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Old 04-06-2011, 15:02   #91
olegsher
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Join Date: Jul 2009
Location: Mountain View, CA
Posts: 2
Really good point!!
But this was done on purpose - the SATCOM system is asymmetrical - the Satellite Vehicle Platforms (Satellites) are more powerful (150W) than ground stations (5-20-50W). Additionally, SWR is much more important on the transmit side - we can pull out the signal lost on the receive side with som LNA (Low Noise Amplifier), but you cannot do anything with the transmit power lost due to the impedance mismatch.
Ground Stations Rx frequencies are 240-270Mhz, Tx Frequencies 270-320Mhz.
The optimization on SWR was favoring Tx portion of the band with the ratio of 4:1 over the SWR on Rx side.
Quite opposite was done for the Gain - the geometry was optimized to get the maximum gain on Rx portion of the SATCOM band.
The final optimization was to find the best balance between those two contradicting requirements.
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