From 95e0309c632871ad451cf71ce3751d801eac5c83 Mon Sep 17 00:00:00 2001
From: Smittix <jamessmith1@outlook.com>
Date: Thu, 15 Jan 2026 23:02:52 +0000
Subject: [PATCH] Add configurable 8.33 kHz channel spacing for airband

When using custom frequency, a spacing selector appears allowing
choice between 25 kHz (standard) and 8.33 kHz (European) channel
spacing. The frequency step adjusts accordingly.

Co-Authored-By: Claude Opus 4.5 <noreply@anthropic.com>
---
 templates/adsb_dashboard.html | 21 ++++++++++++++++++++-
 1 file changed, 20 insertions(+), 1 deletion(-)

diff --git a/templates/adsb_dashboard.html b/templates/adsb_dashboard.html
index 2cb4731..3baaccd 100644
--- a/templates/adsb_dashboard.html
+++ b/templates/adsb_dashboard.html
@@ -254,7 +254,11 @@
                         <option value="134.725">134.725</option>
                         <option value="custom">Custom...</option>
                     </select>
-                    <input type="number" id="airbandCustomFreq" step="0.005" placeholder="MHz" class="airband-controls" style="width: 65px; display: none;">
+                    <input type="number" id="airbandCustomFreq" step="0.025" placeholder="MHz" class="airband-controls" style="width: 65px; display: none;">
+                    <select id="airbandSpacing" class="airband-controls" title="Channel spacing" style="width: 55px; display: none;" onchange="updateAirbandSpacing()">
+                        <option value="25">25 kHz</option>
+                        <option value="8.33">8.33 kHz</option>
+                    </select>
                     <select id="airbandDeviceSelect" class="airband-controls" title="SDR for airband">
                         <option value="0">SDR 0</option>
                     </select>
@@ -3056,10 +3060,13 @@ sudo make install</code>
         function updateAirbandFreq() {
             const select = document.getElementById('airbandFreqSelect');
             const customInput = document.getElementById('airbandCustomFreq');
+            const spacingSelect = document.getElementById('airbandSpacing');
             if (select.value === 'custom') {
                 customInput.style.display = 'inline-block';
+                spacingSelect.style.display = 'inline-block';
             } else {
                 customInput.style.display = 'none';
+                spacingSelect.style.display = 'none';
                 // If audio is playing, restart on new frequency
                 if (isAirbandPlaying) {
                     stopAirband();
@@ -3068,6 +3075,18 @@ sudo make install</code>
             }
         }
 
+        function updateAirbandSpacing() {
+            const spacing = document.getElementById('airbandSpacing').value;
+            const customInput = document.getElementById('airbandCustomFreq');
+            if (spacing === '8.33') {
+                // 8.33 kHz = 0.00833 MHz
+                customInput.step = '0.00833';
+            } else {
+                // 25 kHz = 0.025 MHz
+                customInput.step = '0.025';
+            }
+        }
+
         // Handle custom frequency input changes
         document.addEventListener('DOMContentLoaded', () => {
             const customInput = document.getElementById('airbandCustomFreq');