Page Comparison

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• The Extended Hata model assumes simply the height of transmitting antenna above ground.
• The P.1546 model assumes that the height of transmitting antenna (h1, ht) is the effective height above the average height of terrain over the propagation path (taken between 3-15 km). In that regard it should be noted that SEAMCAT by itself does not have any knowledge about the actual terrain, therefore user should carefully consider the appropriate value of transmitting antenna height, following guidance in Rec. ITU-R P.1546-1. 

On the other hand, it should be noted that the P.1546 model does not have a distinction between urban and rural propagation conditions except when calculating correction for receiving antenna height. Thus, the setting of URBAN, SUBURBAN or RURAL environment when selecting P.1546 model simply leads to an assumption of certain height of local clutter, surrounding the receiver antenna. This is then compared with the height of receiver antenna and depending on their relationship, the appropriate correction will be made. For example, if the receiver antenna height is less than the assumed height of local clutter, then the propagation loss will increase.

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The figure below shows an example of how the median propagation loss calculated with P.1546 model would change depending on the height of receive antenna (h₂), and how it compares with the corresponding Extended Hata model results (the curves are for 600 MHz, 50% time, 50% locations, default local clutter setting in P.1546). 

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When the height of receiver antenna h2 in P.1546 is set to 1.5 m, which is much below the assumed height of local clutter (the default value of 10 dB was used in these simulations), then the propagation loss is much higher (by almost 20 dB) than the one generated with P.1546 for h2=10 m (i.e. when receiver antenna height was set equal to the height of local clutter). In the latter case, the P.1546 model predicts losses that are quite close to the results produced with the Extended Hata model, especially for shorter distances.