Accession Number:

ADA080035

Title:

Quiet Time Lowest Observable Frequency (QLOF) Calculation Program.

Descriptive Note:

Interim rept. Jan 78-Jan 79,

Corporate Author:

NAVAL OCEAN SYSTEMS CENTER SAN DIEGO CA

Personal Author(s):

Report Date:

1979-04-01

Pagination or Media Count:

16.0

Abstract:

The lowest observable frequency LOF for a specified hf circuit is important when one is specifying the propagation window for that circuit. This lowest frequency is an absorption controlled effect. The major cause of absorption at low and midlatitudes is the solar created ionospheric D-region. During quiet solar conditions this D-region responds directly to the amount of ionizing solar radiation reaching it. As shown in Bleiweiss 1970, 1972 and Argo and Hill 1977, this solar control is directly related to the solar zenith angle. Other relevant parameters are latitude, sunspot number, and season calculated from Julian day, which are all described in Argo and Hill 1977. The computer program listing presented in the appendix contains the necessary subroutines for calculating the quiet time LOF QLOF, and a sample control routine for driving the set of subroutines.

Subject Categories:

  • Radiofrequency Wave Propagation

Distribution Statement:

APPROVED FOR PUBLIC RELEASE