The extraordinary wave mode: neglected in current practical literature for HF NVIS communications

Walden, Marcus C.

doi:10.1049/cp.2009.0028

Cited by 4 publications

(6 citation statements)

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“…As can be seen, NVIS propagation is possible when fxF2 exceeds the operating frequency. This conforms to theory [Budden, 1985;Walden, 2009].…”

Section: Near Vertical Incidence Skywave B a Witvliet Interaction Osupporting

confidence: 90%

“…Johnson [2007] compares measured 24-hour NVIS link availability with VOACAP [Perkiomaki, 2003[Perkiomaki, -2014 propagation predictions on several frequencies between 3 and 9 MHz during a solar minimum. Walden [2009] reports that several propagation prediction models neglect the effect of the extraordinary wave. In [ITU-R Rec.…”

Section: Propagation Predictionmentioning

confidence: 99%

“…These characteristic waves, the ordinary and extraordinary wave, have circular polarization of opposite sense. They follow a different path through the ionosphere and experience different attenuation and show different behavior [Walden, 2009]. They therefore produce two slightly different traces in the ionogram of Figure 4.2, shown as green and red traces.…”

Section: Ionospheric Radio Wave Propagationmentioning

confidence: 99%

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Near vertical incidence skywave

Witvliet

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“…As can be seen, NVIS propagation is possible when fxF2 exceeds the operating frequency. This conforms to theory [Budden, 1985;Walden, 2009].…”

Section: Near Vertical Incidence Skywave B a Witvliet Interaction Osupporting

confidence: 90%

Section: Propagation Predictionmentioning

confidence: 99%

Section: Ionospheric Radio Wave Propagationmentioning

confidence: 99%

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Near vertical incidence skywave

Witvliet

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“…Johnson [47] compares measured 24 h NVIS link availability with VOACAP [48] simulations on several frequencies between 3 and 9 MHz during a solar minimum. Walden [49] reports that several propagation prediction models neglect the effect of the extraordinary wave. In [50] basic recommendations and formula for ionospheric propagation prediction are provided, and in [51] a state-of-the-art ionospheric prediction model is described.…”

Section: Propagation Predictionmentioning

confidence: 99%

Radio communication via Near Vertical Incidence Skywave propagation: an overview

Witvliet

Alsina-Pagès

2017

Telecommun Syst

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“…These characteristic waves, namely, the ordinary and extraordinary wave, have circular polarization of opposite sense. They follow a different path through the ionosphere and experience different attenuation and show different behavior [26]. They therefore produce two slightly different traces in the ionogram in Figure 2, which are shown as green and red traces.…”

Section: Ionospheric Radio Wave Propagationmentioning

confidence: 99%

Near Vertical Incidence Skywave Propagation: Elevation Angles and Optimum Antenna Height for Horizontal Dipole Antennas

Witvliet

Maanen

Petersen

et al. 2015

IEEE Antennas Propag. Mag.

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Near Vertical Incidence Skywave (NVIS) communication uses the ionosphere as a reflector to cover a continuous area with a radius of at least 150 km around the transmitter, on frequencies typically between 3 and 10 MHz. In developing countries, in areas lacking any other telecommunication infrastructure, it is used on a daily basis for voice and data communication. It may also be used in ad-hoc emergency (disaster) communication in other regions. This paper proposes optimum heights above ground for horizontal dipole antennas for NVIS, based on simulations and empirical data. First, the relationship between elevation angle and skip distance is obtained using ionospheric ray tracing. The high elevation angles found by simulation are confirmed by elevation angle measurements using a professional radio direction finder. The measurements also show the dominance of NVIS over ground wave propagation starting at a short distance. For these elevation angles, the optimum receive and transmit antenna heights above ground are derived using antenna simulations. A distinction is made between optimum transmit signal strength and optimum received signal-to-noise ratio (SNR). These optima are verified experimentally, demonstrating a novel evaluation method that can be used in the presence of the fading typical for ionospheric propagation. For farmland soil ( % 20 mS/m, " r % 17) the optimum height above ground for the transmit antenna is 0.18-0.22. If the antenna is lowered to 0.02 a transmit signal loss of 12 dB occurs. This corresponds with the theory. The receive antenna height, however, while appearing uncritical in the simulations, showed a clear optimum at 0.16 and a 2-7 dB SNR deterioration when lowered to 0.02.

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The extraordinary wave mode: neglected in current practical literature for HF NVIS communications

Cited by 4 publications

References 0 publications

Near vertical incidence skywave

Near vertical incidence skywave

Radio communication via Near Vertical Incidence Skywave propagation: an overview

Near Vertical Incidence Skywave Propagation: Elevation Angles and Optimum Antenna Height for Horizontal Dipole Antennas

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