SRF10 range distance setting

Hi everyone,
I'm working on a project of an indoor quadcopter. And i want to put some srf10 on it to detect walls. I have already take a look to https://www.arduino.cc/en/Tutorial/SFRRangerReader and http://www.robot-electronics.co.uk/htm/arduino_examples.htm#SRF02,%20SRF08,%20SRF10,%20SRF235 but i don't understand how to set up the range. In fact i had already connected the SRF to my arduino Uno and getting some distance from 0 to 50 cm but i need something like 0 to 1500 or 2000. If i had corretly read the datasheet the SFR10 can provide distance up to 6m, but i don't get how to achive that ?

Thanks

To detect anything at six metres, it would have to be pretty big, hard, flat and square on to the sensor.
What sort of things are you trying to detect?

I'm trying to detect walls. But i need only a range of 1 to 2 meters, not 6.

You still need to be pretty square-on to the walls.

Have you read the manufacturer's technical specifications?

They also have a FAQ page.

Would your prop-wash, perhaps, be within that 0-50cm range??

Try top mounting the sensor(s) and angle up 15 to 30 degrees. Calculate (or measure) the range indicated when the quad is at the edge of your safe distance to the wall, use that distance as the cutoff point in your avoidance routine. (you might think about distance per time traveled in determining when to cutoff).