1. A dual band down converter receiving system for simultaneously receiving from a feed first microwave signals in a first frequency range and second microwave signals in a second frequency range, said system comprising: a printed circuit board, said printed circuit board having a first ground plane on a first surface, a second ground plane on a second surface opposing said first surface, and an input end, means connected to said feed for delivering the first microwave signals over a first path and the second microwave signals over a second path, a first filter mounted on said first surface of said input end of said printed circuit board and connected to said first path for filtering said first microwave signals, a second filter mounted on said second surface opposing said first surface of said input end of said printed circuit board and connected to said second path for filtering said second microwave signals, said delivering means including: (i) a first through-board-connection in said printed circuit board, (ii) a first trace on said first surface of said printed circuit board connected between said through-board-connection and the input of said first filter, said first trace being a one-half wavelength open stub at the center frequency of said second frequency range, and (iii) a second trace on said second opposing surface of said printed circuit board connected between said through-board-connection and the input of said second filter, said second trace having a length less than one-quarter of the wavelength of the center frequency of said first frequency range, means connected to the outputs of said first and second filters for combining said first microwave signals and said second microwave signals at a common output, said combining means including: (i) a second through-board-connection in said printed circuit board, (ii) a first trace on said first surface of said printed circuit board connected between said second through-board-connection and the output of said first filter, and (iii) a second trace on said second opposing surface of said printed circuit board connected between said second through-board-connection and the output of said second filter.