On the Predicition of the Characteristic Parameters of Long-Distance Tropospheric Communication Links

Abstract

This paper describes a technique for determining probability distributions of parameters necessary for the design of tropospheric scatter communication links. The method, resulting from earlier studies of scatter propagation and the structure of the troposphere, utilizes information which is easily obtained from routine conventional radiosonde observations. Examples of probability distributions, based on radiosonde measurements from southwestern Norway, are presented and compared with existing experimental distributions.

Adaptive Antenna Control System

“…It can be verified that the maximum is at 6 = RG+ (corresponding to physically aiming the antenna just above horizon) and that It is clearly seen that there is only little difference between the results here and those of Gjessing and McCormick (1974). The experimental verification in their paper therefore also applies to our results.…”

“…5) are mostly at frequencies below and V is the total scattering volume. Typical values of the at-2 mospheric parameters a and r = L were described in the previous Gjessing and McCormick (1974) also report measurement of m in the range of 2-6 and give an empirical formula for m (Gjessing et.al., 1969) and an empirical distribution. However, the validity of these results is apparently limited (Sherwood and Suyemoto,1976) particularl since a strong frequency dependence of the equivalent measured m should be expected from the discussion above.…”

New formulas for tropospheric scatter path loss

“…while the receiving beam is narrow.The assumption of a narrow beam is seldom satisfied to the degree required here, but the results are still useful. They provide a simple bound on performance, and can be compared with similar results by other authors[Gjessing, 1969;Waterman, 1958;Gjessing and McCormick, 1974]. The derivations of the results below follow the same lines as exemplified by the derivation in section 3.…”

“…However, the turbulent scatter model is most useful at higher frequencies, and even at lower frequencies when concerned primarily with the weak-signal situation. The asymptotic form of the coupling loss is sometimes used to approximate the actual loss [Gjessing and McCormick, 1974]. Our results indicate that the coupling loss is very slow in approaching the asymptote and that use of the asymptotic result is much too optimistic (see Figures 3 and 4).…”