[eagle] New U-band receiver requirements document

I've updated the requirements document on the U-band receiver web page. This version accounts for text-mode uplinks but that doesn't change the requirements significantly. I did make assumptions about the antenna pattern (the same as before) and the text-mode uplink spacing and bandwidth (these are new). I've allowed for splitting the receiver into two modules in case this is needed to solve the thermal problem. I've also changed the requirements for PAVE PAWS interference abatement by assuming that the SAW filters will be the primary mechanism used. This may allow lower DC power consumption.

All of the requirements should be verifed by those interfacing to the receiver.

73,

John KD6OZH