UHF Radio Wave Attenuation Factor Database

2007 ◽  
Author(s):  
S. I. Khomenko ◽  
V. L. Kostina ◽  
I. M. Mytsenko ◽  
A. N. Roenko
Keyword(s):  
Radio Wave ◽  
Wave Attenuation ◽  
Attenuation Factor

scholarly journals Event couple spectral ratio Q method for earthquake clusters: application to North-West Bohemia

2018 ◽  
Author(s):  
Marius Kriegerowski ◽  
Simone Cesca ◽  
Matthias Ohrnberger ◽  
Torsten Dahm ◽  
Frank Krüger
Keyword(s):  
Wave Attenuation ◽  
Attenuation Factor ◽  
Source Region ◽  
Spectral Ratio ◽  
Ratio Method ◽  
Earthquake Swarms ◽  
North West ◽  
High Attenuation ◽  
West Bohemia ◽  
Spectral Ratio Method

Abstract. We develop an amplitude spectral ratio method for event couples from clustered earthquakes to estimate seismic wave attenuation (Q−1) in the source volume. The method allows to study attenuation within the source region of earthquake swarms or aftershocks at depth, independent of wave path and attenuation between source region and surface station. We exploit the high frequency slope of phase spectra using multitaper spectral estimates. The method is tested using simulated full wavefield seismograms affected by recorded noise and finite source rupture. The synthetic tests verify the approach and show that solutions are independent of focal mechanisms, but also show that seismic noise may broaden the scatter of results. We apply the event couple spectral ratio method to North-West Bohemia, Czech Republic, a region characterized by the persistent occurrence of earthquake swarms in a confined source region at mid-crustal depth. Our method indicates a strong anomaly of high attenuation in the source region of the swarm with an averaged attenuation factor of Qp 

scholarly journals Empirical Model of Radio Wave Propagation in the Presence of Vegetation inside Greenhouses Using Regularized Regressions

Sensors ◽  
2020 ◽  
Vol 20 (22) ◽  
pp. 6621
Author(s):  
Dora Cama-Pinto ◽  
Miguel Damas ◽  
Juan Antonio Holgado-Terriza ◽  
Francisco Manuel Arrabal-Campos ◽  
Francisco Gómez-Mula ◽  
...  
Keyword(s):  
Wave Propagation ◽  
Radio Wave ◽  
Empirical Model ◽  
Precision Agriculture ◽  
Wave Attenuation ◽  
Multipath Propagation ◽  
Field Tests ◽  
Radio Wave Propagation ◽  
Radio Waves ◽  
Vegetation Height

Spain is Europe’s leading exporter of tomatoes harvested in greenhouses. The production of tomatoes should be kept and increased, supported by precision agriculture to meet food and commercial demand. The wireless sensor network (WSN) has demonstrated to be a tool to provide farmers with useful information on the state of their plantations due to its practical deployment. However, in order to measure its deployment within a crop, it is necessary to know the communication coverage of the nodes that make up the network. The multipath propagation of radio waves between the transceivers of the WSN nodes inside a greenhouse is degraded and attenuated by the intricate complex of stems, branches, leaf twigs, and fruits, all randomly oriented, that block the line of sight, consequently generating a signal power loss as the distance increases. Although the COST235 (European Cooperation in Science and Technology - COST), ITU-R (International Telecommunications Union—Radiocommunication Sector), FITU-R (Fitted ITU-R), and Weisbberger models provide an explanation of the radio wave propagation in the presence of vegetation in the 2.4 GHz ICM band, some significant discrepancies were found when they are applied to field tests with tomato greenhouses. In this paper, a novel method is proposed for determining an empirical model of radio wave attenuation for vegetation in the 2.4 GHz band, which includes the vegetation height as a parameter in addition to the distance between transceivers of WNS nodes. The empirical attenuation model was obtained applying regularized regressions with a multiparametric equation using experimental signal RSSI measurements achieved by our own RSSI measurement system for our field tests in four plantations. The evaluation parameters gave 0.948 for R2, 0.946 for R2 Adj considering 5th grade polynomial (20 parameters), and 0.942 for R2, and 0.940 for R2 Adj when a reduction of parameters was applied using the cross validation (15 parameters). These results verify the rationality and reliability of the empirical model. Finally, the model was validated considering experimental data from other plantations, reaching similar results to our proposed model.

Prediction of Radio Wave Attenuation due to Clouds Using ANN and its Business Aspects

2021 ◽  
Author(s):  
Hitesh Singh ◽  
Vivek Kumar ◽  
Kumud Saxena ◽  
Boncho Bonev ◽  
Ramjee Prasad
Keyword(s):  
Radio Wave ◽  
Wave Attenuation

An ANN Model for Predicting Radio Wave Attenuation due to Rain and its Business Aspect

2021 ◽  
Author(s):  
Vivek Kumar ◽  
Hitesh Singh ◽  
Kumud Saxena ◽  
Boncho Bonev ◽  
Ramjee Prasad
Keyword(s):  
Radio Wave ◽  
Wave Attenuation ◽  
Ann Model
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