A review of transhorizon propagation phenomena

Crane, Robert K.

doi:10.1029/rs016i005p00649

Cited by 18 publications

(7 citation statements)

References 25 publications

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“…The consistency in the agreement between the statistical results and the existing propagation theory is proof of the validity of the approach, and this paper explains the details. It should be noted, however, that the possible use of transhorizon signal amplitude signatures, either on their own or combined with radar observations, has already been pointed out by DuCastel [ 1966] and Crane [ 1981 ]. The same applies to more recent observations by Tawfik and Vilar [ 1993].…”

Section: Introductionmentioning

confidence: 76%

“…Laminar flow in the atmosphere may result in layer structures in the lower part of the troposphere [Bean and Dutton, 1968]. These layers can extend up to tens of kilometers in the horizontal direction while having only a few meters in thickness, as observed by many experimenters [e.g., Saxton et al, 1964;Gossard, 1984;Crane, 1981 ]. The layers have irregular boundaries, are variable in position and size, and if this situation occurs within the common volume, the layers may give rise to reflection from the incident radio waves into the receiver direction.…”

Section: Layer Reflectionmentioning

confidence: 95%

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Anomalous transhorizon propagation and meteorological processes of a multilink path

Shen¹

1995

Radio Science

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An event‐based approach is developed and applied to 3 years of data of a four link transhorizon path over the English Channel (La Manche). The signal enhancements (events) observed on the chart recordings during anomalous propagation are selected and, according to their dynamical signatures, categorized into three main patterns of ducting, layer reflection, and high k factor diffraction. The statistical analysis carried out on this event basis gives the correlation between the signal levels of different links and the cross correlation between signal levels and local N index derived from surface meteorological monitoring. The results reveal the fundamental properties of the anomalous propagation regimes. Using case studies of several interesting events, the meteorological processes and resultant impact on transhorizon transmission are also explained. This extensive work contributes to a better understanding of anomalous propagation mechanisms present in transhorizon links.

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Section: Introductionmentioning

confidence: 76%

Section: Layer Reflectionmentioning

confidence: 95%

Anomalous transhorizon propagation and meteorological processes of a multilink path

Shen¹

1995

Radio Science

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“…These applications use point to area networks, which are vulnerable to interference from other users, so it is important to have a robust and accurate means of estimating the range of a signal. This range of a UHF signal can be enhanced by a number of mechanisms [ Crane , 1981; Bean and Dutton , 1968] which depend on prevailing meteorological conditions, and the complexity of the situation is greater in coastal areas where enhanced transhorizon propagation is particularly prevalent. The data presented here provide important information about the behaviour of the signal strength for the top few percent of the time, which can only be obtained from a long term study, and also gives insight into the diurnal and annual variations of the data, which might be used for adaptive power control to mitigate against interference.…”

Section: Introductionmentioning

confidence: 99%

Signal strength variations at 2 GHz for three sea paths in the British Channel Islands: Observations and statistical analysis

2007

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[1] Measurements of signal strength are reported for a study of UHF propagation on three transhorizon sea paths in the British Channel Islands. Enhancements of up to 30 dB from the mean occur for periods of hours or days, especially in the summer, and constitute about 5% of the overall data. The probability distribution of received power is t abulated for the three paths and various antenna heights, and is compared with predictions of signal strength using ITU-R Recommendation P.1546-2. The difference between median and upper decile in the data is much less than predicted, whereas the difference between upper decile and the upper percentile is much greater than predicted.

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“…Since the 1940s, a large number of experimental investigations into the radio wave propagation have been performed [1][2][3][4][5][6]. These experiments indicate that microwave signals can propagate beyond the line of sight, especially in the marine atmospheric environment.…”

Section: Introductionmentioning

confidence: 99%

C band transhorizon signal characterisations in evaporation duct propagation environment over Bohai Sea of China

Guo

Zhao

Zhang

et al. 2019

IET Microwaves, Antennas & Propagation

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Evaporation duct is an anomalous mechanism of transhorizon propagation in marine and coastal regions. In order to better understand the characteristics of signal fading, a C band signal transhorizon propagation experiment was carried out with a 107 km path length over the Bohai Sea of China. Using an iron tower with meteorological and oceanographic (METOC) sensors at multiple altitudes, a direct diagnostic method of evaporation duct is presented. The dependence of signal strength on evaporation duct height, antenna height, and METOC parameters is analysed. The experimental results indicate that the signal strength tends to be linearly dependent on the evaporation duct height when the transmitter and receiver antennas are submerged within the duct layer. Normally, the signal strength is stronger when the relative humidity is lower. Stronger signal strength tends to occur under near‐neutral or stable atmospheric conditions or when the air–sea temperature difference is higher. The results indicate that the signal strength distribution of fast fading is close to Rayleigh distribution, and the probability density of fade slope is symmetric at 0 dB/s. These results have important implications for the design of ducting communications system.

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A review of transhorizon propagation phenomena

Cited by 18 publications

References 25 publications

Anomalous transhorizon propagation and meteorological processes of a multilink path

Anomalous transhorizon propagation and meteorological processes of a multilink path

Signal strength variations at 2 GHz for three sea paths in the British Channel Islands: Observations and statistical analysis

C band transhorizon signal characterisations in evaporation duct propagation environment over Bohai Sea of China

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