Search

Atmospheric transmittance in the band of 300–2000 μm was measured in the far i.r. Solar Observatory of Testa Grigia, 3480m above standard. These measurements are compared with the meteorological data observed at Plateau Rosa in the last 7yr.

When substantial harmonic power exists at the input of a radiating antenna, a lobe structure will result that may create a substantial interference problem. In addition, the privacy of the radiating source may be severely hampered. These harmonic fields are generally dependent upon: 1) the order of the harmonic relative to the geometry of the antenna, 2) the impedance the higher harmonic sees at the antenna input, 3) the power available at the given harmonic. For purposes of providing a measure of the seriousness of this problem, a harmonic analysis of a particular type of antenna configuration is examined, namely, that of a center-fed, thin half-wave dipole with director parallel to a reflecting plane. The active dipole is assumed ?0/4 away from the reflecting plane and the director ?0/8 away from the active dipole. As a criterion to determine the worst case situation, the antenna is assumed matched at each odd harmonic examined, and equal power is assumed fed at the input. The resulting field patterns show: 1) The presence of the director results in the introduction of sidelobes at the fundamental frequency in azimuthal plane. 2) The presence of the director plays less of a role the higher the harmonic. 3) In the meridian plane the sidelobes become more intense exceeding the forward-lobe intensity as the order of the harmonics is increased. 4) In the azimuthal plane, the sidelobe intensity approaches but does not exceed the forward-lobe intensity.

For many years the design of loop type directional couplers has relied heavily on experiment. One of the most common varieties has been the loop coupler much shorter than a wavelength and having a built-in termination (vestigial arm). In this paper the criteria for the design of loop couplers of any length are considered, and their application to either coaxial line or waveguide are discussed. The theoretical basis for design is established by first considering the theory of coupled transmission lines. Several designs which utilize a quarter-wavelength or shorter loops and which have very desirable features with regard to coupling, directivity, and band-width are illustrated. Typical performance of couplers having couplings of 20-40 db and directivities of over 30 db are presented.

Observed variations in D-zone propagation effects showed strong correlation with the occurrence of the solar eclipse of March 7, 1970.

The authors are reporting on a theoretical formulation supported by an experimental program, giving the electric field threshold necessary to produce minimum perceptible tracks in microwave spark chambers containing neon-argon mixtures. This formulation gives an electric field threshold which is within 10% of the authors experimental results.