2012 Archive

What losses are included in the “XPL” (excess path)

All path loss that is not Free Space loss (diffraction, fresnel zone, reflections, clutter):

Percentage of Location variability margin (propagation parameters dialog)
Percentage of Time variability margin (propagation parameters dialog)
Margin (in dB) (propagation parameters dialog)
Atmospheric Absorption (>20GHz) (propagation parameters dialog)
Reflection Loss

Reflection loss can cause a large amount of variability between study locations. This is because a small … [ Read More ]

RF Simulation Accuracy Considerations

Simulation accuracy of any RF modeling program is dependent on many factors the most important being:

Accuracy and resolution of the terrain, building, and clutter data
Propagation model used
Choice of time/location/margin values
Physical characteristics of the study area (plains, mountains, urban, etc)
Experience and skill of person using the tool

With a good physical propagation model (such as Anderson 2D) … [ Read More ]

Calculating global clutter margin values

When a clutter databases is not available the following formulas can be used to calculate a “global” clutter value that is entered in the “Margin” in the Propagation Models dialog:

Urban = 16.5 + 15 log10(? /100) – 0.12d dB
Suburban = Urban -12.0 dB
Dense foliage = 65.0 (0.244 log10(?) – 0.442) dB
Sparse foliage = Dense foliage … [ Read More ]

Using EDX programs under Remote Desktop or Terminal Services

EDX software applications behave the same way under “Terminal Services” on a Windows 2003 machine and “Remote Console” on Windows 7/Vista machines. Microsoft Terminal Services allows multiple people to use the resources of a Windows 2003 server. Each Terminal Services user has their own “session” which is essentially a Virtual Machine on the server.

In order … [ Read More ]

Updating Bing Map Key

The release of EDX software v7.4/10.4 and later includes a map layer that queries and uses results from Microsoft’s BING map server, allowing for display of those images in EDX Software. Access to this feature is controlled by a license key that BING provides to us. This key expires twice a year, once on June … [ Read More ]

HASP key drivers – command line reinstall

Sometimes the HASP hardware key driver will not get properly installed and the normal HASP GUI installation program cannot resolve the problem. In this case, a more flexible driver installation must be used from the computer’s command line or “Run” window.
Go to http://www.safenet-inc.com/. Follow the “Support and Downloads” tab to Technical Support. From the … [ Read More ]

Computer system requirements for EDX Software

DX software products are computationally intensive programs with large file i/o requirements, and for this reason, it’s not just a simple matter of getting a faster processor or larger hard disk to increase performance. It’s further complicated by the choice of 32-bit vs 64-bit operating systems. This document will guide you to setting up your … [ Read More ]

EDX antenna pattern file format

Here is a description of our pattern file format. The .PAT folder inside the program on the hard drive contains examples. Instructions are alos available in Appendix I of the EDX reference manual.

This file is a tabulation of azimuths and relative field or dB values that describe a directional antenna pattern. Both horizontal and vertical … [ Read More ]

Using Computamaps terrain and clutter data

The free terrain and clutter data found on the Computamaps.com website is compatible with EDX software. Here are a few suggestions on using the data:

Terrain Elevation Data (dtm folder)

Open the “projection” file in a text editor and make sure the first line is “GRS-1980” not “GRS-80”.
In the EDX Databases/Terrain dialog set the database type to … [ Read More ]

Simulating the Lee propagation model

The Lee model is a simple power law model that uses only the average elevation of the terrain along each radial to adjust the path loss along the radial. It assumes flat ground and does not include any terrain or building obstructions.

The model can be expressed as:
Loss(dB) = (n * 10log(R)) – 20log(Hb) – … [ Read More ]