diff --git a/main/dsp.c b/main/dsp.c
index 6ba9abdaa96af5b12085cf7b310dd6bde8e48de6..4ad255c3fe89b8b987451262d057a73b1c2b47bf 100644
--- a/main/dsp.c
+++ b/main/dsp.c
@@ -312,7 +312,6 @@ static inline void goertzel_sample(goertzel_state_t *s, short sample)
 		s->chunky++;
 		s->v3 = s->v3 >> 1;
 		s->v2 = s->v2 >> 1;
-		v1 = v1 >> 1;
 	}
 }
 
@@ -503,7 +502,7 @@ static void ast_mf_detect_init (mf_detect_state_t *s, unsigned int sample_rate)
 	int i;
 	s->hits[0] = s->hits[1] = s->hits[2] = s->hits[3] = s->hits[4] = 0;
 	for (i = 0;  i < 6;  i++) {
-		goertzel_init (&s->tone_out[i], mf_tones[i], 160, sample_rate);
+		goertzel_init (&s->tone_out[i], mf_tones[i], MF_SIZE, sample_rate);
 	}
 	s->current_sample = 0;
 	s->current_hit = 0;