11 UHF Band Path Loss Measurements Near Water Surface RFMTC 2011 October 4-5 Torbjörn Ödman (1), Peter Ankarson (2), Paul Hallbjörner (2) 1 Ericsson AB 2 SP Technical Research Institute of Sweden,

22 BACKGROUND Assignment from Inventech europe, Baltic, VINOVA Emergency Position Indicating Radio Beacon (EPIRB) Personal Location Beacon (PLB)

33 QUESTIONS OF RELEVANCE TO THESE SYSTEMS Which Frequency and polarization to use Can the free space or the ground reflex model be applicable Dependency of antenna heights above the water surface The path loss exponent of radio wave propagation

Measurements are performed at lake Vättern, Jönköping City map from Stadsarkivet, Jönköping,

55 REFERENCE MEASUREMENT SETUP

66 REFERENCE AND MEASUREMENT SET UP

77 POSITION OF ANTENNAS

88 RECEIVER

RESULT OF RECEIVED POWER AS FUNCTION OF HEIGHT

RESULT OF RECEIVED POWER AS FUNCTION OF DISTANCE

11 DISCUSSIONS In ground reflection model there exist distance and height dependence Calculated new exponents of height and distance Resulted in empirical model which describes better our raw data

12 DISTANCE DEPENDENCY Before the analysis, reference value at 2.56 m is subtracted from raw data. FREQUENCY ( MHz ) POLARIZATIONDISTANCE EXPONENT 200HORIZONTAL VERTICAL HORIZONTAL VERTICAL3.78

13 HEIGHT DEPENDENCY Before the analysis, reference value at 2.56 m is subtracted from raw data. FREQUENCY ( MHz ) POLARIZATIONHEIGHT EXPONENT 200HORIZONTAL VERTICAL HORIZONTAL VERTICAL HORIZONTAL VERTICAL1.2

14 CONCLUSION Exponent of height dependence in the ground reflection model is 2. Our result little bit weaker than 2. Exponent of distance dependence in the ground reflection model is 4. Our result little bit weaker than 4. For frequency of 200 MHz, In all measurements up to 800 meter the vertically polarized signal is less attenuated.

15 DIFFERENT ANTENNAS

16 THANK YOU Questions…