[hpsdr] Hgx2

[Joe Martin K5SO]

Ken and All,

As it happens, polarization diversity is exactly my particular  
interest in using dual synchronized Mercury boards with both operating  
at the same frequency but with a bandwidth greater than 250 KHz  
preferably and each connected to a different polarization port on the  
antenna system!  Sorry, I don't follow the Linux reflector postings  
and so I don't know what you mean by the "M application" at all.   
Maybe it's exactly what I'm needing?

My thinking on the dual-Mercury-boards issue to date has been to learn  
how to code the FPGAs in both Mercury boards in order to extract the  
instantaneous (simultaneous) voltages at the two Mercury rf input  
jacks (one input for each orthogonal polarization port on the  
antenna), to square those voltage values, and then to add them  
together to form a single-output "power" level in order to achieve  
about a 3dB improvement in S/N over a single-polarity rf signal.

As I want to use this for pulsar star work I personally do not need  
the overhead of any communication demodulation schemes (e.g., to  
produce CW, SSB, FM, AM, etc signals) in the PC program.  I was  
thinking that the Ozy USB interface to the PC would be the appropriate  
path to take the power-level data into the PC for processing.  I'm not  
following you on how one might eliminate the Ozy interface function  
with the PC.  Certainly one could simply the PowerSDR program on the  
PC substantially but it seems to me that Ozy will still be a necessary  
component(?).  However, I'm certainly interested in knowing if there  
are other ways of collecting and processing such data.

For the present, I fully intend to re-write a version of the PowerSDR  
code to support the signal processing functionality that I described  
above so dealing with a PowerSDR-like program is not a terrible show  
stopper as I see it.

I'm sure others have very different reasons for wanting dual Mercury  
boards running though.  We can all benefit from exploring/discussing   
the various possible methods of doing it, I think.

Joe K5SO


On Feb 28, 2009, at 5:48 PM, Ken wrote:

> Joe - I am also interested  In the dual (synchronized) Mercury board  
> receiver (perhaps you have been watching the Linrad reflector).
>
>
>
> M application is polarization diversity for EME reception.
>
>
>
> Anyway, it would seem there are likely to be a number of ways to  
> attack this, it would be interesting to see discussion on the topic.
>
>
>
> For a simple single-frequency application (center frequency of the  
> pass band would be fixed) one could modify the FPGA program so that  
> OZY and PowerSDR are not needed. This would greatly reduce the  
> programming effort to get some proof of concept going.
>
>
>
> 73
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>
>
> Ken
>
>
>


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