HeyWhatsThat WISP
Fixed Wireless Analysis

Getting Started videos

Introduction (open at YouTube) The tower list (open at YouTube) Other features (open at YouTube)


Free (as in beer)

Use the URL


and you can save up to five towers in a browser cookie and export up to five towers to a CSV file. (The Save button is under the Towers tab.)

Trial Account

Sign up for a trial account at


The trial account gives you five sessions for $1.

A session lasts twenty minutes. A session doesn't start until you click on the map to request a line-of-sight computation. (So you can work on your tower list, for example, without starting a session.)

You can use the trial sessions with any number of towers.


After you've used your trial sessions,

Mobile Site for Subscribers

Once you have a paid account, try the mobile site at mw.heywt.com


Line of Sight Computation

When you click on a new customer location, we run a computation on the server to determine line of sight to every tower. If there is a clear line of sight, then the tower will be colored green, indicating there's a good chance for a link. If the tower is yellow, then a mast raised above ground to the height listed after the slash will reach a clear line of sight.

But please keep in mind that the profiles and viewsheds are certainly not definitive; e.g. if a customer is a bit outside the viewshed you still may be able to reach them.

If we're getting a lot of traffic, we may stop the demo from automatically requesting the computation, and instead require you to hit the Compute LOS button; the button will be bold in that case.

In the site list on the left there's a indication of LOS quality (+++ ++ + -). This is a measure of the maximum obstruction to the first Fresnel zone (the orange lozenges on the profile graphs).
+++80% or more of the zone is clear (we believe this is the standard RF criterion for a good link, but please let us know if you disagree)
++50% or more of the zone is clear (which means there's a clear line of sight)
 +some of the zone is clear
-zone completely obstructed
The + or - may be colored yellow; if so, the number that follows is the height above ground that you'll get a clear line of sight at the customer location
if the column is blank for all the towers, either the computation hasn't finished (you'll see computing ... at the top of the page), or, as mentioned above, you have to hit the Compute LOS button

We don't know how these actually correspond to signal strength, and we're exploring other propagation models. We're open to suggestions for refining our approach.

Other caveats:

Land Cover Data (trees)

We have imported land cover data for the US (NLCD 2011) and Europe (Corine 2006). Under "Settings" you hit the appropriate radio button, and then

The landcover information is only a visual addition to the profiles; it is not currently taken into account in either the path quality computation (that determines the +++, ++, ... and the color of the towers) or the viewsheds.

In addition to the land cover data, we're looking at US tree canopy data from the same USGS source. The land cover database marks every 30m x 30m block by its type (forest, shrub, developed, ...), while the tree canopy database gives a percentage of tree cover for every block. If you would like to try it out, please get in touch.

Tower Data

Under the Towers tab you'll find an editable table of towers, and you can upload and download CSV format spreadsheet files.

Preparing a CSV

Best to download a sample CSV file, either
English units:

"Name   [v. 1.0]",Latitude,Longitude,"Tower height (ft agl)","Maximum range (miles)","Ground elevation (ft amsl)",Notes,"Viewshed color (RGBA)","Sectors (center/beamwidth)"
"Test tower",44.222857,-69.068648,20,5,777.6,,f1b0b020,

or Metric units:

"Name   [v. 1.0]",Latitude,Longitude,"Tower height (m agl)","Maximum range (km)","Ground elevation (m amsl)",Notes,"Viewshed color (RGBA)","Sectors (center/beamwidth)"
"Test tower",44.222857,-69.068648,6,8,237,,f0b0b020,

and add your own data. Be sure to include the row of headings when you prepare a CSV file to import.

If you want to build spreadsheets with your own data in them as well, leave a blank column (ie. the header row should have a blank column) between the data we require and your data; our import will ignore everything to the right of that blank column.

Things That May Not Be Obvious

Questions From Users