Comparison of ionospheric radio transmission forecasts with practical results

Abstract

The production of m.u.f. forecasts for oblique transmission involves numerous operations on basic information obtained at vertical incidence. At each stage, errors are introduced whose cumulative effect determines the difference between predicted and observed circuit performance. The sources of the errors are examined and tentative values assigned to them with special reference to F2-region.The computed value of the total error is compared with results obtained on commercial and Service circuits, and with observations made by other means. It is concluded that although, on the average, agreement is good, discrepancies remain which need further examination after the elimination of known sources of error.In a few cases, comparisons of predicted and actual times of fades due to ionospheric absorption have been made. Although the agreement between these times is reasonably good, it is believed that predictions of the actual field strength may be in error by large amounts.