diff --git a/drb-c2-core/app/routers/nodes.py b/drb-c2-core/app/routers/nodes.py
index cbacbe1..297b3e5 100644
--- a/drb-c2-core/app/routers/nodes.py
+++ b/drb-c2-core/app/routers/nodes.py
@@ -1,5 +1,5 @@
 import secrets
-from fastapi import APIRouter, HTTPException, Depends
+from fastapi import APIRouter, HTTPException, Depends, Query
 from app.models import CommandPayload
 from app.internal import firestore as fstore
 from app.internal.mqtt_handler import mqtt_handler
@@ -93,7 +93,12 @@ async def reissue_node_key(node_id: str, _: dict = Depends(require_admin_token))
 
 
 @router.post("/{node_id}/config/{system_id}")
-async def assign_system(node_id: str, system_id: str):
+async def assign_system(
+    node_id: str,
+    system_id: str,
+    hardware_preset: str = Query("rtl-sdr-v3"),
+    ppm_override: float = Query(None),
+):
     """
     Assign a system to a node. Fetches the system config from Firestore
     and pushes it to the node via MQTT, then marks the node as configured.
@@ -106,13 +111,22 @@ async def assign_system(node_id: str, system_id: str):
     if not system:
         raise HTTPException(404, f"System '{system_id}' not found.")
 
-    # Push config to the node via MQTT
-    mqtt_handler.push_config(node_id, system)
+    # Include hardware preset in the push so the edge node applies it when
+    # generating the OP25 config. Strip it from the system doc first so it
+    # doesn't collide with SystemConfig field validation on the node side.
+    push_payload = {**system, "hardware_preset": hardware_preset}
+    if ppm_override is not None:
+        push_payload["ppm_override"] = ppm_override
+    mqtt_handler.push_config(node_id, push_payload)
 
     # Update Firestore
-    await fstore.doc_update("nodes", node_id, {
+    node_updates = {
         "assigned_system_id": system_id,
         "configured": True,
-    })
+        "hardware_preset": hardware_preset,
+    }
+    if ppm_override is not None:
+        node_updates["ppm_override"] = ppm_override
+    await fstore.doc_update("nodes", node_id, node_updates)
 
     return {"ok": True}
diff --git a/drb-frontend/components/NodeConfigModal.tsx b/drb-frontend/components/NodeConfigModal.tsx
index f9c8340..7a5cba6 100644
--- a/drb-frontend/components/NodeConfigModal.tsx
+++ b/drb-frontend/components/NodeConfigModal.tsx
@@ -10,18 +10,29 @@ interface Props {
   onClose: () => void;
 }
 
+const PRESETS = [
+  { value: "rtl-sdr-v3",     label: "RTL-SDR v3",      hint: "TCXO — LNA:34, tracking off" },
+  { value: "nesdr-smart-v4", label: "NESDR Smart v4",   hint: "TCXO — LNA:32, tracking off" },
+  { value: "other",          label: "Other",             hint: "LNA:32, tracking on" },
+];
+
 export function NodeConfigModal({ node, systems, onClose }: Props) {
   const [systemId, setSystemId] = useState("");
+  const [preset, setPreset] = useState("rtl-sdr-v3");
+  const [ppm, setPpm] = useState("0");
   const [saving, setSaving] = useState(false);
   const [error, setError] = useState<string | null>(null);
 
+  const ppmVal = parseFloat(ppm);
+  const ppmOverride = !isNaN(ppmVal) && ppmVal !== 0 ? ppmVal : undefined;
+
   async function handleSubmit(e: React.FormEvent) {
     e.preventDefault();
     if (!systemId) return;
     setSaving(true);
     setError(null);
     try {
-      await c2api.assignSystem(node.node_id, systemId);
+      await c2api.assignSystem(node.node_id, systemId, preset, ppmOverride);
       onClose();
     } catch (err) {
       setError(err instanceof Error ? err.message : "Failed to assign system.");
@@ -30,6 +41,8 @@ export function NodeConfigModal({ node, systems, onClose }: Props) {
     }
   }
 
+  const selectedPreset = PRESETS.find((p) => p.value === preset);
+
   return (
     <div className="fixed inset-0 bg-black/70 flex items-center justify-center z-50">
       <div className="bg-gray-900 border border-gray-700 rounded-xl p-6 w-full max-w-md font-mono">
@@ -57,6 +70,36 @@ export function NodeConfigModal({ node, systems, onClose }: Props) {
             </select>
           </div>
 
+          <div>
+            <label className="block text-xs text-gray-400 mb-1">SDR Hardware</label>
+            <select
+              value={preset}
+              onChange={(e) => setPreset(e.target.value)}
+              className="w-full bg-gray-800 border border-gray-700 rounded-lg px-3 py-2 text-white text-sm focus:outline-none focus:border-indigo-500"
+            >
+              {PRESETS.map((p) => (
+                <option key={p.value} value={p.value}>{p.label}</option>
+              ))}
+            </select>
+            {selectedPreset && (
+              <p className="text-xs text-gray-600 mt-1">{selectedPreset.hint}</p>
+            )}
+          </div>
+
+          <div>
+            <label className="block text-xs text-gray-400 mb-1">
+              PPM offset <span className="text-gray-600">(0 = use preset default; calibrate via OP25 web UI)</span>
+            </label>
+            <input
+              type="number"
+              value={ppm}
+              onChange={(e) => setPpm(e.target.value)}
+              step="0.1"
+              className="w-full bg-gray-800 border border-gray-700 rounded-lg px-3 py-2 text-white text-sm font-mono focus:outline-none focus:border-indigo-500"
+              placeholder="0"
+            />
+          </div>
+
           {error && <p className="text-red-400 text-xs">{error}</p>}
 
           <div className="flex gap-3 pt-1">
diff --git a/drb-frontend/lib/c2api.ts b/drb-frontend/lib/c2api.ts
index 6b12dd2..dc87c93 100644
--- a/drb-frontend/lib/c2api.ts
+++ b/drb-frontend/lib/c2api.ts
@@ -25,8 +25,11 @@ export const c2api = {
   getNode: (id: string) => request<unknown>(`/nodes/${id}`),
   sendCommand: (nodeId: string, payload: object) =>
     request(`/nodes/${nodeId}/command`, { method: "POST", body: JSON.stringify(payload) }),
-  assignSystem: (nodeId: string, systemId: string) =>
-    request(`/nodes/${nodeId}/config/${systemId}`, { method: "POST" }),
+  assignSystem: (nodeId: string, systemId: string, hardwarePreset: string, ppmOverride?: number) => {
+    const params = new URLSearchParams({ hardware_preset: hardwarePreset });
+    if (ppmOverride !== undefined) params.set("ppm_override", String(ppmOverride));
+    return request(`/nodes/${nodeId}/config/${systemId}?${params}`, { method: "POST" });
+  },
 
   // Systems
   getSystems: () => request<unknown[]>("/systems"),
diff --git a/drb-frontend/lib/types.ts b/drb-frontend/lib/types.ts
index 7b38a8b..e6d6561 100644
--- a/drb-frontend/lib/types.ts
+++ b/drb-frontend/lib/types.ts
@@ -11,6 +11,8 @@ export interface NodeRecord {
   last_seen: string | null;
   assigned_system_id: string | null;
   approval_status: ApprovalStatus | null;
+  hardware_preset?: string;
+  ppm_override?: number | null;
 }
 
 export interface VocabularyPendingTerm {