Test Drive: YellowJacket 802.11b Analysis System

By Jim Geier

The Berkeley Varitronics Systems (BVS) YellowJacket is a handheld testing system designed to operate on a Compaq iPAQ so users can analyze 802.11b WLANs. A BVS designed radio unit supplied with this product slides underneath the iPAQ for mobile use. YellowJacket uncovers valuable information, such as access point identification, packet error rate, SSID (service set identifier), multipath, and received signal strength (RSSI).

YellowJacket differentiates itself from competitors by providing a spectrum analyzer display that indicates actual signal levels across the entire 2.4 GHz band. You can watch the signal levels in real-time and capture them in a cumulative mode to better understand the environment over time. This enables you to more accurately characterize sources of RF interference and other WLANs operating nearby.

YellowJacket is a good alternative to purchasing traditional RF spectrum analyzers that are often expensive, bulky, and not geared toward 802.11 networks. At $3,200, BVS puts an adequate RF spectrum analyzer in the hands of the WLAN installer at a tolerable price. Armed with YellowJacket, a WLAN technician can see the RF signals and make better decisions on how to deploy the network.

Another strong point of YellowJacket is the optional Bird’s Eye mapping software. The pricing ($2,500) for this add-on is a bit steep, but it enables you to create facility floor plans and plot WLAN information on-the-fly as you walk through the facility. The software displays access point MAC (medium access control) addresses, RSSI, and SSIDs directly onto the floor plan. It provides a clear depiction of RF coverage, which is extremely helpful when performing RF site surveys and rechecking coverage of an operating WLAN.

YellowJacket is excellent at performing RF analysis, but it lacks extensive 802.11 protocol analysis features. For example, you can’t capture and decode 802.11 frames, a feature important when troubleshooting WLANs. There really is no other tool on the market, however, that currently provides exceptional RF and protocol analysis from a single handheld device. Unfortunately, this leaves you with purchasing two separate devices to fully equip yourself for installing and supporting WLANs.

As with other WLAN analyzers, YellowJacket only interfaces with a single radio NIC–the one that BVS supplies with the product. In fact, the radio NIC is built into the handheld sled that mounts underneath the Compaq iPAQ. There’s no way to interchange the radio with another one. Companies such as BVS have difficulties supporting multiple NICs because of issues related to driver software support. The problem, though, is that you may choose to use a different vendor for access points and radio NICs for your WLAN. As a result, YellowJacket and other analyzers tied to a single radio NIC will provide varying signal strength results as compared to what users of your WLAN will actually experience.

YellowJacket is basically a 2.4 GHz RF spectrum analyzer with a few built-in 802.11 protocol analysis features.

The following describes the primary features of YellowJacket:

  • RF coverage measurements for 2.4 GHz direct sequence WLANs (i.e., 802.11b).
  • Scans all 14 channels and measures/displays access point and station list that includes WEP, RSSI, multipath, packet error rate, SSID, narrow band and total channel power.

  • “Geiger Mode” that provides direction finding for locating individual access points and stations.
  • Network security feature that flags invalid access points.
  • 64 MB of internal RAM memory for storing captured data, with the ability to synchronize data to a PC via IRDA, USB, or serial interface.
  • 256 color backlit display that supplies color-coded signal analysis.
  • Removable battery pack, with interface to a 12-volt source (e.g., car cigarette lighter connection).
    Optional Bird’s Eye mapping software ($2,500 extra).

BVS offers the YellowJacket source code to developers for creating customizable applications. So if you’re developing related applications, YellowJacket can kick start your project into the right direction rather quickly.

Bird’s Eye Features
The optional Bird’s Eye software is a real-time mapping tool that works with YellowJacket. The use of Bird’s Eye is a three-step process: create a floor plan, survey the site, and analyze results. You can easily add rooms, floors, walls, etc., as you walk through the facility. Alternately, you can import existing floor plans and modify them accordingly.

The following are specific Bird’s Eye features:

  • Graphically select measurement points in real-time.
  • Customize area selections based on MAC address, RSSI, SSID, etc.
  • Place markers to identify points sampled during a site survey.
  • Print full color site survey layouts.
  • Plot coverage areas by individual access points or groups.


BVS installs and configures the Compaq iPAQ with the YellowJacket software, so there’s no installation after receiving the product. As part of the YellowJacket product, you’ll find a 3dBi 2.4 GHz antenna, removable battery packs, charger, car power adaptor, and RS-232 cable. After charging and installing the batteries, you’re ready to go. The unit comes in a very rugged carrying case that can withstand extreme abuse, so you don’t need to worry about it being broken when traveling to an installation site.

If you’re interested in seeing the software before making a purchase, you can download free demo software for the PocketPC and personal computers.

Because of the rich RF analysis features of YellowJacket, I highly recommend it for performing RF site surveys, especially for determining the number and location of access points. The optional mapping features will save you considerable time when trying to understand where radio signals are strong enough to classify as acceptable coverage. In order to implement detailed security audits and network troubleshooting, however, you’ll need a tool in addition to YellowJacket in your toolkit.

Jim Geier provides independent consulting services to companies developing and deploying wireless network solutions. He is the author of the book, Wireless LANs (SAMs, 2001), and regularly instructs workshops on wireless LANs.

Model: YellowJacket ($3,200 MSRP)

Pros: Excellent RF spectrum analysis; versatile mapping software (optional).

Cons: Limited protocol analysis ability; single-radio interface.

Reprinted from 80211-planet.com.

Small Business Computing Staff
Small Business Computing Staff
Small Business Computing addresses the technology needs of small businesses, which are defined as businesses with fewer than 500 employees and/or less than $7 million in annual sales.

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