diff --git a/include/rtctime.h b/include/rtctime.h
index 5b8672e9..479ac557 100644
--- a/include/rtctime.h
+++ b/include/rtctime.h
@@ -22,6 +22,7 @@ time_t get_rtctime(void);
 float get_rtctemp(void);
 void IRAM_ATTR CLOCKIRQ();
 int pps_init(uint32_t pps_freq);
+int pps_init();
 void pps_start();
 uint8_t sync_clock(time_t t);
 
diff --git a/src/dcf77.cpp b/src/dcf77.cpp
index 8cc2313c..29182a5f 100644
--- a/src/dcf77.cpp
+++ b/src/dcf77.cpp
@@ -6,11 +6,7 @@ https://www-user.tu-chemnitz.de/~heha/viewzip.cgi/hs/Funkuhr.zip/
 //
 */
 
-#ifdef HAS_DCF77
-
-#ifdef IF_482
-#error  "You must define at most one of IF482 or DCF_77"
-#endif
+#if defined HAS_DCF77
 
 #include "dcf77.h"
 
@@ -19,11 +15,6 @@ static const char TAG[] = "main";
 
 #define DCF77_FRAME_SIZE (60)
 #define DCF77_PULSE_DURATION (100)
-#ifdef RTC_CLK
-#define PPS (RTC_CLK / DCF77_PULSE_DURATION)
-#else
-#define PPS DCF77_PULSE_DURATION
-#endif
 
 // array of dcf pulses for three minutes
 uint8_t DCFtimeframe[DCF77_FRAME_SIZE];
@@ -46,7 +37,12 @@ int dcf77_init(void) {
 
   assert(ClockTask); // has clock task started?
 
-  pps_init(PPS);              // setup pulse
+#if defined RTC_INT && (RTC_CLK == DCF77_PULSE_DURATION)
+  pps_init(); // use pps clock
+#else
+  pps_init(DCF77_PULSE_DURATION); // use esp32 clock
+#endif
+
   DCF_Out(sync_clock(now())); // sync DCF time on next second
   pps_start();                // start pulse
 
@@ -122,10 +118,10 @@ void dcf77_loop(void *pvParameters) {
         &wakeTime,      // receives moment of call from isr
         portMAX_DELAY); // wait forever (missing error handling here...)
 
-#if (PPS == DCF77_PULSE_DURATION) // we don't need clock rescaling
+#if !defined RTC_CLK || (RTC_CLK == DCF77_PULSE_DURATION) // we don't need clock rescaling
     DCF_Out(0);
 #else // we need clock rescaling by software timer
-    for (uint8_t i = 1; i <= PPS; i++) {
+    for (uint8_t i = 1; i <= RTC_CLK / DCF77_PULSE_DURATION; i++) {
       DCF_Out(0);
       vTaskDelayUntil(&wakeTime, pdMS_TO_TICKS(DCF77_PULSE_DURATION));
     }
diff --git a/src/if482.cpp b/src/if482.cpp
index 41ac2834..da582716 100644
--- a/src/if482.cpp
+++ b/src/if482.cpp
@@ -1,3 +1,5 @@
+#if defined HAS_IF482
+
 /* NOTE:
 The IF482 Generator needs an high precise 1 Hz clock signal which cannot be
 acquired in suitable precision on the ESP32 SoC itself. Additional clocking
@@ -77,12 +79,6 @@ not evaluated by model BU-190
 */
 ///////////////////////////////////////////////////////////////////////////////
 
-#ifdef HAS_IF482
-
-#ifdef HAS_DCF77
-#error "You must define at most one of IF482 or DCF_77"
-#endif
-
 #include "if482.h"
 
 // Local logging tag
@@ -90,11 +86,6 @@ static const char TAG[] = "main";
 
 #define IF482_FRAME_SIZE (17)
 #define IF482_PULSE_DURATION (1000)
-#ifdef RTC_CLK
-#define PPS (RTC_CLK / IF482_PULSE_DURATION)
-#else
-#define PPS IF482_PULSE_DURATION
-#endif
 
 HardwareSerial IF482(2); // use UART #2 (note: #1 may be in use for serial GPS)
 
@@ -115,8 +106,13 @@ int if482_init(void) {
 
   assert(ClockTask); // has clock task started?
 
-  pps_init(PPS); // setup pulse
-  pps_start();   // start pulse
+#if defined RTC_INT && (RTC_CLK == IF482_PULSE_DURATION)
+  pps_init(); // use pps clock
+#else
+  pps_init(IF482_PULSE_DURATION); // use esp32 clock
+#endif
+
+  pps_start(); // start pulse
 
   return 1; // success
 } // if482_init
@@ -174,14 +170,15 @@ void if482_loop(void *pvParameters) {
         &wakeTime,      // receives moment of call from isr
         portMAX_DELAY); // wait forever (missing error handling here...)
 
-#if (PPS == DCF77_PULSE_DURATION) // we don't need clock rescaling
+#if !defined RTC_CLK || (RTC_CLK == IF482_PULSE_DURATION) // we don't need clock rescaling
     // wait until it's time to start transmit telegram for next second
     vTaskDelayUntil(&wakeTime, shotTime); // sets waketime to moment of shot
     IF482.print(IF482_Out(now() + 1));
+
 #else // we need clock rescaling by software timer
-    /*
-    not yet implemented for IF482
-    */
+                                 /*
+                                 not yet implemented for IF482
+                                 */
 #endif
   }
 } // if482_loop()
diff --git a/src/main.cpp b/src/main.cpp
index b2ce3336..288c5e61 100644
--- a/src/main.cpp
+++ b/src/main.cpp
@@ -65,7 +65,7 @@ char display_line6[16], display_line7[16]; // display buffers
 uint8_t volatile channel = 0;              // channel rotation counter
 uint16_t volatile macs_total = 0, macs_wifi = 0, macs_ble = 0,
                   batt_voltage = 0; // globals for display
-bool volatile BitsPending = false;  // DCF77 or IF482 ticker indicator
+bool volatile BitsPending = false; // DCF77 or IF482 ticker indicator
 
 hw_timer_t *sendCycle = NULL, *homeCycle = NULL;
 #ifdef HAS_DISPLAY
@@ -416,7 +416,9 @@ void setup() {
   setSyncInterval(TIME_SYNC_INTERVAL_GPS * 60);
 #endif
 
-#ifdef HAS_IF482
+#if (defined HAS_IF482) && (defined DCF_77)
+#error "You may define at most one of HAS_IF482 or DCF_77"
+#elif defined HAS_IF482
   ESP_LOGI(TAG, "Starting IF482 Generator...");
   assert(if482_init());
 #elif defined HAS_DCF77
diff --git a/src/rtctime.cpp b/src/rtctime.cpp
index 5c08af77..bd2ae503 100644
--- a/src/rtctime.cpp
+++ b/src/rtctime.cpp
@@ -1,15 +1,15 @@
+#ifdef HAS_RTC
+
 #include "rtctime.h"
 
 // Local logging tag
 static const char TAG[] = "main";
 
+RtcDS3231<TwoWire> Rtc(Wire); // RTC hardware i2c interface
+
 TaskHandle_t ClockTask;
 hw_timer_t *clockCycle = NULL;
 
-#ifdef HAS_RTC // we have hardware RTC
-
-RtcDS3231<TwoWire> Rtc(Wire); // RTC hardware i2c interface
-
 // initialize RTC
 int rtc_init(void) {
 
@@ -100,11 +100,9 @@ float get_rtctemp(void) {
   return 0;
 } // get_rtctemp()
 
-#endif // HAS_RTC
-
-int pps_init(uint32_t clk_freq_Hz) {
-// use fixed pulse clock as time base
-#if defined RTC_INT && (RTC_CLK == clk_freq_Hz)
+int pps_init() {
+// we have hardware pps signal as time base
+#if defined RTC_INT && defined RTC_CLK
 
   // setup external interupt for active low RTC INT pin
   pinMode(RTC_INT, INPUT_PULLUP);
@@ -120,20 +118,21 @@ int pps_init(uint32_t clk_freq_Hz) {
     return 0; // failure
   }
   return 1; // success
+#endif
+}
 
-#else
-  // use clock with adjustable frequency
-  if (clk_freq_Hz) {
+int pps_init(uint32_t pps_freq) {
+  // if we don't have hardware pps we use ESP32 hardware timer
+  if (pps_freq) {
     ESP_LOGI(TAG, "Time base ESP32 clock");
     clockCycle = timerBegin(1, 8000, true); // set 80 MHz prescaler
     timerAttachInterrupt(clockCycle, &CLOCKIRQ, true);
-    timerAlarmWrite(clockCycle, 100 * clk_freq_Hz, true);
+    timerAlarmWrite(clockCycle, 10 * pps_freq, true);
   } else {
-    ESP_LOGE(TAG, "Invalid pulse clock frequency");
+    ESP_LOGE(TAG, "Invalid pps clock frequency");
     return 0; // failure
   }
   return 1; // success
-#endif
 }
 
 void pps_start() {
@@ -160,4 +159,6 @@ uint8_t sync_clock(time_t t) {
 void IRAM_ATTR CLOCKIRQ() {
   xTaskNotifyFromISR(ClockTask, xTaskGetTickCountFromISR(), eSetBits, NULL);
   portYIELD_FROM_ISR();
-}
\ No newline at end of file
+}
+
+#endif // HAS_RTC
\ No newline at end of file