#Irregular Terrain Model (ITM) (Longley-Rice) (20 MHz – 20 GHz) (from NTIA)
This is a mirror (July 22, 2015) from [NTIA ITM](http://www.its.bldrdoc.gov/resources/radio-propagation-software/itm/itm.aspx)

#Irregular Terrain Model (ITM) (Longley-Rice) (20 MHz – 20 GHz) (from NTIA)
This is a mirror (July 22, 2015) from [NTIA ITM](http://www.its.bldrdoc.gov/resources/radio-propagation-software/itm/itm.aspx)

#Abstract
The Institute for Telecommunication Sciences (ITS) model of radio propagation for frequencies between 20 MHz and 20 GHz (the Longley-Rice model) (named for Anita Longley & Phil Rice, 1968) is a general purpose model that can be applied to a large variety of engineering problems. The model, which is based on electromagnetic theory and on statistical analyses of both terrain features and radio measurements, predicts the median attenuation of a radio signal as a function of distance and the variability of the signal in time and in space.

#Original NTIA Disclaimer
The ITM software was developed by NTIA. NTIA does not make any warranty of any kind, express, implied or statutory, including, without limitation, the implied warranty of merchantability, fitness for a particular purpose, non-infringement and data accuracy. NTIA does not warrant or make any representations regarding the use of the software or the results thereof, including but not limited to the correctness, accuracy, reliability or usefulness of the software or the results. You can use, copy, modify, and redistribute the NTIA-developed software upon your acceptance of these terms and conditions and upon your express agreement to provide appropriate acknowledgments of NTIA's ownership of and development of the software by keeping this exact text present in any copied or derivative works.

Add abstract and disclaimer from NTIA source
Add abstract and disclaimer from NTIA source