Ionospheric propagation in v. h. f. television Band I

摘要

In Europe, v.h.f television services are sometimes degraded by interference from distant co-channel transmitters The interference occurs most frequently during the summer months, mainly during the day and early evening, and may originate from points as much as 2500 km away It is caused by signals which propagate via the sporadic-E layer of the ionospherenIn order to study the effect of sporadic-P interference on v.h.f television broad¬casting, the European Broadcasting Union has carried out an extensive series of measurements, which were continued for 11 years in order to cover a complete sunspot cycle Measurements were made over 26 paths whose lengths varied between 900 and 2500 km, using frequencies between 40 and 60 MHznThe report describes the measurements, their analysis and the results obtained The final results were used to construct propagation curves for Europe and to derive a field-strength prediction method which may be used for the planning of future v hf broadcasting services.