feat(lora): warn when selecting a licensed amateur-radio region (#3924)

public/locales/en.json

@@ -3189,6 +3189,7 @@
   "lora_config.override_frequency_description": "HAM/Advanced: Override channel calculation and use this frequency. Frequency offset still applies. Value of 0 = disabled",
   "lora_config.region": "Region Code",
   "lora_config.region_description": "Select your regulatory region for frequency/power limits",
+  "lora_config.amateur_band_warning": "This region operates in a licensed amateur (ham) radio band. A valid amateur radio license is required, and you are responsible for complying with local band-plan, power, and station identification rules.",
   "lora_config.hop_limit": "Hop Limit",
   "lora_config.hop_limit_description": "Maximum number of hops for mesh packets. Range: 1-7 (default: 3)",
   "lora_config.tx_power": "Transmit Power (dBm)",

src/components/admin-commands/RadioConfigurationSection.tsx

@@ -1,6 +1,6 @@
 import React from 'react';
 import { useTranslation } from 'react-i18next';
-import { MODEM_PRESET_OPTIONS, REGION_OPTIONS } from '../configuration/constants';
+import { MODEM_PRESET_OPTIONS, REGION_OPTIONS, isAmateurRadioRegion } from '../configuration/constants';
 import type { Channel } from '../../types/device';
 
 interface RadioConfigurationSectionProps {
@@ -214,6 +214,23 @@ export const RadioConfigurationSection: React.FC<RadioConfigurationSectionProps>
               </option>
             ))}
           </select>
+          {isAmateurRadioRegion(region) && (
+            <div
+              role="alert"
+              className="setting-description"
+              style={{
+                marginTop: '0.5rem',
+                padding: '0.6rem 0.75rem',
+                border: '1px solid var(--ctp-yellow)',
+                borderRadius: '4px',
+                backgroundColor: 'rgba(249, 226, 175, 0.12)',
+                color: 'var(--ctp-yellow)',
+                lineHeight: '1.4'
+              }}
+            >
+              ⚠️ {t('lora_config.amateur_band_warning')}
+            </div>
+          )}
         </div>
         <div className="setting-item">
           <label>Hop Limit (1-7)</label>

src/components/configuration/LoRaConfigSection.test.tsx

@@ -1,5 +1,5 @@
 import { describe, it, expect } from 'vitest';
-import { MODEM_PRESET_OPTIONS, FEM_LNA_MODE_OPTIONS } from './constants';
+import { MODEM_PRESET_OPTIONS, FEM_LNA_MODE_OPTIONS, AMATEUR_RADIO_REGIONS, isAmateurRadioRegion, REGION_MAP } from './constants';
 
 /**
  * LoRaConfigSection Tests
@@ -137,6 +137,40 @@ describe('LoRaConfigSection', () => {
     });
   });
 
+  describe('Amateur Radio Region Warning (#3924)', () => {
+    it('flags the ITU 2m amateur regions (27, 28) as amateur bands', () => {
+      expect(isAmateurRadioRegion(27)).toBe(true); // ITU1_2M
+      expect(isAmateurRadioRegion(28)).toBe(true); // ITU23_2M
+    });
+
+    it('keeps the amateur region set in sync with REGION_MAP values', () => {
+      expect(AMATEUR_RADIO_REGIONS[27]).toBe('ITU1_2M');
+      expect(AMATEUR_RADIO_REGIONS[28]).toBe('ITU23_2M');
+      expect(REGION_MAP['ITU1_2M']).toBe(27);
+      expect(REGION_MAP['ITU23_2M']).toBe(28);
+    });
+
+    it('does not flag standard ISM/SRD regions as amateur bands', () => {
+      expect(isAmateurRadioRegion(1)).toBe(false); // US
+      expect(isAmateurRadioRegion(3)).toBe(false); // EU_868
+      expect(isAmateurRadioRegion(6)).toBe(false); // ANZ
+      expect(isAmateurRadioRegion(32)).toBe(false); // EU_N_868
+    });
+
+    it('does not flag UNSET (0) as an amateur band', () => {
+      expect(isAmateurRadioRegion(0)).toBe(false);
+    });
+
+    it('handles null/undefined region without throwing', () => {
+      expect(isAmateurRadioRegion(null)).toBe(false);
+      expect(isAmateurRadioRegion(undefined)).toBe(false);
+    });
+
+    it('does not flag an out-of-range region value', () => {
+      expect(isAmateurRadioRegion(999)).toBe(false);
+    });
+  });
+
   describe('Save Configuration Logic', () => {
     it('includes femLnaMode in the LoRa save payload', () => {
       // Mirrors the Device Configuration save (ConfigurationTab) and Remote Admin

src/components/configuration/LoRaConfigSection.tsx

@@ -1,6 +1,6 @@
 import React, { useState, useRef, useMemo, useCallback } from 'react';
 import { useTranslation } from 'react-i18next';
-import { MODEM_PRESET_OPTIONS, REGION_OPTIONS, FEM_LNA_MODE_OPTIONS } from './constants';
+import { MODEM_PRESET_OPTIONS, REGION_OPTIONS, FEM_LNA_MODE_OPTIONS, isAmateurRadioRegion } from './constants';
 import { useSaveBar } from '../../hooks/useSaveBar';
 
 interface LoRaConfigSectionProps {
@@ -387,6 +387,23 @@ const LoRaConfigSection: React.FC<LoRaConfigSectionProps> = ({
             </option>
           ))}
         </select>
+        {isAmateurRadioRegion(region) && (
+          <div
+            role="alert"
+            className="setting-description"
+            style={{
+              marginTop: '0.5rem',
+              padding: '0.6rem 0.75rem',
+              border: '1px solid var(--ctp-yellow, #f9e2af)',
+              borderRadius: '4px',
+              backgroundColor: 'rgba(249, 226, 175, 0.12)',
+              color: 'var(--ctp-yellow, #f9e2af)',
+              lineHeight: '1.4'
+            }}
+          >
+            ⚠️ {t('lora_config.amateur_band_warning')}
+          </div>
+        )}
       </div>
       <div className="setting-item">
         <label htmlFor="hopLimit">

src/components/configuration/constants.ts

@@ -124,6 +124,42 @@ export const REGION_OPTIONS: RegionOption[] = [
   { value: 32, label: 'EU_N_868 - European Union 868MHz Narrow' }
 ];
 
+// Licensed amateur-radio LoRa regions.
+//
+// The ITU amateur-radio RegionCode entries map onto the 2m amateur band
+// (144-148 MHz), which is licensed spectrum in every ITU region. Operating a
+// Meshtastic node on one of these regions legally requires a valid amateur
+// radio license, and the operator is responsible for complying with local
+// band-plan and identification rules. The LoRa config UI surfaces a warning
+// when one of these regions is selected.
+//
+// Values mirror Config.LoRaConfig.RegionCode (meshtastic/protobufs config.proto):
+//   27 = ITU1_2M   (ITU Region 1 amateur 2m, 144-146 MHz)
+//   28 = ITU23_2M  (ITU Region 2/3 amateur 2m, 144-148 MHz)
+//
+// NOTE: Firmware 2.8 introduces a region -> preset legality map (sent once by
+// the device) that the official mobile apps use to filter the preset picker to
+// presets that are legal for the selected region. MeshMonitor cannot consume
+// that map yet because the vendored protobufs (v2.7.26) predate it; when the
+// protobuf submodule is bumped to a 2.8 release this list can be replaced by
+// the device-reported legality data. See issue #3924.
+export const AMATEUR_RADIO_REGIONS: Record<number, string> = {
+  27: 'ITU1_2M',
+  28: 'ITU23_2M'
+};
+
+/**
+ * Returns true when the given RegionCode value corresponds to a licensed
+ * amateur-radio band (an ITU 2m region). Used to surface a compliance warning
+ * in the LoRa configuration UI.
+ */
+export function isAmateurRadioRegion(region: number | null | undefined): boolean {
+  if (region === null || region === undefined) {
+    return false;
+  }
+  return Object.prototype.hasOwnProperty.call(AMATEUR_RADIO_REGIONS, region);
+}
+
 // Config.LoRaConfig.FEM_LNA_Mode (firmware >= v2.7.20, meshtastic/firmware#9809).
 // Value 0 (DISABLED) is the proto3 zero/default and a real selectable mode.
 export const FEM_LNA_MODE_OPTIONS: RegionOption[] = [