diff --git a/src/wspr.c b/src/wspr.c
--- a/src/wspr.c
+++ b/src/wspr.c
@@ -59,7 +59,7 @@ void wspr_transmit(uint8_t* grid_locator
     // Start timer for WSPR
     __TIM1_CLK_ENABLE();
     htim1.Instance = TIM1;
-    htim1.Init.Prescaler = 512; // gives 64uS ticks from 8MHz ahbclk
+    htim1.Init.Prescaler = 512 / 4; // FIXED gives 64us ticks from 2mhz clock // gives 64uS ticks from 8MHz ahbclk
     htim1.Init.CounterMode = TIM_COUNTERMODE_UP;
     htim1.Init.Period = ctc; // Count up to this value (how many 64uS ticks per symbol)
     htim1.Init.ClockDivision = TIM_CLOCKDIVISION_DIV1;