WIRELESS INFRASTRUCTURE

  • 10/20/2015
    7:00 AM
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Wireless Troubleshooting: Measuring WiFi Signal Strength

Understanding how well your WiFi access points hear your clients can help with tricky WiFi problems.

I am a big fan of teaching methodology. I always ask people who attend my presentations not to focus on my results, but rather to understand how I do things so they can reproduce my test.

In this video, I discuss the merits of measuring WiFi signal strength by understanding how well your WiFi access points hear your clients. I chose a popular Samsung Galaxy S2 smartphone and recorded the receive signal strength from the access point’s perspective.

When you conduct this type of test, you should be aware that many WiFi devices will change the radio behavior depending on power and if it's transmitting any data. To ensure consistency, I simply "pinged" the phone’s IP address every 10 millisecond using hrping.

As I explain in the video, I’m not expecting you to do this for every device, in every location in every orientation, but think it's important to understand this behavior for those tricky WiFi issues.

I actually used this methodology when troubleshooting a problem in a warehouse with WiFi terminals mounted in forklifts that were dropping their connections. In the end, I found two very important details:

  • The signal strength was marginal at best since the survey was completed using highly sensitive directional antennas and the terminals had less-sensitive omnidirectional antennas.
  • There was an area of the warehouse with a lot of metal shelving that, in combination with the forklift orientation, caused the RF signal to drop and the connection to drop.

Good luck with your wireless troubleshooting! 


Comments

wireless troubleshooting

Thanks for another great video Tony. I'm curious, how did you resolve the problem in the warehouse?

Re: wireless troubleshooting

i got lucky in a sense with that one.

I ended up repositioning many of the AP's to provide better coverage for the forklifts. Some of the AP's were installed in areas where there was no requirement for coverage.

 

Re: wireless troubleshooting

Extremely interesting, while working at the edge of the wireless network, I have always considered solutions in which the AP could be brought 10% closer by distance. Definitely, the next time I will try to change the device orientation to gain a 10% better signal strength. Thank you.

Re: wireless troubleshooting

thanks for taking the time to provide your feedback and glad it helped you pickup something new.

Re: wireless troubleshooting

Very educative! Thanks.

Re: wireless troubleshooting

You're welcom.  

Thanks for the comment.