Modern RF components don't need much design to realize commercial grade radios. We together have all the expertise needed to work a solution on our own. This is a cheap and valid solution that must be addressed before dismissing it too easily. His discussion is divided in points. We don't agree with the mono band solution.
Dual band is the road to uplinks and downlinks.
But not to dismiss this topic we do recognize the need for a low cost downlink. However we believe that for a project that will see the first hardware in a couple of years and that will be operated for at least a decade limiting it to monoband operation will impair seriously its effectiveness as education, divulgation and amateur tool. The performances for receivers are discussed Very useful data are provided to establish the receiver characteristics for packet reception aboard the ISS without the need to compensate for doppler. However the entire discussion is geared around commercial equipments. We don't believe commercial equipments is a valid solution for a permanent radio station.