Using light and sound sources at night to determine distance:
??You can see cigarette butts and fire within 1km;
??You can see matches within 1.5km The light of fire and flashlight;
??The fire of the rifle can be seen within 2 kilometers;
??The normal conversation can be heard within 0.5 kilometers;
??You can hear people’s shouts within 1.5 kilometers;
??You can hear the sound of cars and horses’ hoofs within 1 kilometers;
??In 2 kilometers Car horns can be heard within 5 kilometers;
??Guns can be heard within 5 kilometers
