I was wondering why they have not mentioned the transmission distance in the datasheet?. This was the same case for most of the devices i searched.

All of the chip manufacturers mentioned the RF range of their wireless device in terms of **Transmit power** and **Receiver sensitivity**.

To calculate the RF range you need to understand the term Link budget.

The Transmit power and receiver sensitivity are specified in **dBm**.

**Definitions**

dBm – relative to 1 mW

10mW = 10dBm, 0dBm = 1mW

-110dBm = 1E-11mW = 0.00001nW

**Rules of thumb :**

**Double the power = 3 dB increase****Half the power = 3 dB decrease**-
**120 dB link budget at 433 MHz gives approximately****2000 meters (Chipcon rule of thumb)** **6 dB improvement ~ twice the distance****Double the frequency ~ half the range****433 MHz has longer range than 868 MHz**

Using the above rules we can calculate approximate range of RF devices ,

**For example,**

If we want to find the range of 2.4GHz RF devices then using the above information,

**120dB **link budget @ **433 MHz **gives **2000 **meters

**120dB **link budget @ **866 MHz **gives **1000 **meters (*double the frequency ~ half the range using rules above*)

**120dB **link budget @ **1732 MHz **gives **500 **meters

**120dB **link budget @ **3464 MHz **gives **250 **meters

So, **120dB **link budget @ **2400 MHz** gives approximately **360 meters **range

Look at the specs below from TI CC24xx wireless device which show that the range is doubled with a increase in link budget by **6 dBm**