spectrum analysis

CTS 109: Ekahau Sidekick, Spectrum Analysis, and Finnish Rap

Special guests, Samuel Clements and George Stefanick join the show to discuss the Ekahau Sidekick with Rowell Dionicio and Jussi Kiviniemi.

CTS 109: Ekahau Sidekick, Spectrum Analysis, & Finnish Rap

Ekahau Sidekick

Wireless site surveys have been performed with USB adapters for a long time. Many have had grueling battles with getting these USB adapters working, we’ve had them fail, and have seen varying inconsistencies between adapters. Or if you’re me, I nick my adapters all the time.

Recently, Ekahau came out with a game changer. It replaces all your USB adapters into a shoulder strapped, supercharged, all-in-one measuring device. As said on the product’s website, the Sidekick dramatically streamlines the site survey process by replacing and outperforming the previously-used USB hubs providing greater reliability, accuracy and convenience.

That’s our discussion in this episode regarding the Sidekick. How does it stand out in the field in terms of performance, reliability, and accuracy. The added benefit here is convenience.

In this episode, I start things off by asking why the development and release of the Ekahau Sidekick. You’ll get the response directly from Ekahau but additionally, we hear from two customers – Samuel Clements and George Stefanick.

Some of the reasons why they prefer to use the Ekahau Sidekick:

  • Reliability
  • Consistency
  • Performance
  • Receive sensitivity dial
  • Ease of use

Ekahau decided to build the Sidekick from scratch to produce a device capable performing excellent spectrum analysis and Wi-Fi gathering capabilities. Listen to the episode to hear more of our discussion.

One special treat, Jussi shows us what Wi-Fi sounds like.. Yes you read that right.. what Wi-Fi sounds like. You hear it in this episode.

And finally, Finnish Rap

Links & Resources

CTS 066: Spectrum Analysis with Joel Crane

Joel Crane is our special guest on CTS and he has a lot of knowledge bombs on spectrum analysis. Be sure to listen to this episode.

Interference. The invisible killer of your spectrum. It creates a terrible user experience and your network is to blame for it. Spectrum analysis is how you’re going to identify what is kicking your Wi-Fi to the side.

I’ve used this process to find issues the users are experiencing. Often times the fault is placed on the WLAN but it is either done unintentionally or on purpose. You will usually find out that there is a misbehaving device or a consumer level hardware causing issues with the WLAN.

In this episode, Rowell and François ask Joel Crane questions about what spectrum analysis is and why is it useful.

Spectrum Analysis with Joel Crane

  • Detecting, identifying, and locating non-WiFi interference
  • Gauging co-channel/adjacent interference
  • Who uses it
  • Cool stuff to know about
  • The troubleshooting process
  • Duty cycle vs. utilization
  • Real-time FFT vs Swept-Tuned

Resources Mentioned

Sample Spectrum Captures

This Week In Wireless

CTS 052: How To Validate Wi-Fi Infrastructure

In this episode, I talk with Francois Verges of Semfio Networks about how to validate the Wi-Fi infrastructure.

Validating a Wi-Fi network involves many steps. This is not isolated to a new deployment but also to an existing Wi-Fi network. Francois and I talk about what to validate, look out for, and what resources are available to assist on the job.

Validate Physical Installation

  • Walk through the facility
  • Validate
    • AP installation
    • Antenna orientation
    • With the customer
    • Telco room location

Post Deployment Survey

  • Use your survey laptop and try to use a business critical business device as well (VoIP phone, handheld scanner…)
  • Connect to the infrastructure. Use the most business critical SSID.
  • Use Ping or iPerf to test connection, roaming, throughput.
  • Things to look at while performing the exit survey:
    • What band is the survey laptop using?
    • What band is the client device using?
    • Am I roaming as expected
    • RSSI of both your laptop survey and the client device
    • If you use ESS, you can also connect 1 or 2 dBx antenna to perform a parallel spectrum analysis. (Detect noise and major interferences)

Things to look at after the survey:

  • Coverage
  • Channel distribution / Channel re-use
    • See if some Tx Power need to be adjusted
    • See if some radios need to be disabled (2.4GHz)
    • See if more 5GHz channels are needed
    • Making sure that all the configured channels are being used.

Spectrum Analysis

  • Study both bands: 2.4GHz is usually where you will find the most external interferences
  • Stay still at one location. If you see something unusual, move around to pin point the exact location of the source. (might not be easy). – Plan for a little extra time.

Packet Capture

  • Get a better idea of the RF environment (using Eye P.A.). Thing to look at:
    • Retry rates
    • Channel airtime utilization
    • Data rates
    • How the neighbours can be affecting some channels
  • Being able to see more advanced radio configurations such as:
    • data rates
    • AP capabilities
    • Client capabilities (Big one)
    • Being to spot unusual behaviours
    • Being able to troubleshoot some client issues

Analyze Client Behavior and Configuration

  • Make sure all the client devices of the same model have the same Wi-Fi NIC drivers
  • Make sure all the client devices of the same model have the same Wi-Fi configurations
  • Make sure they manage to connect to the Wi-Fi network (Check delays, does it take a long time to connect?)

Perform Functional Validation Testing

  • Grab a client device, roam around the facility (especially where the device will be used)
  • Validate how the client roams
  • Validate on what band the client connect to
  • Try to ping the application server and see if you lose any pings (make sure it does not affect production)
  • Validate voice quality if it’s VoIP
  • Validate throughput if the requirements need it (try to use the same applications as the one what will be used on the Wi-Fi)

Links and Resources

CTS 039: When and How To Use Spectrum Analysis

Interference

Thank you for joining us on another great episode. The topic of episode 39 is when and how to use spectrum analysis.

Spectrum analysis is a crucial part of wireless site surveys and for troubleshooting. When performing spectrum analysis as part of a wireless site survey, an engineer can determine which areas contain sources of interference that can greatly degrade the performance of a wireless network.

Some interference is non-802.11 traffic. Wireless NICs within devices cannot demodulate these signals. If a transmission occurs with interference present, the frames are corrupted.

It’s important to know the different kinds of interferences that can exist.

  • Sporadic (happens only at specific times). An example is bluetooth
  • Constant (the interference is there all the time). Example: Wireless Video Camera
    — Both can be disruptive to the Wi-Fi if the duty cycle is high
    — There is also the width of the interference to validate.
  • Do not forget to watch out for interference from other Wi-Fi networks (even yours…)
  • Duty cycle
  • ACI

Links and Resources