The Longley Rice Website
The well known algorithm for terrestial propagation analysis.
Here we are going look at who Longley and Rice were. Explain the propagation analysis algorithm and lead on to a dedicated terrestial propagation analysis website using the Longley Rice analysis.
Who
In reality Longley and Rice are two different people.
Anita Longley, Phil Rice, and their colleagues at the Central Radio Propagation Laboratory (CRPL) (now the Institute for Telecommunication Sciences (ITS)). In the 60's they developed an empirical model (based on electromagnetic theory) with measured data (terrain features and radio measurements) to create what is now known as the LongleyRice Irregular Terrain Model (ITM).
Anita Longley was born in the province of Saskatchewan, Canada 1908 and died in 1986. She received her BA in Physics from McMaster University and MS in Physiological Chemistry from the University of Minnesota. After serving as a research assistant and teaching at the high school and university, she joined the National Bureau of Standards (NBS) CRPL in Boulder, Colorado, in 1955.
Philip Rice was born Washing DC in 1922 and died 1997. He attended Lawrence College, Appleton, Wis., in 1941, and received the B.S. degree from the Principia College, Elsah, Ill., in 1948. Phil Rice specialized in mathematical modeling, tropospheric propagation, satellite and space communication. Since 1949 he was with CRPL Colorado.
What
Using the corrected initial LongleyRice Fortran program the code has been translated to an interactive C# ASP Net version which has been made available on a Speciality Radiospurs web site.
This site offers the possibility of point to point link analysis and area broadcast analysis. The ground terrain profile is derived from the NASA SRTm v3 data with, in general, 90m cell spacing. The maps are from the OSM venture. All of the civilised world is most definitely covered and some of the dubious quality areas.
In the broadcast area mode a variety of antenna types are offered so that coverage with a specific lobe pattern can be obtained. To design your antenna:
How
Quite a large number of parameters are required for an analysis.
So we go through an example of each type, by clicking on one of the links given below.