user20243: I'm using two nRF24L01 to communicate with each other. I did the right setup and they worked fine, however I wanted to change the air data rate to a lower value, for more stability, as the datasheet says.
How can I setup the configuration for this?
After a small research I knew that you can change this using RF_DR 
to change the value of the transmission, but I didn't really know how I could exactly write the correct code for this. 
Another question: does this effect the range of the module? Or does it only affect the stability? And if not, then which code can I use to extend the range of these two modules ?

user2881: Increasing stability will increase the (usable) range. At least a bit. You could try decreasing the packet size, to make it even more reliable. There is no way to increase the output-power (only decrease). 
You could try different channels, and see which one gives you the best range in your application. 
After that you have to get NRF24 modules, with external antennas and amplifiers.

user69586: According the nRF datasheet if you decrease the data rate it will definitely affect your range.
A lower data rate will increase your stability due to which the nRF can detect weaker signals (-102 dB at 250Kbps) due to this you can significantly increase the range (up to 1km theoretically).
Also if you need to increase your range further you can attach an antenna with a higher gain than what you already have.
No other software changes will affect the range other than reducing the transmission speed.

20243: <p>I'm using two <a href="http://www.nordicsemi.com/eng/Products/2.4GHz-RF/nRF24L01" rel="nofollow noreferrer">nRF24L01</a> to communicate with each other. I did the right setup and they worked fine, however I wanted to change the air data rate to a lower value, for more stability, as the <a href="http://www.nordicsemi.com/eng/content/download/2730/34105/file/nRF24L01_Product_Specification_v2_0.pdf" rel="nofollow noreferrer">datasheet</a> says.</p>

<p>How can I setup the configuration for this?</p>

<p>After a small research I knew that you can change this using <code>RF_DR</code> 
to change the value of the transmission, but I didn't really know how I could exactly write the correct code for this. </p>

<p>Another question: does this effect the range of the module? Or does it only affect the stability? And if not, then which code can I use to extend the range of these two modules ?</p>
 2881: <p>Increasing stability will increase the (usable) range. At least a bit. You could try decreasing the packet size, to make it even more reliable. There is no way to increase the output-power (only decrease). </p>

<p>You could try different channels, and see which one gives you the best range in your application. </p>

<p>After that you have to get NRF24 modules, with external antennas and amplifiers.</p>
 69586: <p>According the nRF datasheet if you decrease the data rate it will definitely affect your range.</p>
<p>A lower data rate will increase your stability due to which the nRF can detect weaker signals (-102 dB at 250Kbps) due to this you can significantly increase the range (up to 1km theoretically).</p>
<p>Also if you need to increase your range further you can attach an antenna with a higher gain than what you already have.</p>
<p>No other software changes will affect the range other than reducing the transmission speed.</p>
