Friday, August 26, 2011

How to use Cisco Spectrum Expert (or at least how I use it)

I was chatting with @the_wifi_guy the other day and he asked me if I had any videos on how to use the Cisco Spectrum Expert application. I found an ancient video I recorded back in 2008 when it was called AirMagnet Spectrum Analyzer. I edited out the customer specific information and posted it to YouTube. The video quality was bad and I barely covered the ins and outs of the application but I thought other people might get some use out of it.

Today I finally got around to making a video on how I use the Cisco Spectrum Expert application to find sources of interference, and how to tweak the settings in the application. I had to break the video into two parts since it ran 30 minutes long (!).

Gestalt IT - Wireless Tech Field Day #2 - a call for delegates!

If you've already put your name in to be considered as a delegate for the upcoming Wireless Tech Field Day #2, or you were a delegate at the first Wireless Tech Field Day you don't need to do anything at all.

If you're interested in becoming a delegate for the2nd Wireless Tech Field Day make sure you do put your name in the hat.

I sent out a survey just to my twitter followers hoping to pick up a few more wireless people that maybe I haven't heard from in a while. This goes for anyone reading this too!

If you'd like to attend - let me know who you are, where to find you on the web etc:

Also make sure to fill out the official delegate entry over at

Thanks and I look forward to seeing you in SJC in January 2012!

Saturday, August 20, 2011

AirMagnet Site Survey Pro Comparison to TamoGraph Site Survey

TamoGraph Site Survey

Back in June I received a license for the TamoGraph Site Survey application courtesy of Michael Berg from @TamoSoft. I told them I'd give the application a try and see how it compared to the features I was familiar with in AirMagnet Survey Pro.

I had done a previous compare/contrast with the Ekahau Survey application, but I did not have the TamoGraph software at the time to do a three way comparison.

Several months went by before I had a good indoor survey opportunity to use for the comparison of TamoGraph against AirMagnet. It has then taken me a couple of weeks to find the time to edit the Camtasia video and add a narration audio track to accompany the visual demonstration.

I used the TamoGraph Site Survey application to survey a smaller section of a much larger building  - just large enough to get some good survey data. Using the TamoGraph application was pretty straight forward. The first step was to load the correct driver for my Proxim 8494 USB card for the TamoGraph application. This was as easy as clicking Help > Driver Installation Guide, and then choosing which wireless card I wanted to use with the TamoGraph application.

I did have some problems when trying to use the Intel 6200 AGN card, so I opted to do the comparison by using the same Proxim USB wireless card for both site survey applications.

Starting a new survey is done by clicking 'New Project', defining where you want to store your files, (next), choosing the environment type, choosing measurements in feet or meters and choosing to extrapolate the data beyond the guess range of _X_ feet/meters. Then you choose the scan settings for the 2.4 & 5GHz frequencies (next), then load the floor plan image. The last thing you do before you begin surveying is to scale the drawing to a known distance. For this small demonstration I used a three foot doorway. It is advisable to use a longer known distance than a mere three feet. Using Google Earth can give you the outer dimensions of the building, or you can use a laser tool to measure an wall span within the building.
TamoGraph Site Survey Project Wizard - Environment Type
TamoGraph Site Survey Project Wizard - Scanner Settings

There are several requirements presets that you can choose from in order to determine if the current wireless deployment meets certain 'success metrics'. Each of these requirement presets can be edited and saved as custom presets.

The display options in TamoGraph site survey were very similar to those of AirMagnet. I am including screen captures for each of the applications' drop down menus below.
TamoGraph Visualizations
AirMagnet Menu
AirMagnet Menu (expanded)
AirMagnet Menu (expanded)
There is the ability to change the AP detection and placement on the map. By default TamoGraph will approximate the AP installation location based upon the RSSI detected by the application. This location information is not always accurate since RSSI can fluctuate a bit.

The version of TamoGraph I was using (ver 2.0 Build 44) has a known issue with displaying the manufacturer name of newer Cisco access points. The non-identification problem was caused by the fact that their MACs begin with 88:F0:77, an OUI assigned by IEEE to Cisco very recently. This OUI was missing from the list of OUIs that comes with TamoGraph. The new file will also be included in the next TamoGraph release. Also, the ability to list the AP name will be included in the next release of the TamoGraph Site Survey application.

In order to work around this - I placed the APs exactly where they were located by standing directly under an AP and watching the AP list to see which AP had the strongest signal strength. Then I could place the location of that AP exactly.

Pausing the survey is not possible, instead you simply stop collecting data by clicking the stop button, and then begin collecting data again when you're ready to do so. This is essentially the same as pausing the survey, but just going about it in a different manner.

The survey data looked different from AirMagnet (naturally), but the actual RSSI and SNR values that were detected by each application were the same. There were some things I would have to get used to that the TamoGraph survey accomplished differently. Such as pausing/stopping the survey, having to select the APs you want included in the reporting, and the inaccurate auto placement.  I think if I were to use TamoGraph as my main site survey tool it would suffice for collecting RSSI and SNR data, but I would most likely turn off the auto AP placement.

The display option of  'AP Coverage Areas' looked a little strange to me, and perhaps it would make more sense if the area I was surveying wasn't covered by so many different APs. It seems that the coverage cell for a given AP is indicated as a colored line on the map. I'm not sure if this display would be useful in a densely populated RF environment, but it was an interesting RF display map. It reminded me of some Visios I had to create for a customer once upon a time.

The new features that will be available in TamoGraph Site Survey 2.1 are listed here. According to this information the ability to do predictive planning will be available in a few months.

The YouTube video I uploaded showing the differences between AirMagnet and TamoGraph is here:

The TamoGraph Site Survey application without GPS support is priced at $749 and with GPS support is $999. By comparison, the AirMagnet Site Survey Pro application is priced at $3995 including the Planner module and $1990 without the Planner module.

All in all, I was impressed by the features present in the version of TamoGraph that I worked with. I think that the RSSI/SNR data that was recorded within TamoGraph was just as accurate as that within AirMagnet. For companies on a budget, the TamoGraph application would be a worthy investment.

Friday, August 19, 2011

Yellowjacket b/a/n/g Wi-Fi Analyzer - a review

Recently I had the opportunity to get some hands on time with a Yellowjacket b/a/n/g Wi-Fi Analyzer. I'd heard of the device before, but I'd never come across one in real life. It is also incredibly hard to find out the retail cost of this device. The manufacturer's website only shows the basic information on operating the device. All information requests must be obtained by contacting their sales support team. I have a pending request, but no hard data yet.

This device is an HP iPAQ running Windows Mobile 5.0 encased in a large yellow plastic enclosure which also houses the wireless cards used by the Yellowjacket software. The iPAQ's internal wireless card is disabled and the Yellowjacket wireless card is used for the spectrum analysis. The Yellowjacket softaware is run as an application on the iPAQ, much the same as any other application would be installed/run on an HP iPAQ.

When I was using the Yellowjacket b/a/n/g device, I also had the Cisco Spectrum Expert application running on my Lenovo x201 laptop as a control since I know how the application works under normal circumstances, as well as what the display shows when I enable a wireless security camera as a source of constant interference.

The Yellowjacket b/a/n/g has a series of tabs you can select to show different wireless information. It seems that the tab that would be in use under most circumstances would be the MAC tab. This tab shows the MAC address, SSID, SNR and RSSI of all detected wireless devices and clients.

When I had this screen selected as the main display, and I powered on the wireless security camera - a strange thing happened. The MAC tab display that had previously shown all the detected wireless access points and clients began to show less and less listed devices, until the entire MAC listing was blank.

I navigated through the different filter options for the MAC tab, and found nothing that I could select to show the list of MAC addresses again. When I switched over to the Spectrum tab to see if the wireless security camera showed a disturbance in the spectrum readout. It did, but since the screen is only 640 x 480, the entire 2.4GHz spectrum is shown quite small on the screen. If I were not experienced in using spectrum analysis tools, there would have been no real way for me to visibly discern that there was a source of interference that was critically impacting the 2.4GHz channel 6. The detected spectrum is shown as a green wave form, and there was a visible spike in the waveform, but the color of the spike was still green. To anyone with little spectrum analysis experience, the spike would not have stood out, and green usually means 'good'.

I sent an email on 8/5/2011 to Berkley Varitronics Systems' email address asking about why the MAC display tab began to clear when I powered on the wireless security camera. I have yet to receive a response to my request for additional information to explain the unexpected behavior of the Yellowjacket b/a/n/g Wi-Fi spectrum analyzer.

The device is described as being able to analyze the entire 2.0-4.0 & 4.9-5.9 GHz spectrum, but the 2.4GHz and 5GHz antenna connectors on the device aren't far enough apart to connect the 2.4GHz and 5GHz antennas at the same time. I also didn't see a way in the application to analyze both spectrums concurrently. The inability of the device to detect sources of interference on the 2.4 and 5GHz spectrums at the same time causes the wireless engineer to have to do twice the walking to test the same physical space for both wireless frequencies.

All in all, I was very disappointed in the  Yellowjacket b/a/n/g device. I had hoped that this device would be comparable to the Cisco Spectrum Expert, AirMagnet Spectrum XT and the Metageek Wi-Spy dBx spectrum analyis tools. The simple fact that you cannot quickly switch between scanning the 2.4 and 5GHz spectrums makes the Yellowjacket b/a/n/g a poor choice. The inability of the Yellowjacket b/a/n/g to display and alert the user to the presence of a major source of interference was also very surprising. I hope that I will hear from the Yellowjacket b/a/n/g tech support team and find out why the scan screen ceases to show the previously detected access points and wireless clients once the Yellowjacket b/a/n/g is exposed to a source of non 802.11 wireless interference. Based on my experience using the Yellowjacket b/a/n/g Wi-Fi Analyzer, I could not with good conscience recommend this tool to anyone needing a handheld spectrum analysis tool.

I also made a video recording of the whole process for easier demonstration of how the Yellowjacket b/a/n/g responded under the testing conditions.

Previously posted on YouTube: Cisco Spectrum Expert, AirMagnet Spectrum XT & WiSpy Chanalyzer 4

Previously posted: MetaGeek Chanalyzer Pro - Beta Testing