diff --git a/src/frame.ts b/src/frame.ts
index 0e81a34..792eb68 100644
--- a/src/frame.ts
+++ b/src/frame.ts
@@ -19,6 +19,8 @@ import type {
   TelemetryUnitPayload,
   WeatherPayload,
   RawGPSPayload,
+  StationCapabilitiesPayload,
+  ThirdPartyPayload,
 } from "./frame.types";
 import { Position } from "./position";
 import { base91ToNumber } from "./parser";
@@ -2037,24 +2039,194 @@ export class Frame implements IFrame {
     payload: Payload | null;
     segment?: Segment[];
   } {
-    // TODO: Implement capabilities decoding with section emission
-    return { payload: withStructure ? null : null };
+    try {
+      if (this.payload.length < 2) return { payload: null };
+
+      // Extract the text after the '<' identifier
+      let rest = this.payload.substring(1).trim();
+
+      // Some implementations include a closing '>' or other trailing chars; strip common wrappers
+      if (rest.endsWith(">")) rest = rest.slice(0, -1).trim();
+
+      // Split capabilities by commas, semicolons or whitespace
+      const tokens = rest
+        .split(/[,;\s]+/)
+        .map((t) => t.trim())
+        .filter(Boolean);
+
+      const payload: StationCapabilitiesPayload = {
+        type: "capabilities",
+        capabilities: tokens,
+      } as const;
+
+      if (withStructure) {
+        const segments: Segment[] = [];
+        segments.push({
+          name: "capabilities",
+          data: new TextEncoder().encode(rest).buffer,
+          isString: true,
+          fields: [
+            {
+              type: FieldType.STRING,
+              name: "capabilities",
+              length: rest.length,
+            },
+          ],
+        });
+
+        for (const cap of tokens) {
+          segments.push({
+            name: "capability",
+            data: new TextEncoder().encode(cap).buffer,
+            isString: true,
+            fields: [
+              {
+                type: FieldType.STRING,
+                name: "capability",
+                length: cap.length,
+              },
+            ],
+          });
+        }
+
+        return { payload, segment: segments };
+      }
+
+      return { payload };
+    } catch {
+      return { payload: null };
+    }
   }
 
   private decodeUserDefined(withStructure: boolean = false): {
     payload: Payload | null;
     segment?: Segment[];
   } {
-    // TODO: Implement user-defined decoding with section emission
-    return { payload: withStructure ? null : null };
+    try {
+      if (this.payload.length < 2) return { payload: null };
+
+      // content after '{'
+      const rest = this.payload.substring(1);
+
+      // user packet type is first token (up to first space) often like '01' or 'TYP'
+      const match = rest.match(/^([^\s]+)\s*(.*)$/s);
+      let userPacketType = "";
+      let data = "";
+      if (match) {
+        userPacketType = match[1] || "";
+        data = (match[2] || "").trim();
+      }
+
+      const payloadObj = {
+        type: "user-defined",
+        userPacketType,
+        data,
+      } as const;
+
+      if (withStructure) {
+        const segments: Segment[] = [];
+        segments.push({
+          name: "user-defined",
+          data: new TextEncoder().encode(rest).buffer,
+          isString: true,
+          fields: [
+            { type: FieldType.STRING, name: "raw", length: rest.length },
+          ],
+        });
+
+        segments.push({
+          name: "user-packet-type",
+          data: new TextEncoder().encode(userPacketType).buffer,
+          isString: true,
+          fields: [
+            {
+              type: FieldType.STRING,
+              name: "type",
+              length: userPacketType.length,
+            },
+          ],
+        });
+
+        segments.push({
+          name: "user-data",
+          data: new TextEncoder().encode(data).buffer,
+          isString: true,
+          fields: [
+            { type: FieldType.STRING, name: "data", length: data.length },
+          ],
+        });
+
+        return { payload: payloadObj as unknown as Payload, segment: segments };
+      }
+
+      return { payload: payloadObj as unknown as Payload };
+    } catch {
+      return { payload: null };
+    }
   }
 
   private decodeThirdParty(withStructure: boolean = false): {
     payload: Payload | null;
     segment?: Segment[];
   } {
-    // TODO: Implement third-party decoding with section emission
-    return { payload: withStructure ? null : null };
+    try {
+      if (this.payload.length < 2) return { payload: null };
+
+      // Content after '}' is the encapsulated third-party frame or raw data
+      const rest = this.payload.substring(1);
+
+      // Attempt to parse the embedded text as a full APRS frame (route:payload)
+      let nestedFrame: Frame | undefined;
+      try {
+        // parseFrame is defined in this module; use Frame.parse to attempt parse
+        nestedFrame = Frame.parse(rest);
+      } catch {
+        nestedFrame = undefined;
+      }
+
+      const payloadObj: ThirdPartyPayload = {
+        type: "third-party",
+        comment: rest,
+        ...(nestedFrame ? { frame: nestedFrame } : {}),
+      } as const;
+
+      if (withStructure) {
+        const segments: Segment[] = [];
+
+        segments.push({
+          name: "third-party",
+          data: new TextEncoder().encode(rest).buffer,
+          isString: true,
+          fields: [
+            { type: FieldType.STRING, name: "raw", length: rest.length },
+          ],
+        });
+
+        if (nestedFrame) {
+          // Include a short section pointing to the nested frame's data (stringified)
+          const nf = nestedFrame;
+          const nfStr = `${nf.source.toString()}>${nf.destination.toString()}:${nf.payload}`;
+          segments.push({
+            name: "third-party-nested-frame",
+            data: new TextEncoder().encode(nfStr).buffer,
+            isString: true,
+            fields: [
+              {
+                type: FieldType.STRING,
+                name: "nested",
+                length: nfStr.length,
+              },
+            ],
+          });
+        }
+
+        return { payload: payloadObj as unknown as Payload, segment: segments };
+      }
+
+      return { payload: payloadObj as unknown as Payload };
+    } catch {
+      return { payload: null };
+    }
   }
 
   public static fromString(data: string): Frame {
diff --git a/src/frame.types.ts b/src/frame.types.ts
index c3a8eb7..3a1387e 100644
--- a/src/frame.types.ts
+++ b/src/frame.types.ts
@@ -276,8 +276,8 @@ export interface UserDefinedPayload {
 // Third-Party Traffic Payload
 export interface ThirdPartyPayload {
   type: "third-party";
-  header: string; // Source path of third-party packet
-  payload: string; // Nested APRS packet
+  frame?: IFrame; // Optional nested frame if payload contains another APRS frame
+  comment?: string; // Optional comment
 }
 
 // DF Report Payload
diff --git a/test/frame.capabilities.test.ts b/test/frame.capabilities.test.ts
new file mode 100644
index 0000000..e16ff8f
--- /dev/null
+++ b/test/frame.capabilities.test.ts
@@ -0,0 +1,34 @@
+import { describe, it, expect } from "vitest";
+import { Frame } from "../src/frame";
+import type { Payload, StationCapabilitiesPayload } from "../src/frame.types";
+import { Dissected } from "@hamradio/packet";
+
+describe("Frame.decodeCapabilities", () => {
+  it("parses comma separated capabilities", () => {
+    const data = "CALL>APRS:<IGATE,MSG_CNT";
+    const frame = Frame.fromString(data);
+    const decoded = frame.decode() as StationCapabilitiesPayload;
+    expect(decoded).not.toBeNull();
+    expect(decoded.type).toBe("capabilities");
+    expect(Array.isArray(decoded.capabilities)).toBeTruthy();
+    expect(decoded.capabilities).toContain("IGATE");
+    expect(decoded.capabilities).toContain("MSG_CNT");
+  });
+
+  it("emits structure sections when requested", () => {
+    const data = "CALL>APRS:<IGATE MSG_CNT>";
+    const frame = Frame.fromString(data);
+    const res = frame.decode(true) as {
+      payload: Payload | null;
+      structure: Dissected;
+    };
+    expect(res.payload).not.toBeNull();
+    if (res.payload && res.payload.type !== "capabilities")
+      throw new Error("expected capabilities payload");
+    expect(res.structure).toBeDefined();
+    const caps = res.structure.find((s) => s.name === "capabilities");
+    expect(caps).toBeDefined();
+    const capEntry = res.structure.find((s) => s.name === "capability");
+    expect(capEntry).toBeDefined();
+  });
+});
diff --git a/test/frame.userdefined.test.ts b/test/frame.userdefined.test.ts
new file mode 100644
index 0000000..195e2ad
--- /dev/null
+++ b/test/frame.userdefined.test.ts
@@ -0,0 +1,38 @@
+import { describe, it, expect } from "vitest";
+import { Dissected } from "@hamradio/packet";
+import { Frame } from "../src/frame";
+import type { UserDefinedPayload } from "../src/frame.types";
+
+describe("Frame.decodeUserDefined", () => {
+  it("parses packet type only", () => {
+    const data = "CALL>APRS:{01";
+    const frame = Frame.fromString(data);
+    const decoded = frame.decode() as UserDefinedPayload;
+    expect(decoded).not.toBeNull();
+    expect(decoded.type).toBe("user-defined");
+    expect(decoded.userPacketType).toBe("01");
+    expect(decoded.data).toBe("");
+  });
+
+  it("parses packet type and data and emits sections", () => {
+    const data = "CALL>APRS:{TEX Hello world";
+    const frame = Frame.fromString(data);
+    const res = frame.decode(true) as {
+      payload: UserDefinedPayload;
+      structure: Dissected;
+    };
+    expect(res.payload).not.toBeNull();
+    expect(res.payload.type).toBe("user-defined");
+    expect(res.payload.userPacketType).toBe("TEX");
+    expect(res.payload.data).toBe("Hello world");
+
+    const raw = res.structure.find((s) => s.name === "user-defined");
+    const typeSection = res.structure.find(
+      (s) => s.name === "user-packet-type",
+    );
+    const dataSection = res.structure.find((s) => s.name === "user-data");
+    expect(raw).toBeDefined();
+    expect(typeSection).toBeDefined();
+    expect(dataSection).toBeDefined();
+  });
+});