ISSN:0048-6604    

DOI:10.1029/RS010i007p00655

年代:1975

数据来源: WILEY

摘要:

The life story of Marconi is too well documented to need detailed repetition, but there are certain facts about his early years which bear directly upon his quite remarkable success and indeed which relate to the early development of the subject of wireless telegraphy.Anyone looking at the early history of radio wave propagation and of Marconi's major role in it, cannot fail to be impressed with certain facts. Thus it is surely remarkable that in February 1896 when he first took his black wireless boxes to England, Marconi was only 21 years old and it is to be remembered that not only was he a very young man but he had had very little formal training in science. The second remarkable fact is that on 2 June 1896, i.e., within a few weeks of arriving in England (he was now just 22) he filed with the British Patent Office a provisional patent specification (the first of many) to safeguard his commercial interests in wireless communication. The third striking fact is that just one year later, in the summer of 1897, at the age of 23 he and his friends formed the Wireless Telegraph and Signal Company Limited (soon to be renamed the Marconi Wireless Telegraph Company) with an initial capital of £100,000. The shares in the new company were quickly subscribed; Marconi himself received £15,000 in cash and also held a large number of the share

ISSN:0048-6604    

DOI:10.1029/RS010i007p00657

年代:1975

数据来源: WILEY

摘要:

Developments in the theory of radio propagation in the first half of the twentieth century are briefly traced from early work on diffraction around the curved surface of the Earth to the discovery of the magnetosphere with the aid of whistlers. Attention is drawn to the possibility that Marconi may have been initially inspired by the concept of the Atlantic Ocean as a giant cost‐free telephone wire linking the European and American continent

ISSN:0048-6604    

DOI:10.1029/RS010i007p00665

年代:1975

数据来源: WILEY

摘要:

Short wave forecasting began in the late 1930s with rather crude, more global methods. The main steps of the development until the middle of the 1950s are described. Analytical methods have now replaced the original ones.

ISSN:0048-6604    

DOI:10.1029/RS010i007p00669

年代:1975

数据来源: WILEY

摘要:

The application of scattered radio waves to geophysical investigations is reviewed. The occurrence of ground scatter depends on the smoothness of the reflecting layer and limits for the inhomogeneity may be given. Direct backscatter occurs from field‐aligned irregularities in the auroral belt and movements may be derived from Doppler shift. The location and temporal movement of the two predominant precipitation belts are observed. Meteor scatter is strongly aspect sensitive and is used for deriving physical properties of the meteorites. The analysis of scattering in transequatorial short wave propagation points to a gravity wave induced system of eastward travelling field‐aligned inhomogeneities. Incoherent scatter has proved a successful tool for investigating many important parameters of the ionosphere. Satellite scintillations are helpful in mapping the irregularities of the electron content. They may be used for determining the height of the irregularities by radio wave holography. Scattering of microwaves on the ground is becoming a useful tool for geoexploration. Scattering processes in the troposphere are dealt with in a paper by C. G. Little in this is

ISSN:0048-6604    

DOI:10.1029/RS010i007p00681

年代:1975

数据来源: WILEY

摘要:

In the early days of upper atmosphere research, radio signals were the most useful diagnostic for studying ionospheric processes. During the space era, it has become possible to measure directly solar radiations that are screened from reaching the surface of the Earth, to measure the structure and composition of the upper atmosphere directly within situsensors, to conduct plasma experiments in space, to carry out remote sensing of the atmosphere from space, and to measure directly transionospheric radio propagation properties of the ionosphere. This recent dominance of space research methods in ionospheric research is becoming less marked as satellite opportunities diminish and greater emphasis is placed on studies of the ionosphere using new types of ground‐based instrumentation. Looking to the 1980s, the principal space flight opportunities will be associated with Spacelab, and new initiatives in ionospheric research will depend on a combined approach using all available methods for studying the dynamics and structure of the ionosphere. Future possibilities are outlined, with particular reference to new radio experiments on the ionospher

ISSN:0048-6604    

DOI:10.1029/RS010i007p00693

年代:1975

数据来源: WILEY

摘要:

A statistical analysis of 90 selected ionospheric storms has been carried out from MUF(ZERO)F2and MUF(3000)F2measured in Italy from 1958 to 1972. Typical behavior with regard to season, storm intensity, and statistical dispersion is shown for forecasting purposes.

ISSN:0048-6604    

DOI:10.1029/RS010i007p00699

年代:1975

数据来源: WILEY

摘要:

The dispersion relation of gravity waves propagating in a conducting atmosphere in the presence of a magnetic field has been evaluated. Extreme simplifying assumptions have been adopted in an effort to reach simple results. In this way, the applicability of the results to any real situation is highly doubtful. However, a qualitative and intuitive understanding of the influence of conductivity and magnetic field on the dispersion relation of gravity waves is more easily reached.

ISSN:0048-6604    

DOI:10.1029/RS010i007p00705

年代:1975

数据来源: WILEY

摘要:

Data on around‐the‐world (RTW) propagation obtained at Ithaca, N.Y., between the years 1965 and 1968 are described and discussed using a ray optics approach. The role of the oblique ionospheric shells that are known to exist near the 75° dip of the northern geomagnetic field in producing RTW echoes is emphasized. The possibility of utilizing RTW waves for ionospheric sounding is pointed

ISSN:0048-6604    

DOI:10.1029/RS010i007p00711

年代:1975

数据来源: WILEY

摘要:

The successes of Marconi in establishing radio communications, first with LF and VLF, and later with HF waves, are interpreted in terms of the (range)(rate)1/2relationship of space communications. The evolution of the technology from the late thirties to that associated with present‐day communications satellites characterized by high capacity and reliability is outline

ISSN:0048-6604    

DOI:10.1029/RS010i007p00719

年代:1975

数据来源: WILEY