lock ap channel for faster reconnect

src/main.cpp

@@ -106,6 +106,7 @@ unsigned long lastSuccess = 0;
 IPAddress ip, dns, gateway, subnet;
 char ssid[64];
 char password[64];
+int32_t channel;
 
 struct __attribute__((packed)) SENSOR_DATA {
   float temperature;
@@ -282,6 +283,8 @@ void ICACHE_FLASH_ATTR sendValues() {
   WiFi.forceSleepWake();
   delay(1);  // yield();
   WiFi.mode(WIFI_STA);
+  //wifi_country_t wc = { .cc="DE", .schan=1, .nchan=13, .policy=WIFI_COUNTRY_POLICY_AUTO};
+  //wifi_set_country(&wc);
 
   if ( ip != INADDR_NONE && dns != INADDR_NONE && gateway != INADDR_NONE && subnet != INADDR_NONE
        && ((ip[0] == 192 && ip[1] == 168) || (ip[0] == 172 && ip[1] == 16))
@@ -291,7 +294,7 @@ void ICACHE_FLASH_ATTR sendValues() {
 
     DEBUG_MSG("[WiFi] STATIC IP\n");
     WiFi.config(ip, dns, gateway, subnet);
-    WiFi.begin(ssid, password);
+    WiFi.begin(ssid, password, channel);
     int tries = 0;
     constexpr unsigned int retry_delay = 500;
     constexpr unsigned int max_retry_delay = 10000;
@@ -335,6 +338,7 @@ void ICACHE_FLASH_ATTR sendValues() {
     subnet = WiFi.subnetMask();
     strncpy(ssid, WiFi.SSID().c_str(), 64);
     strncpy(password, WiFi.psk().c_str(), 64);
+    channel = WiFi.channel();
     last_dhcp = rtcMillis();
   }