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Regional Information Meeting and Workshop related to the RRC-06 for the administrations of the African countries Dakar, Senegal, 25-29 April 2005. RRC Propagation Information Field strength prediction method. Pham Nhu Hai Radiocommunication Bureau. Outline. Overview – propagation models
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Regional Information Meeting and Workshop related to the RRC-06 for the administrations of the African countriesDakar, Senegal, 25-29 April 2005 RRC Propagation Information Field strength prediction method Pham Nhu Hai Radiocommunication Bureau
Outline • Overview – propagation models • RRC propagation curves/tables • RRC propagation zones • Propagation prediction method • Propagation for other services RRC information meeting and workshop Dakar, Senegal 25-29 April 2005
Propagation models • Path specific • Terrain data • Time consuming • Accurate but no agreed methods for broadcasting • Path general • General terrain data required (effective heights) • Fast easy to use • ITU conference (ITU-R P 370, 529, 1146 and 1546) RRC information meeting and workshop Dakar, Senegal 25-29 April 2005
One propagation model! • ITU-R P.1546 replaces • ITU-R P.370 (BC VHF/UHF) • ITU-R P.529 (LM VHF/UHF) • ITU-R P.1146 (LM & BC, 1-3 GHz) • Path general methods • 30 MHz – 3000 MHz • 1 km – 1000 km • 1% - 50% percentage of time RRC information meeting and workshop Dakar, Senegal 25-29 April 2005
RRC propagation model • Set of propagation curves/tables of field strength (dBu) vs distance (km) • Heights of transmitting/base antenna • 100, 600 and 2000 MHz • 1%, 10% and 50% • Receiving antenna height of 10m in open area • Detailed inter/extrapolation procedures • Other percentage of time • Other frequencies • Other transmitting/base antenna heights RRC information meeting and workshop Dakar, Senegal 25-29 April 2005
RRC propagation zones RRC information meeting and workshop Dakar, Senegal 25-29 April 2005
600 MHz, 50% Land temperate RRC information meeting and workshop Dakar, Senegal 25-29 April 2005
600 MHz, 1% Land temperate RRC information meeting and workshop Dakar, Senegal 25-29 April 2005
600 MHz, 1% warm seas RRC information meeting and workshop Dakar, Senegal 25-29 April 2005
Propagation prediction method • Maximum field strength values • Determine transmitting/base antenna height • Interpolation of field strength as a function of • Transmitting/base height h1 • Distance • Frequency • Percentage of time RRC information meeting and workshop Dakar, Senegal 25-29 April 2005
Propagation prediction method (2) • Mixed paths • Correction for receiving/mobile antenna height • Correction of terrain clearance angle • Location variability in land area-coverage prediction • FS prediction in 16 easy steps!!!! RRC information meeting and workshop Dakar, Senegal 25-29 April 2005
Transmitting/base antenna height h1 • Land paths >= 15 km • h1= heff (height over average terrain 3-15 km) • Land paths < 15 km • h1=ha (height of the mast) for d<=3km • h1= ha + (heff-ha)(d-3)/12 for 3 <d<15 km • Sea paths • h1= heff for h1 >=1 m RRC information meeting and workshop Dakar, Senegal 25-29 April 2005
Field strength for a height h1 • h1 <> 10, 20, 75,….., 1200 m • h1 in the range 10 – 3000 m E = Einf + (Esup-Einf)log(h1/hinf)/log(hsup/hinf) • hinf = 600 ifh1> 1200 • hsup = 1200 ifh1> 1200 • h1 in the range 0 – 10 m • Negative h1 (terrain clearance angle) RRC information meeting and workshop Dakar, Senegal 25-29 April 2005
Field strength = f (distance) • If d does not coincide with one of the tabulation distances E = Einf + (Esup-Einf)log(d/dinf)/log(dsup/dinf) RRC information meeting and workshop Dakar, Senegal 25-29 April 2005
Field strength = f (frequency) • If freq does not coincide with one of the nominal values (100, 600) E = Einf + (Esup-Einf)log(f/finf)/log(fsup/finf) RRC information meeting and workshop Dakar, Senegal 25-29 April 2005
ITU-R P.370 Based on percentage of land and sea path Shows unrealistic “recovery effect” Sea curves show large variation wrt effective heights RRC (P.1546) Longest contiguous path is important (breaking down ducting) Avoid “recovery effect” Consistent set of sea curves Mixed path consideration RRC information meeting and workshop Dakar, Senegal 25-29 April 2005
FS prediction in 16 easy steps!!! RRC information meeting and workshop Dakar, Senegal 25-29 April 2005
Conclusions • One propagation model • Based on ITU-R P.1546 • Data available in curves and tables • Better prediction for sea paths • Step-by-step FS prediction method • TGFC…………….. RRC information meeting and workshop Dakar, Senegal 25-29 April 2005