Regional Information Meeting and Workshop related to the RRC-06 for the administrations of the African countries Dakar, Senegal, April 2005 RRC Propagation Information Field strength prediction method Pham Nhu Hai Radiocommunication Bureau

RRC information meeting and workshop Dakar, Senegal April 2005 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 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 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 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 April 2005 RRC propagation zones

RRC information meeting and workshop Dakar, Senegal April MHz, 50% Land temperate

RRC information meeting and workshop Dakar, Senegal April MHz, 1% Land temperate

RRC information meeting and workshop Dakar, Senegal April MHz, 1% warm seas

RRC information meeting and workshop Dakar, Senegal 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 h 1 –Distance –Frequency –Percentage of time

RRC information meeting and workshop Dakar, Senegal 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 April 2005 Transmitting/base antenna height h 1 Land paths >= 15 km –h 1 = h eff (height over average terrain 3-15 km) Land paths < 15 km –h 1 = h a (height of the mast) for d<=3km –h 1 = h a + (h eff -h a )(d-3)/12 for 3 <d<15 km Sea paths –h 1 = h eff for h 1 >=1 m

RRC information meeting and workshop Dakar, Senegal April 2005 Field strength for a height h 1 h 1 <> 10, 20, 75, ….., 1200 m h 1 in the range 10 – 3000 m E = E inf + (E sup -E inf )log(h 1 /h inf )/log(h sup /h inf ) –h inf = 600 if h 1 > 1200 –h sup = 1200 if h 1 > 1200 h 1 in the range 0 – 10 m Negative h 1 (terrain clearance angle)

RRC information meeting and workshop Dakar, Senegal April 2005 Field strength = f (distance) If d does not coincide with one of the tabulation distances E = E inf + (E sup -E inf )log(d/d inf )/log(d sup /d inf )

RRC information meeting and workshop Dakar, Senegal April 2005 Field strength = f (frequency) If freq does not coincide with one of the nominal values (100, 600) E = E inf + (E sup -E inf )log(f/f inf )/log(f sup /f inf )

RRC information meeting and workshop Dakar, Senegal April 2005 Mixed path consideration 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

RRC information meeting and workshop Dakar, Senegal April 2005 FS prediction in 16 easy steps!!!

RRC information meeting and workshop Dakar, Senegal 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 ……………..