Spectrum Engineering

This report provides the results of measurements that were conducted on a 404.37 MHz wind profiler located in Platteville, Colorado. These measurements included: radiated spectra (both high and low mode), radiated harmonic and subharmonic power measurements, characterization of the antenna frequency response, determination of the radiated antenna gain values near ground level, susceptibility of profiler performance to interference from selected emission waveforms, and the effects on a typical land mobile/amateur operation from wind profiler emissions. In addition, the report presents a detailed wind profiler system description including operations/functions, system hardware, digital signal processing, as well as an

analytical estimation of the interference effects on profiler performance. The information contained within this report can serve as an aid in conducting electromagnetic compatibility (EMC) analysis to determine compatibility between wind profilers and other systems.

The ITS model of radio propagation for frequencies between 20 MHz and 20 GHz (the Longley-Rice model) 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.

 

The model is described in the form used to make "area predictions" for such applications as preliminary estimates for system design, military tactical situations and surveillance, and land-mobile systems. This guide describes the basis of the model, its implementation, and some advantages and limitations of its use. Sample problems are included to demonstrate applications of the model.