MoPro Chapter 3.6

3.6 Frequency Scaling Considerations

The frequency scaling formulation applied to the ERS model is applicable between UHF (870 MHz) and S-Band (3 GHz) and is given by

for and :

,
(3-20)

where and where is the attenuation expressed in dB at the frequency f (expressed in GHz). The frequency scaling in the EERS model is given by exponent factor in (3-1).

Figure 3-23 depicts a comparison using both frequency scaling formulations and the measurements of Bundrock and Harvey [1988]. The open circled points correspond to the formulation (3-20) and the solid points represent the formulation (3-1) with corresponding to the L-Band frequency (1.55 GHz) and attenuation values of Bundrock and Harvey. That is, the estimated points shown were derived from the middle curve corresponding to the L-Band measured distribution. Since both scaling methods give approximately similar results, it is suggested that (3-1) be used for simplicity over the entire frequency range (up to 20 GHz), although both are applicable between UHF and S-Band.

Figure 3-23: Fade distributions at L-Band, S-Band and UHF measured by Bundrock and Harvey [1988] (solid curves). The open circular and solid circular points represent the ERS and the EERS frequency scaling estimates, respectively.

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