[hpsdr] HPSDR front end

[Phil Harman]

Hi Francis,

You asked 

"What is the front end of this FPGA machine you guys are building.?"

There are two options being considered at the moment. The first is direct A/D at the antenna using the Mercury board ( see http://hpsdr.net under Mercury for a brief description) and a more conventional mixer +  local oscillator down converter to  the  Janus  "sound card replacement" A/D converter. 

At the moment it looks very unlikely that the mixer will be a QSD due to the 20dB odd increase in NF from 2 to 30MHz that this mixer suffers from. 

I'm presently working on a replacement mixer, still using bus switches, that does not have this problem. Early results are very encouraging.  More details to follow.

73's  Phil..VK6APH 


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