/callsign_test.exs b/test/aprsme/callsign_test.exs
new file mode 100644
index 0000000..98fc377
--- /dev/null
+++ b/test/aprsme/callsign_test.exs
@@ -0,0 +1,58 @@
+defmodule Aprsme.CallsignTest do
+  use ExUnit.Case, async: true
+
+  alias Aprsme.Callsign
+
+  describe "valid?/1" do
+    test "validates standard callsigns" do
+      assert Callsign.valid?("K5ABC")
+      assert Callsign.valid?("W1XYZ")
+      assert Callsign.valid?("N0CALL")
+    end
+
+    test "validates callsigns with SSID" do
+      assert Callsign.valid?("K5ABC-1")
+      assert Callsign.valid?("W1XYZ-15")
+      assert Callsign.valid?("N0CALL-9")
+    end
+
+    test "validates callsigns with hyphens in base callsign like VE-KTKI" do
+      assert Callsign.valid?("VE-KTKI")
+      assert Callsign.valid?("VE-KTKI-1")
+      assert Callsign.valid?("VE-TEST")
+    end
+
+    test "rejects only empty callsigns" do
+      refute Callsign.valid?("")
+      refute Callsign.valid?(" ")
+
+      # Now accepts any non-empty string
+      assert Callsign.valid?("123")
+      assert Callsign.valid?("-ABC")
+      assert Callsign.valid?("ABC-")
+      assert Callsign.valid?("ABC-123")
+      assert Callsign.valid?("ABC--1")
+    end
+
+    test "handles nil input" do
+      refute Callsign.valid?(nil)
+    end
+  end
+
+  describe "normalize/1" do
+    test "converts to uppercase and trims whitespace" do
+      assert Callsign.normalize("k5abc") == "K5ABC"
+      assert Callsign.normalize(" W1XYZ ") == "W1XYZ"
+      assert Callsign.normalize("  n0call-9  ") == "N0CALL-9"
+    end
+
+    test "normalizes callsigns with hyphens in base" do
+      assert Callsign.normalize("ve-ktki") == "VE-KTKI"
+      assert Callsign.normalize(" VE-KTKI-1 ") == "VE-KTKI-1"
+    end
+
+    test "handles nil input" do
+      assert Callsign.normalize(nil) == ""
+    end
+  end
+end