Application Note - 900 MHz vs 2.4 GHz in XStream radio modems.

To determine whether you should use 900 MHz or 2.4 GHz RFd2d technology for your products you need to answer the following:

  • What is the maximum range your product needs to communicate?
  • Will your product be deployed outside North America or Australia?

What is the maximum range your product needs to communicate?

The major difference between 900 MHz and 2.4 GHz wireless OEM modules is range. While Digi's 9XStream (900 MHz) offers much greater range than the 24XStream (2.4 GHz), the 24XStream is more accepted internationally. The following table lists specific differences between the 9XStream and 24XStream.

Feature 9XStream (900 MHz) 24XStream (2.4 GHz)
Pager & cell rejection 70 dB Pagers and cell phones seldom interfere with this band
Transmit power 20 dBm 17 dBm
Receive sensitivity -110 dBm -105 dBm
Range
(9600-baud module, line-of-sight)
Indoor: 1500'
Outdoor: 7 miles with dipole antenna, over 20 miles with gain antenna
Indoor: 600'
Outdoor: 3 miles with dipole antenna, over 10 miles with gain antenna
Path loss
(for more information, see the section "Comparing Wave Propagation of 2.4 GHz and 900 MHz Frequencies")
Because the 24XStream operates at 2.4 GHz, it has +8.519 dB more path loss than the 9XStream which operates at 900 MHz
Unlicensed operation North America and Australia Worldwide
TX current consumption
(when not in power-down mode)
170 mA 180 mA
RX current consumption
(when not in power-down mode)
70 mA 90 mA

Simply put, if your range requirements are beyond 375 feet indoors, or beyond 1.4 miles outdoors, we recommend the 9XStream or 9XTend over any other 2.4 GHz product. The 9XStream and 9XTend prove to be a longer range, lower power, and lower cost solution than most 2.4 GHz products.

Will your product be deployed outside North America or Australia?

Another difference between 900 MHz and 2.4 GHz solutions is that the 900 MHz radio frequency band is for unlicensed use only in North America and Australia. Worldwide (including North America and Australia), 2.4 GHz is an unlicensed radio frequency band.

If your product will be deployed worldwide, we recommend the 24XStream 2.4 GHz wireless products. The 24XStream offers longer range, lower power, and advanced networking capabilities not offered by other 2.4 GHz solutions.

Conclusion

9XStream & 9XTend 900 MHz products are best used in long range, low power applications deployed in North America and a few other locations. 24XStream 2.4 GHz products are best used in applications deployed worldwide.

Last updated: Aug 08, 2017

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