In this experiment was achieved a measured distance of 9.24 meters. The method that increases the range is using a parabolic dash to reduce the ‘field of view’ (FOV) of the basic sensor. You have at least one option to increase the measurement range of the sensors. The HC-SR04 sensor provides 2cm to 400cm non-contact measurement function.
But in this article, the author compare it with two other ultrasonic sensors and give a brief overview of the differences and how to write the program that reads values for the sensors.
The HC-SR04 sensor is not the most accurate ultrasonic sensor on the market.