where: For the succeeding three hours (n = 1, 2 and 3), is calculated by: fL (38) The newly recalculated values replace the initial values only if they are larger. Once all fL fL fL values in a 24-hour period are calculated, the current hour value is selected and the calculation fL fL is complete. 5.3.3 Estimation of the field strength Etl The resultant median field strength is given by: Etl 30.0 + + + dB(1 V/m) (39) Pt Gtl Gap Ly – – where is the free-space field strength for 3 MW e.i.r.p. In this case: E0 = 139.6 20 log dB(1 V/m) (40) E0 p – where: is calculated using equations (19) and (13) with = 300 km p hr largest value of transmitting antenna gain at the required azimuth in the Gtl: elevation range 0° to 8° (dB) increase in field strength due to focusing at long distances given as: Gap: dB (41) As from the above formula tends to infinity when is a multiple of it is limited to the Gap D R0, value of 15 dB. a term similar in concept to The present recommended value is dB Ly: Lz. –0.14 NOTE 1 It should be noted that the value of is dependent on the elements of the prediction method, so Ly – that any changes in those elements should be accompanied by revision of the value Ly mean of the values of electron gyrofrequency determined at both control points fH: MUF (see § 5.3.1) fM: (see § 5.3.2). 5.4 Paths between 7 000 and 9 000 km In this distance range the median sky-wave field strength is determined by interpolation between Eti values and is the root-sum-squared field strength given by equation (28) and refers to a Es El. Es El composite mode as given by equation (39). dB(1 V/m) (42) with: where: and
where: For the succeeding three hours (n = 1, 2 and 3), fL is calculated by: (38) The newly recalculated fL values replace the initial fL values only if they are larger. Once all fL values in a 24-hour period are calculated, the current hour fL value is selected and the fL calculation is complete. 5.3.3 Estimation of the field strength Etl The resultant median field strength Etl is given by: – 30.0 + Pt + Gtl + Gap – Ly dB(1 V/m) (39) where E0 is the free-space field strength for 3 MW e.i.r.p. In this case: E0 = 139.6 – 20 log p dB(1 V/m) (40) where: p is calculated using equations (19) and (13) with hr = 300 km Gtl: largest value of transmitting antenna gain at the required azimuth in the elevation range 0° to 8° (dB) Gap: increase in field strength due to focusing at long distances given as: dB (41) As Gap from the above formula tends to infinity when D is a multiple of R0, it is limited to the value of 15 dB. Ly: a term similar in concept to Lz. The present recommended value is –0.14 dB NOTE 1 – It should be noted that the value of Ly is dependent on the elements of the prediction method, so that any changes in those elements should be accompanied by revision of the Ly value fH: mean of the values of electron gyrofrequency determined at both control points fM: MUF (see § 5.3.1) (see § 5.3.2). 5.4 Paths between 7 000 and 9 000 km In this distance range the median sky-wave field strength Eti is determined by interpolation between values Es and El. Es is the root-sum-squared field strength given by equation (28) and El refers to a composite mode as given by equation (39). dB(1 V/m) (42) with: where: and
R-REC-P.533-13-201507-I!!MSW-E.docx