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We do not provide simulated or predictive RF modeling. We strongly believe that you need to actually measure radio waves in the field to get a realistic picture of your wireless coverage. We recommend using a temporary access point during a pre-deployment site survey. VisiWave makes this quick and easy.

To begin, place a temporary AP (it doesn't have to be connected to the network, just powered up), collect survey samples, and save the results in a survey file. Then move the temporary AP, collect more samples, and save the results in a different survey file. Repeat this process until the entire area is covered. When creating a report, you can then merge the survey files together into one large survey file using the Merge Survey Files menu item found in the Reporting application. By selecting the "Force APs to be unique" option, your one temporary AP will look like many individual APs when you create coverage graphs. VisiWave treats each AP location as a unique AP in the reporting results. Look up "Merge Survey Files" in the supplied User Guide for more information.

Using this method, you can view each AP's coverage and get an overall view of your wireless network. Also, taking actual measurements allows you to view any overlapping coverage provided by external access points. This will show you what areas contend with neighboring access points and what channels those APs are using.

To start with, here are some discussions about how VisiWave creates it's heat maps.

VisiWave interpolates what it thinks is the coverage in areas where you didn't collect data. This is just a guess and it is best to actually collect data there, but VisiWave does a decent job estimating coverage in these areas based on what it knows.

When creating the coverage graphs, VisiWave needs to divide the survey area up into cells. It then takes the data points you collected and assigns coverage values to each cell.

If VisiWave could depend on you to collect data in a regular pattern throughout the entire survey area, it wouldn't need to form these cells. But that is an unrealistic expectation so the cells are necessary and effective for real-world data collection.

So how big are the cells? Assume your survey area is roughly square. Then each cell takes up about 1% of the area. So an area 100m by 100m would have a cell 1m by 1m. If your survey area is twice as wide as it is deep, then the cell size would be about 1% of the width and 2% of the depth. For example, an area 200m wide by 100m deep would have a cell size of 2m wide by 2m deep.

So as a general rule, you should collect a data point about every 1% to 2% of the total width/height of your space. So in a space that's 500m by 500m you should take a reading about every five to ten meters in each direction. More frequently is fine and may produce more detailed maps. As stated above, you usually aren't able to collect data in a perfect grid so the software fills in where you don't collect data.

It should also be pointed out that the level of detail you set for the graph comes into play. The above discussion assumes you have chosen the highest level of detail. If you lower the detail level, then you also lower the number of cells (making each cell larger). In general, setting the detail level to half will roughly double the size of each cell which means you can collect data that is even further apart.

To completely simplify the above, if you are surveying a decent sized building, you want to collect data at least every 5 to 10 feet (2 to 3 meters). If you are surveying a downtown area, you might want to collect data more like every 25 to 50 feet (10 to 20 meters)--or better.

Google Earth integration is very easy as long as you know how to set the latitude/longitude position of your survey area map.


The first place to start when trying to use Google Earth with VisiWave is our online tutorials. They cover all the steps necessary to collect data and create a Google Earth export file. Click on the Tutorials link on our homepage. Start by viewing Demo 3: Collecting Survey Data. Then view the two tutorials on collecting survey data and viewing it using Google Earth. The tutorial Demo 2a: Using Google Earth with VisiWave shows how to use Google Earth with a VisiWave coverage graph.

Some other tips:

• Make sure that when you collect data, the top of your survey area map points north.


• Make sure your Scale is set accurately (otherwise the overlaid graphs won't line up with the Earth's surface).


• If you aren't using a GPS, you'll still need to set the latitude/longitude of your map. You can use Google Earth to get the lat/long position of a place on your map and then enter that in VisiWave (see the tutorial).


• If you are doing a large survey and then try to export everything to Google Earth, the resulting KML file might be so large that it is cumbersome to use. On large surveys, you should split the export up into smaller sections: possibly including a subset of access points (using the "APs to Include" parameter), including the spectrum data in a separate file, or including just data combined by SSID (instead of including data on each individual access point).


• When viewing the export window, press F1 or click on Help to view detailed information on each parameter.

The first thing to check is that you installed the Serial-to-USB driver that comes on the small CD along with the USB-to-Serial conversion cable. Nothing will work without first installing the appropriate drivers. Windows should prompt you for this CD when you first connect the converter cable.

Next, make sure you have selected the correct COM port for your serial device. Under VisiWave, select the Option menu item under the File menu. Select the correct COM port next to "Nav Unit Serial Port".

To find out which COM port is the correct one, go to Windows' Control Panel. Double click on System. Click on the Hardware tab. Then click on the Device Manager button. Scroll down until you see "Ports (COM & LPT)". Click the plus next to this item. You should see an entry that starts "Prolific USB-to-Serial Bridge" followed by a COM port. That is the correct port number. If you don't see this entry, then the driver was probably not installed.

The navigation unit should now be usable by VisiWave. If you continue to have problems, as always, just send an email to support and we would be more than happy to help you.

Should you select "All" or "Only Strongest in each Cell" for the Data Points Included option on a 2D contour graph? And does this have anything to do with what you select under the "APs to Include" parameter?

When creating a 2D Contour graph, the survey area is split up into many small cells. Each cell potentially contains several different collected data points. Using this option, you can either use all data points found in the cell to determine the overall value of the cell, or you can specify that you only want the data points that come from the access point with the strongest signal to determine the overall cell value. Selecting "Only Strongest AP in each Cell" tells the product to sort through all the data points found in the cell and only examine the points that come from the access point with the strongest average signal level. The other data points are simply ignored.

Regardless of which setting you select, only the APs you selected in the APs to Include parameter are examined. Typically you would want to select "Only Strongest AP in each Cell". This simulates what coverage a laptop would see. The laptop would usually look at the AP with the strongest signal at its current location and ignore the others.

If you are just starting out with VisiWave Site Survey, the best place to look for help is to view one of our online tutorials. Each lasts just a few minutes, but they show you the most important features of the product.

You probably want to start with the "Collecting Survey Data" tutorial. It goes over loading a survey map, setting the scale, collecting survey data using two common methods, and exporting graph data to Google Earth.

You will also want to look through our Quick Start Guide. This short guide goes over collecting survey data and creating reports.

You can also always read the manual. It is installed as part of the product (even with the eval version). Just go to the Start menu, click on All Programs and then on VisiWave Site Survey. You'll see a link labeled User's Guide. This brings up the guide in your PDF viewer.

VisiWave also has a lot of help built into the application. Just press F1 or select help from the Help menu. Most every feature, button, and field in the program is explained in the built-in help system.

Of course, you can always email us for help as well. We do our best to give you thorough and timely answers to all support emails.