ATTENUATION OF RADIO FREQUENCY WAVES THROUGH THE EARTH

Geophysics ◽  
1952 ◽  
Vol 17 (2) ◽  
pp. 193-217 ◽  
Author(s):  
W. C. Pritchett
Keyword(s):  
Radio Frequency ◽  
Normal Values ◽  
Electromagnetic Theory ◽  
Deep Penetration ◽  
Radio Waves ◽  
Attenuation Constant ◽  
A Value ◽  
The Earth ◽  
Radio Frequency Waves

Evidence has been presented by several investigators indicating the possibility that radio waves penetrate sufficiently deep into the earth to be useful in prospecting for oil. Conventional electromagnetic theory used with normal values of the earth constants indicates, however, that the attenuation is too great to allow the signal to be used after propagation through significant distances of shale. To settle the above question an experiment was conceived and carried out in which the signal level in the earth was measured at various distances from a battery‐operated transmitter operating at 1,652 kc suspended in an uncased, mud‐filled hole by a mud‐saturated rope. The mud resistivity was matched to that of the 40 foot thick shale section used in order that the entire immediate region would be as nearly as possibly homogeneous. The receiver was also battery‐operated and suspended by a cable in other similar mud‐filled holes at various distances from the first hole. The attenuation constant in shale was found to be 0.231 nepers/foot (2 db/foot), which is much too large to give any hope of deep penetration. A few measurements in a limestone section gave a value of 0.086 nepers/foot, which is also too large to be useful. Although these values are quite high, they are lower than theory predicts for these earth resistivities by a factor of about two.

PROPAGATION OF RADIO FREQUENCY ENERGY THROUGH THE EARTH

Geophysics ◽  
1954 ◽  
Vol 19 (3) ◽  
pp. 459-477 ◽  
Author(s):  
F. M. McGehee
Keyword(s):  
New Mexico ◽  
Radio Frequency ◽  
Propagation Characteristics ◽  
Attenuation Constant ◽  
Radio Frequency Energy ◽  
The Earth ◽  
Similar Series ◽  
Set Up ◽  
Good Agreement ◽  
Made In

Measurements have been made of some propagation characteristics in the earth of 1,614 and 1,700 kc radio frequency energy. The experiments were conducted at Carlsbad Caverns, New Mexico, and Mammoth Cave, Kentucky. Transmitters were set up on the surface 710 ft above an unwired tunnel in Carlsbad Caverns and the signal strength was measured at many points in the tunnels. A similar series of measurements was made in Mammoth Cave in a tunnel 270 ft below the surface. The data show that the attenuation constant is about 0.012 and 0.02 to 0.064 neper/meter at the two locations respectively. These values are in good agreement with theory.

A Theoretical Discussion of the Electrical Properties of the Soil

1931 ◽  
Vol 27 (2) ◽  
pp. 268-276 ◽  
Author(s):  
F. W. G. White
Keyword(s):  
Electrical Properties ◽  
Effective Conductivity ◽  
Theoretical Discussion ◽  
Radio Waves ◽  
A Value ◽  
The Earth

It has been shown by Ratcliffe and White that the effective specific inductive capacity (ε) and the effective conductivity (σ) of soil placed, as dielectric, in a simple condenser vary in a marked manner with frequency. The range of frequency used was from 0·1 × 106 cycles per second to 10 × 106 cycles per second. It was found that at 6·1 × 106 cycles per second the specific inductive capacity was very large (about 40 e.s.u.) and that it decreased to a value of about 12 e.s.u. at 10 × 106 cycles per second. This latter value agrees with the value found in experiments on the propagation of short radio waves over the surface of the earth. The effective conductivity of the soil had a low value at 0·1 × 106 cycles per second but increased rapidly to a constant value for frequencies above 3 × 106 cycles per second.

Ultra Short Baseline (USBL) Calibration for Positioning of Underwater Objects

2019 ◽  
Vol 2 (2) ◽  
pp. 73-85
Author(s):  
Bagus Septyanto ◽  
Dian Nurdiana ◽  
Sitti Ahmiatri Saptari
Keyword(s):  
Acoustic Wave ◽  
Scale Factor ◽  
Positioning System ◽  
Radio Waves ◽  
Short Baseline ◽  
Error Angle ◽  
Satellite Navigation System ◽  
The Earth ◽  
Underwater Positioning ◽  
Radio Signals

In general, surface positioning using a global satellite navigation system (GNSS). Many satellites transmit radio signals to the surface of the earth and it was detected by receiver sensors into a function of position and time. Radio waves really bad when spreading in water. So, the underwater positioning uses acoustic wave. One type of underwater positioning is USBL. USBL is a positioning system based on measuring the distance and angle. Based on distance and angle, the position of the target in cartesian coordinates can be calculated. In practice, the effect of ship movement is one of the factors that determine the accuracy of the USBL system. Ship movements like a pitch, roll, and orientation that are not defined by the receiver could changes the position of the target in X, Y and Z coordinates. USBL calibration is performed to detect an error angle. USBL calibration is done by two methods. In USBL calibration Single Position obtained orientation correction value is 1.13 ̊ and a scale factor is 0.99025. For USBL Quadrant calibration, pitch correction values is -1.05, Roll -0.02 ̊, Orientation 6.82 ̊ and scale factor 0.9934 are obtained. The quadrant calibration results deccrease the level of error position to 0.276 - 0.289m at a depth of 89m and 0.432m - 0.644m at a depth of 76m

Scattering of radio frequency waves by density filaments

2020 ◽  
Vol 175 (11-12) ◽  
pp. 976-980
Author(s):  
Abhay K. Ram ◽  
K. Hizanidis ◽  
F. Bairaktaris ◽  
A. Papadopoulos ◽  
S.-I. Valvis
Keyword(s):  
Radio Frequency ◽  
Radio Frequency Waves

scholarly journals Onboard Radio Frequency Interference as the Origin of Inter-Satellite Biases for Microwave Humidity Sounders

2019 ◽  
Vol 11 (7) ◽  
pp. 866 ◽  
Author(s):  
Imke Hans ◽  
Martin Burgdorf ◽  
Stefan A. Buehler
Keyword(s):  
Time Series ◽  
Radio Frequency ◽  
Time Dependent ◽  
Radio Frequency Interference ◽  
Climate Variables ◽  
Compelling Evidence ◽  
Climate Data ◽  
The Earth ◽  
Correction Scheme

Understanding the causes of inter-satellite biases in climate data records from observations of the Earth is crucial for constructing a consistent time series of the essential climate variables. In this article, we analyse the strong scan- and time-dependent biases observed for the microwave humidity sounders on board the NOAA-16 and NOAA-19 satellites. We find compelling evidence that radio frequency interference (RFI) is the cause of the biases. We also devise a correction scheme for the raw count signals for the instruments to mitigate the effect of RFI. Our results show that the RFI-corrected, recalibrated data exhibit distinctly reduced biases and provide consistent time series.

Automated Determination of the Position of Ships by Satellites

1967 ◽  
Vol 20 (03) ◽  
pp. 281-285
Author(s):  
H. C. Freiesleben
Keyword(s):  
Celestial Body ◽  
World Wide ◽  
Artificial Satellites ◽  
Radio Waves ◽  
The Moon ◽  
Position Determination ◽  
The Earth ◽  
Navigational Aids ◽  
Automated Determination

It has recently been suggested that 24-hour satellites might be used as navigational aids. To what category of position determination aids should these be assigned ? Is a satellite of this kind as it were a landmark, because, at least in theory, it remains fixed over the same point on the Earth's surface, in which case it should be classified under land-based navigation aids ? Is it a celestial body, although only one tenth as far from the Earth as the Moon ? If so, it is an astronomical navigation aid. Or is it a radio aid ? After all, its use for position determination depends on radio waves. In this paper I shall favour this last view. For automation is most feasible when an object of observation can be manipulated. This is easiest with radio aids, but it is, of course, impossible with natural stars.At present artificial satellites have the advantage over all other radio aids of world-wide coverage.

Effect of radio frequency waves on plasma

2020 ◽  
Vol 175 (11-12) ◽  
pp. 1037-1041
Author(s):  
C. Standfield ◽  
T. Smith ◽  
I. Mombo ◽  
M. Rhinehart ◽  
P. Adegbaye ◽  
...  
Keyword(s):  
Radio Frequency ◽  
Radio Frequency Waves

scholarly journals Precision Pulsar Timing with NASA's Deep Space Network

2015 ◽  
Vol 11 (A29B) ◽  
pp. 367-369
Author(s):  
Lawrence Teitelbaum ◽  
Walid Majid ◽  
Manuel M. Franco ◽  
Daniel J. Hoppe ◽  
Shinji Horiuchi ◽  
...  
Keyword(s):  
Low Frequency ◽  
Radio Waves ◽  
Deep Space ◽  
Radio Pulsars ◽  
Deep Space Network ◽  
Space Network ◽  
The Earth ◽  
Pulsar Timing ◽  
Initial Results ◽  
Stable Rotation

AbstractMillisecond pulsars (MSPs) are a class of radio pulsars with extremely stable rotation. Their excellent timing stability can be used to study a wide variety of astrophysical phenomena. In particular, a large sample of these pulsars can be used to detect low-frequency gravitational waves. We have developed a precision pulsar timing backend for the NASA Deep Space Network (DSN), which will allow the use of short gaps in tracking schedules to time pulses from an ensemble of MSPs. The DSN operates clusters of large dish antennas (up to 70-m in diameter), located roughly equidistant around the Earth, for communication and tracking of deep-space spacecraft. The backend system will be capable of removing entirely the dispersive effects of propagation of radio waves through the interstellar medium in real-time. We will describe our development work, initial results, and prospects for future observations over the next few years.

scholarly journals Mantle Rayleigh waves from the Kamchatka earthquake of November 4, 1952*

1954 ◽  
Vol 44 (3) ◽  
pp. 471-479
Author(s):  
Maurice Ewing ◽  
Frank Press
Keyword(s):  
Internal Friction ◽  
Rayleigh Waves ◽  
Shear Velocity ◽  
Velocity Curve ◽  
The Core ◽  
Long Period ◽  
A Value ◽  
The Earth ◽  
Dispersion Data ◽  
Kamchatka Earthquake

Abstract Mantle Rayleigh waves from the Kamchatka earthquake of November 4, 1952, are analyzed. The new Palisades long-period vertical seismograph recorded orders R6–R15, the corresponding paths involving up to seven complete passages around the earth. The dispersion data for periods below 400 sec. are in excellent agreement with earlier results and can be explained in terms of the known increase of shear velocity with depth in the mantle. Data for periods 400-480 sec. indicate a tendency for the group velocity curve to level off, suggesting that these long waves are influenced by a low or vanishing shear velocity in the core. Deduction of internal friction in the mantle from wave absorption gives a value 1/Q = 370 × 10−5 for periods 250-350 sec. This is a little over half the value reported earlier for periods 140-215 sec.

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