Frequently Asked Questions

Q. Why is TamoGraph much more affordable than the competing site survey products?

A. Surprisingly, this non-technical question is probably the most frequently asked one. TamoGraph is more affordable for a number of reasons. We don't spend money on an impressive office in Silicon Valley. We don't fly first class looking for more venture capital. We've been in the software business for 15 years and we know how to work efficiently, to maintain a high brain-to-fat ratio. We also believe that all WLAN professionals should be able to afford a professional tool to do their job.

Q. Do I need a compatible Wi-Fi card to perform active surveys?

A. No, you can use pretty much any modern Wi-Fi adapter. However, active surveys give you only a small part of the WLAN picture. To get comprehensive information, passive surveys are mandatory. A compatible adapter is required for passive surveys.

Q. My card is not on your list of supported hardware. What are my options?

A. Our hardware compatibility list includes only those cards that we've tested ourselves in our test lab. There are other cards that may be compatible with TamoGraph. The best way to find out if your card is compatible is downloading our Adapter Test Utility and running it on your computer. If a compatible adapter is installed, the utility will display its name. Before running our test utility, make sure that you use the latest driver supplied by your computer or adapter vendor. Visit their Web site to download and install the latest driver version. This is important, because the results of the test depend on the driver that is used. The newer the driver, the better the chances that it will work with TamoGraph. Finally, you may want to buy a compatible card, as they are not terribly expensive these days. Or simply order a boxed version from us; it comes with a compatible USB adapter.

Q. Why is the left panel that is supposed to display the list of access points empty?

A. This might be the case for a number of reasons:

Q. Does TamoGraph support 802.11ac WLANs?

A. Yes, it does.

Q. Do I need an 802.11ac adapter to survey 802.11ac WLANs?

A. This depends on the type of survey. For passive surveys, a supported 802.11n adapter is sufficient, as long as it is a dual-band adapter, i.e., if it can work in the 5 GHz band. Such adapters can capture 802.11ac management frames, which is needed for passive surveys. For active surveys, when your adapter is associated to the WLAN to measure throughput and actual PHY rate, you may want to use an 802.11ac adapter if you need to know the WLAN metrics for 802.11ac clients. However, this is not mandatory, because you may want to estimate throughput for 802.11n clients, which are far more widely used than 802.11ac clients are at the time of this writing. In this case, an 802.11n adapter for active surveys will suffice.

Q. I have a Wi-Spy USB spectrum analyzer. Do I still need a separate Wi-Fi adapter for passive or active surveys?

A. Yes, you do. Wi-Spy can be used for spectrum analysis only. It cannot replace a Wi-Fi adapter because it cannot capture packets or connect to networks.

Q. If I select a small Guess Range, then the predicted coverage at the end of the survey does not cover the whole office area that I am testing. Yet, if I increase the Guess Range, the coverage shadows seem to be bigger and cover the whole office. So I am confused how the results can have any accuracy when the Guess range can easily be manipulated to change the outcome of the coverage visualization.

A. Survey results may have an accuracy close to 100% only if you survey every square centimeter of the floor plan. Of course, this is impossible in practice (and not necessary), so the application has to do some extrapolation work to calculate the results for areas that have not been surveyed but that are near the walkabout path. There is a dependency between the guess range and the environment. If you are in the middle of a stadium field with no obstacles, Wi-Fi signal propagates freely and can be easily predicted dozens of meters around; therefore, you can use a greater guess range. If you are in a crowded office, signal propagation is very complex, so using the guess range that you used on the stadium field would be wrong. TamoGraph recommends a guess range for each environment type; this recommended value should be taken into account when you plan your walkabout paths. For example, if the recommended guess range is 5 meters and you survey the area by walking parallel paths, the distance between the parallel lines should not exceed 5 meters. To sum this up, if you conduct a quality survey by walking the entire area and leaving no “blank spots,” and if your walkabout paths are not far apart, then increasing the guess range would have almost no negative effect. That’s because, in such a scenario, you leave no room for the guesswork.

Q. I noticed that the AP icon location affects the visualizations. When I move the icon, the visualizations change. How can I avoid that?

A. Moving the AP icon may or may not affect visualizations; this depends on the TamoGraph settings. A very detailed explanation of this functionality can be found in the Visualization Settings chapter of this help file; see the How AP icon locations affect signal option description.

Q. Do I need to link the Multi-SSID APs manually to get valid results in the SIR visualization?

A. Usually, TamoGraph tries to group multiple SSIDs together automatically during the survey. However, depending on specific WLAN implementations, it might not be an error-free process. If you noticed that TamoGraph had not detected some SSID groups correctly, it is recommended that you link the SSIDs belonging to the same physical AP manually to get proper SIR results. It is preferable to do manual SSID linking after the entire passive survey is completed.

Q. Does TamoGraph support multi-floor projects?

A. Yes, you can create projects with multiple floors in TamoGraph. If you are doing a predictive survey, simply add new floors in Floor Manager, add floor plans for each floor, define floor height and material, and then align the floors.

Q. Do I need to use the Floor Manager in passive surveys? Does the program take into account the floor materials and floor order in passive surveys?

A. No. The Floor Manager should be used for predictive surveys only. In passive surveys, the application collects actual signal data regardless of the floors and AP locations; in other words, it doesn’t “care” about floors, their order or materials.

Q. I conducted a passive survey in a multi-floor building, and some of the APs were auto-placed on adjacent floors rather than on the floor where they are actually located. How do I correct that?

A. If you know the actual locations of the APs on the their respective floors, then for each floor: (a) manually correct the locations of the APs that are physically located on that floor and (b) drag the icons of all APs that belong to other floors off the floor plan. If you don’t know the actual locations of any APs and wish to view the signal coverage map only, then clear all AP locations; this will make the application use only the actual data, without any extrapolations.

Q. I have one physical AP that I want to move around to simulate multiple APs before deploying my WLAN. Can TamoGraph treat this single AP as multiple APs so that I can estimate the characteristics of the future WLAN?

A. Yes, this widely used method is called “AP-on-a-stick”. TamoGraph provides the functionality necessary to handle such scenarios. Please see Splitting an AP into Multiple Unique APs for detailed instructions.

Q. It appears that there are very few virtual AP templates and all of them are for generic APs. How do I create a virtual AP that simulates a specific model by a major Wi-Fi equipment vendor?

A. Virtual APs can be constructed like Legos. For example, if you want to simulate a Cisco Aironet 2700 series AP, you should begin with the Generic dual 802.11ac template. Place the AP on the floor map, double-click on it, configure its properties to match the properties of the physical AP you plan to deploy (e.g., channel width or output power), and then select the antenna type, which in your case should be Cisco Aironet 2700 series 4 dBi. Be sure to do this for both radios of this dual-band AP. In other words, you use Lego bricks to build a model that matches the actual AP. You can then save this configuration as a new template and use it in your projects. Why don’t we provide you with a ready-to-use model? Because we cannot know how you plan to configure your physical Cisco Aironet 2700 series APs. For example, we cannot know whether you plan to use 20 or 40 MHz channels in your APs. This is why you have the utmost flexibility in creating your own template.

Q. Is there a way to tell the software to ignore all APs except the one with which I am are surveying?  I want to collect data for our survey AP only and generate a report for this AP only.

A. You can have visualizations for any set of AP, even a single AP. There are two buttons on the toolbar that switch between the “All APs” and “Selected APs” modes, so you can press the latter and select only one AP on the left pane. Please note that in case of the Signal-to-Interference Ratio visualization, the signal of the selected AP is analyzed against all APs in the projects.

Q. Can I use multiple adapters with TamoGraph to make the scanning process faster?

A. Yes, TamoGraph can capture data from multiple channels simultaneously if you use multiple compatible USB adapters. This shortens the time needed to collect data from the channels being scanned as you move along the survey path, and, therefore, improves the data quality. For example, with the default 250 ms per channel interval, it takes five seconds to sweep through 20 channels if you use only one adapter. If you use three adapters, the same amount of data will be collected in less than two seconds. The following 802.11n USB adapters can be used for multi-channel capturing: D-Link DWA-160 v.A1, v.A2, v.B2, and v.C1, Edimax EW-7733UnD, Linksys AE3000, NETGEAR WN111 v2, NETGEAR WNDA3100 v1, Proxim ORiNOCO 8494, SMC Networks SMCWUSB-N2, Sony UWA-BR100, TP-Link TL-WDN3200, TP-Link TL-WN721N, TP-Link TL- WN722N, TP-Link TL-WN821N v1, v2, and v3, TP-Link TL-WN822N v1 and v2, Ubiquiti SR71-USB, and CACE Technologies AirPcap Ex or NX. The following 802.11ac USB adapters can be used for multi-channel capturing: Belkin F9L1109 v1, D-Link DWA-180 rev A1, D-Link DWA-182 rev C1, Edimax EW-7822UAC, EnGenius EUB1200AC, Linksys WUSB6300, NETGEAR A6210, Proxim ORiNOCO 9100, TP-LINK Archer T4U, TRENDnet TEW-805UB, and ZyXEL AC240. Note that different types of adapters cannot be mixed; all of the adapters should be of the same model. You should also install the same driver for all of the adapters.

Q. Some of the channels in the scanner options window are not listed. Is this normal? What if I want to monitor these channels? Is this normal? What if I want to monitor these channels?

A. The answer depends on the adapter type:

Q. Why is the UDP downstream throughput value always zero?

A. This is a firewall issue. This means that the UDP data being sent from the server cannot reach the client. When performing UDP testing, the client sends upstream UDP traffic to the server from a random UDP port to the server port (27100 by default.) The return downstream traffic goes from port 27101 to the client source port. Use this information to configure your firewall.

Q. Why do I see very high (over 50%) UDP downstream loss?

A. This question is answered in the UDP Upstream and Downstream Loss chapter.