diff --git a/main.c b/main.c
index 7c2d352..5327b2f 100644
--- a/main.c
+++ b/main.c
@@ -375,7 +375,7 @@ config_t config = {
   /* menu_active_color */ 0x7777,
   /* trace_colors[4] */ { RGB565(0,255,255), RGB565(255,0,40), RGB565(0,0,255), RGB565(50,255,0) },
   ///* touch_cal[4] */ { 620, 600, 160, 190 },
-  /* touch_cal[4] */ { 620, 600, 130, 180 },
+  /* touch_cal[4] */ { 693, 605, 124, 171 },
   /* default_loadcal */    0,
   /* checksum */           0
 };
@@ -546,6 +546,8 @@ set_sweep_frequency(int type, float frequency)
     freq_mode_startstop();
     if (frequency < START_MIN)
       freq = START_MIN;
+    if (frequency > STOP_MAX)
+      freq = STOP_MAX;
     if (frequency0 != freq) {
       ensure_edit_config();
       frequency0 = freq;
@@ -559,6 +561,8 @@ set_sweep_frequency(int type, float frequency)
     freq_mode_startstop();
     if (frequency > STOP_MAX)
       freq = STOP_MAX;
+    if (frequency < START_MIN)
+      freq = START_MIN;
     if (frequency1 != freq) {
       ensure_edit_config();
       frequency1 = freq;
@@ -1228,6 +1232,18 @@ static void cmd_touchcal(BaseSequentialStream *chp, int argc, char *argv[])
   touch_start_watchdog();
 }
 
+static void cmd_touchtest(BaseSequentialStream *chp, int argc, char *argv[])
+{
+  (void)chp;
+  (void)argc;
+  (void)argv;
+  chMtxLock(&mutex);
+  do {
+    touch_draw_test();
+  } while(argc);
+  chMtxUnlock(&mutex);
+}
+
 static void cmd_frequencies(BaseSequentialStream *chp, int argc, char *argv[])
 {
   int i;
@@ -1388,6 +1404,7 @@ static const ShellCommand commands[] =
     { "sweep", cmd_sweep },
     { "test", cmd_test },
     { "touchcal", cmd_touchcal },
+    { "touchtest", cmd_touchtest },
     { "pause", cmd_pause },
     { "resume", cmd_resume },
     { "cal", cmd_cal },
diff --git a/nanovna.h b/nanovna.h
index b8ac09d..76cf74a 100644
--- a/nanovna.h
+++ b/nanovna.h
@@ -307,6 +307,7 @@ void handle_touch_interrupt(void);
 #define TOUCH_THRESHOLD 2000
 
 void touch_cal_exec(void);
+void touch_draw_test(void);
 
 /*
  * adc.c
diff --git a/ui.c b/ui.c
index 4a69dd4..e82aac1 100644
--- a/ui.c
+++ b/ui.c
@@ -196,9 +196,9 @@ touch_measure_y(void)
 
   chThdSleepMilliseconds(2);
   v = adc_single_read(ADC1, ADC_CHSELR_CHSEL7);
-  chThdSleepMilliseconds(2);
-  v += adc_single_read(ADC1, ADC_CHSELR_CHSEL7);
-  return v/2;
+  //chThdSleepMilliseconds(2);
+  //v += adc_single_read(ADC1, ADC_CHSELR_CHSEL7);
+  return v;
 }
 
 int
@@ -216,9 +216,9 @@ touch_measure_x(void)
 
   chThdSleepMilliseconds(2);
   v = adc_single_read(ADC1, ADC_CHSELR_CHSEL6);
-  chThdSleepMilliseconds(2);
-  v += adc_single_read(ADC1, ADC_CHSELR_CHSEL6);
-  return v/2;
+  //chThdSleepMilliseconds(2);
+  //v += adc_single_read(ADC1, ADC_CHSELR_CHSEL6);
+  return v;
 }
 
 void
@@ -252,8 +252,13 @@ int touch_check(void)
 {
   int stat = touch_status();
   if (stat) {
-    last_touch_x = touch_measure_x();
-    last_touch_y = touch_measure_y();
+    chThdSleepMilliseconds(10);
+    int x = touch_measure_x();
+    int y = touch_measure_y();
+    if (touch_status()) {
+      last_touch_x = x;
+      last_touch_y = y;
+    }
     touch_prepare_sense();
   }
 
@@ -289,12 +294,20 @@ touch_cal_exec(void)
   
   adc_stop(ADC1);
 
+  ili9341_fill(0, 0, 320, 240, 0);
+  ili9341_line(0, 0, 0, 32, 0xffff);
+  ili9341_line(0, 0, 32, 0, 0xffff);
+
   do {
     status = touch_check();
   } while(status != EVT_TOUCH_PRESSED);
   x1 = last_touch_x;
   y1 = last_touch_y;
 
+  ili9341_fill(0, 0, 320, 240, 0);
+  ili9341_line(320-1, 240-1, 320-1, 240-32, 0xffff);
+  ili9341_line(320-1, 240-1, 320-32, 240-1, 0xffff);
+
   do {
     status = touch_check();
   } while(status != EVT_TOUCH_PRESSED);
@@ -305,8 +318,38 @@ touch_cal_exec(void)
   config.touch_cal[1] = y1;
   config.touch_cal[2] = (x2 - x1) * 16 / 320;
   config.touch_cal[3] = (y2 - y1) * 16 / 240;
+
+  touch_start_watchdog();
+  redraw_all();
+}
+
+void
+touch_draw_test(void)
+{
+  int status;
+  int x0, y0;
+  int x1, y1;
+  
+  adc_stop(ADC1);
+
+  do {
+    status = touch_check();
+  } while(status != EVT_TOUCH_PRESSED);
+  touch_position(&x0, &y0);
+
+  do {
+    status = touch_check();
+    touch_position(&x1, &y1);
+    ili9341_line(x0, y0, x1, y1, 0xffff);
+    x0 = x1;
+    y0 = y1;
+    chThdSleepMilliseconds(50);
+  } while(status != EVT_TOUCH_RELEASED);
+
+  touch_start_watchdog();
 }
 
+
 void
 touch_position(int *x, int *y)
 {
@@ -1233,7 +1276,9 @@ void drag_marker(int t, int m)
     int touch_x, touch_y;
     int index;
     touch_position(&touch_x, &touch_y);
-    index = search_nearest_index(touch_x + OFFSETX, touch_y + OFFSETY, t);
+    touch_x -= OFFSETX;
+    touch_y -= OFFSETY;
+    index = search_nearest_index(touch_x, touch_y, t);
     if (index >= 0) {
       markers[m].index = index;
       redraw_marker(m, TRUE);
@@ -1255,8 +1300,8 @@ touch_pickup_marker(void)
   int touch_x, touch_y;
   int m, t;
   touch_position(&touch_x, &touch_y);
-  touch_x += OFFSETX;
-  touch_y += OFFSETY;
+  touch_x -= OFFSETX;
+  touch_y -= OFFSETY;
 
   for (m = 0; m < 4; m++) {
     if (!markers[m].enabled)