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sheets of carbon uid (black writing uid) applied to sheets of paper were used—the amount of attenuation is adjust-able by changing the density of the applied carbon uid. e method causes wave absorption in two directions—transmission and reception. So, two-way rain attenuation—uplink and downlink—is simulated at one time. In addition, with this method, downlink rain margin losses are simu-lated very closely to actual situations because both rain attenuation and reception system noise temperature in-crease, simultaneously. However, note that, because such a shield board absorbs waves in a very short distance, the attenuation amount for the reception band (18 GHz band) is almost equal to the amount for the transmission (28 GHz band)—in such a sense, simulated situations by shield boards are dierent from actual situations.Figure 3 shows the simulation arrangement where a shield board is attached to a 1.2 m VSAT horn, and an example of a shield board.Figures 4 and 5 show the results of UPC operation tests conducted using a 1.2 m antenna and a 40 W SSPA VSAT. Figure 4 shows how the UPC operations in 6 M mode were veried to work, where IDU’s parameters were set as fol-lows:C/N0 limit = 83 dB;C/N0 margin @CLRS = 23 dB(Note: C/N0 margin @ CLRS is not directly settable. Instead, set ATT CONT @ CLRS to 29 dB, which is the value for the satellite link establishment request signal form an earth station for 1.5 M mode. So, when 6 M mode is used, the eect is deduced by the dierence of 6 M to 1.5 M—6 dB, the ratio of 6 M to 1.5 M—, and C/N0 mar-gin is adjusted to 23 dB.);THR rain fade (K1/K2) = 7:Coecient (K1) = 0;Coecient (K2) = 1.Note that estimated EIRP (e/w UPC) and estimated EIRP (w/o UPC) are the estimated EIRP of 1.2 m VSAT with UPC and that without UPC, respectively. Such EIRPs were obtained on the assumption that the uplink loss is equal to the loss in the downlink reference burst signal level. Also, packet loss (e/w UPC) and packet loss (w/o UPC) is respectively the packet loss for the data sent from 1.2 m VSAT to the target station in the cases of with UPC and without UPC. ose settings of parameters indicate the following for the UPC operation: the UPC is not in operation until the reception C/N0 goes down to 7 dB from 116 dB, the sum of C/N0 limit of 93 dB and C/N0 margin @ CLRS of 23 dB,—this means that Estimated EIRP (e/w UPC) and Estimated EIRP (w/o UPC) have the same value; when C/N0 goes down below the point, IDU transmission power goes up in the case of “with UPC,” for compensating the uplink rain attenuation. However, in the case of “with-out UPC,” because IDU transmission power stays at a constant level even when the C/N0 goes down, the esti-mated EIRP decreases along with the decline in C/N0, and Shield plate（Carbon） FiF3Experimental arrangement in which a shield board is attached to a 1.2 m VSAT hornFiF4　Verification of UPC operation (6 M mode)FiF5　Verification of UPC operation (51 M mode)793-2 Experiment Report for Rain Attenuation Compensation