Q
Problem solve Get help with specific problems with your technologies, process and projects.

# Is 2.4 GHz affected by rain more than 5.6 GHz?

Is 2.4 GHz affected by rain more than 5.6 GHz? There is a common misconception amongst the wireless community that...

goes a little something like this…

1. Humans use microwaves to cook food.
2. Microwaves emit electro-magnetic radiation in the 2.4 GHz spectrum
3. Microwaves work by exciting the water molecules.
4. The excitation of the water molecules is a result of the transfer of energy from the microwave to the water molecules in the food.
5. Hence the 2.4 GHz electro-magnetic (RF) radiation must be absorbed by the water in order to for the process to work.

Now, if we are to use this proposition as the basis for an analysis of the affect of water on IEEE 802.11b (or any other RF technology that works in the 2.4 Ghz spectrum) then what we'd expect to see would be a lot of useless wireless technology around during periods of rain – but we don't. The above proposition would also mean that if you put a wireless access point into a roof full of people then the signal would basically disappear as it was absorbed by the bags of water walking around the room (which is essentially what we are, large mobile bags of water). However in practice you find some signal degradation but no-where near the magnitude of what you would expect if the peak absorption frequency of water was around the 2.4 GHz mark.

Can you guess what I'm going to tell you next? All those 'wireless experts' that go on about the effect of water on 2.4 GHz technology are wrong. The peak absorption frequency is actually 22.2 GHz, no-where near the 2.4 GHz or 5 GHz spectrums that are currently in use by common WLAN equipment today. For more information I suggest reading the NASA Reference Publication 1108(02) entitled "Propagation effects on Satellite Systems at Frequencies Below 10 GHz."

In answer to your question, the effect of water (or more specifically, rain) is probably actually less on 2.4 GHz equipment than on 5 GHz equipment but in my experience I have found it to be negligible in both cases.

For those of you who are interested here's something very handy to know for the next time some wireless "expert" tells you that "like in a microwave, water absorbs RF" - A microwave works by exploiting the unusually strong dipolar property of water. Although water is electrically neutral, the dipolar state of water allows molecules to behave as if they were composed of small negative and positive charges on either end of a rod. The microwave produces alternative electro-magnetic field, effectively pushing, pulling, rotating and twisting the water molecules and this adding kinetic energy. This addition of the energy to the water molecules comes from the addition of kinetic energy into the molecule itself, not through an increase in the molecules (or any sub-components) excitation state as a result of RF absorbtion.

This was last published in July 2003

## Content

Find more PRO+ content and other member only offers, here.

#### Have a question for an expert?

Get answers from a TechTarget expert on whatever's puzzling you.

You will be able to add details on the next page.

#### Start the conversation

Send me notifications when other members comment.

## SearchSDN

• ### Riverbed SD-WAN gets connections to Amazon, Microsoft clouds

Riverbed SD-WAN now includes support for private connections to Amazon Web Services and Microsoft Azure. Other enhancements ...

• ### SD-WAN vs. MPLS: The quality-of-service comparison

Quality of service is often top of mind for IT leaders when debating SD-WAN vs. MPLS -- especially when it comes to using ...

• ### Enterprises choose managed SD-WAN over DIY SD-WAN deployment

Enterprises prefer purchasing managed SD-WAN services, rather than taking the DIY SD-WAN deployment approach, according to recent...

## SearchEnterpriseWAN

• ### How to calculate network bandwidth requirements

Figuring out how to calculate bandwidth requirements is vital to ensuring your network runs smoothly, and it's best to get the ...

• ### How types of noise in data communication systems affect the network

Learn about the different types of noise in data communication -- including thermal, intermodulation, cross-talk, impulse and ...

• ### The best VPNs for enterprise use

This slideshow highlights the best VPNs used in enterprise wide-area networks (WANs) and offers principles for designing and ...

## SearchUnifiedCommunications

• ### Conference rooms of the future target meeting efficiency

When overhauling your meeting room technology, don't forget the basics, such as high-speed network connectivity and power ...

• ### Evaluate team collaboration tools to increase productivity

Organizations need to consider several factors when buying a team collaboration tool, including deployment options and security ...

• ### Email collaboration evolves in the modern enterprise

Messaging apps are great for team collaboration, but bridging the gap between internal and external communication remains a ...

## SearchMobileComputing

• ### Android Enterprise Recommended touts quick security updates

Google's new program certifies devices that meet minimum hardware requirements, provide regular Android security updates and ...

• ### Make room for AI for mobile in the future

AI is one of the hottest new technologies in mobile. Evaluate the AI market and determine how your organization can take ...

• ### Five steps to effective usability testing for mobile apps

To avoid costly mistakes down the road, conduct usability testing and get a grasp on users' reactions to an app before rolling it...

## SearchDataCenter

• ### IBM Power9 servers seek market inroads to AI, cloud

IBM follows up its first Power9 server with a raft of systems designed to appeal to a wider array of markets -- most notably, AI ...

• ### Evaluate read-intensive and write-intensive SSD use cases

Consider write wear, performance and other factors when choosing between read-intensive, write-intensive and mixed-use ...

• ### Some hyper-converged infrastructure use cases pose pitfalls

Hyper-converged infrastructure adoption is skyrocketing, but that doesn't mean that the technology is the best choice for every ...

## SearchITChannel

• ### SAN storage devices: MSP finds new business in tech upgrade

Evercom, a managed services provider, was able to both upgrade its storage and find a new business opportunity when it purchased ...

• ### Verizon beefs up managed WLAN portfolio with analytics

Verizon is using technology from Mist to anchor a managed SD-WLAN service in an effort to extend its service footprint to ...

• ### Premier BPO gains cloud infrastructure in DinCloud buyout

Premier BPO has purchased DinCloud, a cloud services provider, in a move that acknowledges the increasing importance of scale in ...

Close