fix(lora): update LoRa preset settings to reflect accurate BW, SF, and CR values; remove frequency from display

cmd/server/config.go

@@ -1023,8 +1023,8 @@ type AnalyticsConfig struct {
 	RecomputeIntervalSeconds map[string]int `json:"recomputeIntervalSeconds,omitempty"`
 	// LoRaPreset is the assumed PHY preset used by the relay-airtime-share
 	// metric to compute true Time-on-Air (issue #1768). Defaults to the
-	// EU MeshCore deployment: 869.6 MHz / BW 62.5 kHz / SF 8 / CR 4/5.
-	// freq is informational only and surfaces in the analytics caption.
+	// MeshCore deployment: BW 62.5 kHz / SF 7 / CR 4/5.
+	// freq is informational only and is not displayed or used in ToA.
 	LoRaPreset *LoRaPresetConfig `json:"loraPreset,omitempty"`
 }
 

cmd/server/relay_airtime_share.go

@@ -22,22 +22,21 @@ import (
 //
 // The PHY preset is config-driven (analytics.loraPreset in
 // config.example.json); defaults match the actual deployment
-// preset 869.6 MHz / BW 62.5 kHz / SF 8 / CR 4/5, with the
+// preset BW 62.5 kHz / SF 7 / CR 4/5, with the
 // SF-dependent preamble pulled from internal/lora.PreambleForSF.
 //
 // Aggregated by payload_type. Originator TX is deliberately excluded — a
 // never-relayed direct message scores 0, which is the correct framing for a
 // "relay amplification" metric. In-memory only; no SQL, no new index.
 
 // defaultLoRaPreset is the canonical fallback when config is absent.
-// Matches the reporter's `get radio` output `869.6179809, 62.5, 8, 5`.
+// Frequency does not affect ToA; it is kept only as an optional config field.
 func defaultLoRaPreset() lora.Preset {
 	return lora.Preset{
-		FreqHz:   869.6e6,
 		BWkHz:    62.5,
-		SF:       8,
+		SF:       7,
 		CR:       5,
-		Preamble: lora.PreambleForSF(8),
+		Preamble: lora.PreambleForSF(7),
 	}
 }
 

cmd/server/relay_airtime_share_test.go

@@ -97,7 +97,7 @@ func TestRelayAirtimeShare_ADVERTvsACKDivergence(t *testing.T) {
 	if !ok {
 		t.Fatalf("result['preset'] missing or wrong type: %T", result["preset"])
 	}
-	if preset.SF == 0 || preset.BWkHz == 0 || preset.CR == 0 || preset.Preamble == 0 || preset.FreqHz == 0 {
+	if preset.SF == 0 || preset.BWkHz == 0 || preset.CR == 0 || preset.Preamble == 0 {
 		t.Errorf("result['preset'] has zero fields: %+v", preset)
 	}
 
@@ -160,18 +160,18 @@ func TestRelayAirtimeShare_ADVERTvsACKDivergence(t *testing.T) {
 // gate: airtime_pct must follow true LoRa Time-on-Air, NOT bytes.
 //
 // Setup: 1 ADVERT (200 B, 1 relay) and 1 ACK (10 B, 1 relay) with the
-// default EU preset (869.6 MHz / BW 62.5 kHz / SF 8 / CR 4/5,
+// default US preset (BW 62.5 kHz / SF 7 / CR 4/5,
 // preamble 32 per firmware preambleLengthForSF).
 //
 // Old byte-proxy would give ADVERT 200/(200+10) = 95.24 %.
 // True ToA per #1768 closed form:
 //
-//	T_sym = 256 / 62500 = 4.096 ms
-//	ADVERT (PL=200): symbols = 36.25 + (8 + ceil((1600-32+44)/32)*5)
-//	               = 36.25 + (8 + 51*5) = 299.25 → 1225.728 ms
-//	ACK    (PL=10):  symbols = 36.25 + (8 + ceil((80-32+44)/32)*5)
-//	               = 36.25 + (8 + 3*5) = 59.25 → 242.688 ms
-//	ADVERT share = 1225.728 / (1225.728 + 242.688) = 0.83476 → 83.48 %
+//	T_sym = 128 / 62500 = 2.048 ms
+//	ADVERT (PL=200): symbols = 36.25 + (8 + ceil((1600-28+44)/28)*5)
+//	               = 36.25 + (8 + 58*5) = 334.25
+//	ACK    (PL=10):  symbols = 36.25 + (8 + ceil((80-28+44)/28)*5)
+//	               = 36.25 + (8 + 4*5) = 64.25
+//	ADVERT share = 334.25 / (334.25 + 64.25) = 0.83877 → 83.88 %
 //
 // 83 % vs 95 % is the whole point: small frames are no longer crushed
 // against large ones because the additive preamble + fixed-overhead
@@ -214,11 +214,11 @@ func TestRelayAirtimeShare_ToAReplacesByteProxy(t *testing.T) {
 	// Sanity guards on the independent calculation. Tolerances ±0.05 pp
 	// around the AN1200.13 hand-computed values keep this honest if the
 	// upstream lora package ever drifts.
-	if math.Abs(wantAdvert-83.4754) > 0.05 {
-		t.Fatalf("independent ADVERT ToA share drifted: got %.4f want ~83.4754", wantAdvert)
+	if math.Abs(wantAdvert-83.8770) > 0.05 {
+		t.Fatalf("independent ADVERT ToA share drifted: got %.4f want ~83.8770", wantAdvert)
 	}
-	if math.Abs(wantAck-16.5246) > 0.05 {
-		t.Fatalf("independent ACK ToA share drifted: got %.4f want ~16.5246", wantAck)
+	if math.Abs(wantAck-16.1230) > 0.05 {
+		t.Fatalf("independent ACK ToA share drifted: got %.4f want ~16.1230", wantAck)
 	}
 	if math.Abs(advertPct-wantAdvert) > 0.2 {
 		t.Errorf("ADVERT airtime_pct = %.4f, want %.4f (true ToA)", advertPct, wantAdvert)

config.example.json

@@ -425,11 +425,10 @@
       "nodesClockSkew": 300
     },
     "loraPreset": {
-      "freq": 869600000,
       "bw": 62.5,
-      "sf": 8,
+      "sf": 7,
       "cr": 5,
-      "_comment_": "Issue #1768. LoRa PHY preset assumed by the Relay Airtime Share metric to compute true Time-on-Air. Share numbers are only meaningful relative to one preset, so operators MUST set this to match their mesh — freq is informational (surfaces in the chart caption) and does not affect ToA; bw is bandwidth in kHz (e.g. 62.5, 125, 250); sf is spreading factor (6..12); cr is the denominator of the 4/N coding rate (5 ⇒ 4/5 … 8 ⇒ 4/8). Defaults reproduce the typical EU MeshCore deployment 869.6 MHz / BW 62.5 kHz / SF 8 / CR 4/5. CRC=1, IH=0, DE (T_sym ≥ 16 ms), and preamble (32 for SF≤8, 16 otherwise, per firmware preambleLengthForSF) are firmware-fixed and intentionally not exposed as config."
+      "_comment_": "Issue #1768. LoRa PHY preset assumed by the Relay Airtime Share metric to compute true Time-on-Air. Share numbers are only meaningful relative to one preset, so operators MUST set this to match their mesh — freq is optional, informational only, and neither displayed nor used in ToA; bw is bandwidth in kHz (e.g. 62.5, 125, 250); sf is spreading factor (6..12); cr is the denominator of the 4/N coding rate (5 ⇒ 4/5 … 8 ⇒ 4/8). Defaults: BW 62.5 kHz / SF 7 / CR 4/5. CRC=1, IH=0, DE (T_sym ≥ 16 ms), and preamble (32 for SF≤8, 16 otherwise, per firmware preambleLengthForSF) are firmware-fixed and intentionally not exposed as config."
     }
   },
   "_comment_analytics": "Issue #1240 + #1256 + #1265. Each analytics endpoint (topology, rf, distance, channels, hashCollisions, hashSizes, roles, observersClockSkew, nodesClockSkew) is recomputed in the background on the configured interval and served from an atomic-pointer cache. Reads never block on compute. Default 300s (5 min) per endpoint reflects the operator principle: serving slightly stale data quickly beats real-time data slowly. Lower values = fresher data at higher CPU cost. Only the default query (no region/window) is precomputed; region- and window-filtered requests fall back to the legacy on-request compute + 60s TTL cache.",

public/analytics.js

@@ -521,13 +521,11 @@
     var preset = data && data.preset;
     var presetCaption = '';
     if (preset && typeof preset === 'object') {
-      var freqMHz = Number(preset.freq_hz || 0) / 1e6;
       var bwKhz = Number(preset.bw_khz || 0);
       var bwStr = bwKhz ? bwKhz.toFixed(1).replace(/\.0$/, '') : '0';
       presetCaption =
         '<div class="dumbbell-preset text-muted" style="font-size:11px;padding:0 4px 6px 4px">' +
         'Assumed LoRa preset: ' +
-        (freqMHz ? esc(freqMHz.toFixed(3)) + ' MHz / ' : '') +
         'BW ' + esc(bwStr) + ' kHz / ' +
         'SF ' + esc(String(Number(preset.sf || 0))) + ' / ' +
         'CR 4/' + esc(String(Number(preset.cr || 0))) +
@@ -3175,6 +3173,7 @@ function destroy() { _stopRolesRefresh(); _stopScopesRefresh(); _stopDistanceRet
     window._analyticsRetransmissionBucketFor = retransmissionBucketFor;
     window._analyticsRenderRetransmissionChart = renderRetransmissionChart;
     window._analyticsScopeAdvertsByRoleHtml = scopeAdvertsByRoleHtml;
+    window._analyticsRenderRelayAirtimeDumbbell = renderRelayAirtimeDumbbell;
   }
 
   // ─── Neighbor Graph Tab ─────────────────────────────────────────────────────

tests/unit/test-frontend-helpers.js

@@ -6937,6 +6937,31 @@ console.log('\n=== map.js: hash size fallback ===');
   });
 }
 
+// ===== analytics.js: Relay Airtime Share preset caption (#189) =====
+console.log('\n=== analytics.js: renderRelayAirtimeDumbbell preset caption ===');
+{
+  const ctx = makeSandbox();
+  loadInCtx(ctx, 'public/roles.js');
+  loadInCtx(ctx, 'public/app.js');
+  try { loadInCtx(ctx, 'public/analytics.js'); } catch (e) { /* IIFE side-effects ok */ }
+  const render = ctx.window._analyticsRenderRelayAirtimeDumbbell;
+  test('renderRelayAirtimeDumbbell is exposed', () => assert.ok(render));
+  if (render) {
+    const data = {
+      total_score: 10,
+      rows: [{ payload_type: 'ADVERT', count: 1, count_pct: 50, airtime_pct: 50, score: 5 }],
+      preset: { freq_hz: 869600000, bw_khz: 62.5, sf: 7, cr: 5, preamble: 32 },
+    };
+    test('caption shows BW / SF / CR but never the frequency (#189)', () => {
+      const html = render(data);
+      assert.ok(html.includes('BW 62.5 kHz'), 'BW missing');
+      assert.ok(html.includes('SF 7'), 'SF missing');
+      assert.ok(html.includes('CR 4/5'), 'CR missing');
+      assert.ok(!/MHz/.test(html), 'frequency must not be displayed: ' + html);
+    });
+  }
+}
+
 // ===== SUMMARY =====
 Promise.allSettled(pendingTests).then(() => {
   console.log(`\n${'═'.repeat(40)}`);