[hpsdr] multiple receivers - is it really necessary

[Mike Hamel]

Hi Graham,

I have a friend who has a knack for putting things bluntly, and when I
talk with him about the potential applications for networked
multilocation SDRs, he dryly says "ok, but is it really radio anymore?"  :-D

Thanks for the VLBI references. I will get a stepladder and check them
out (likely a bit above my head).

Regards,

Mike
wo1u

Graham / KE9H wrote:
> Mike:
> 
> There are techniques that do this, see
> 
> http://www.gpstime.com/
> 
> and read the "Timing for VLBI -2009"  presentation by Tom Clark (K3IO),
> and Rick Hambly (W2GPS).
> 
> They are time stamping radio astronomy signals to (sub) nanosecond
> accuracies
> and can ship recorded signals from western China back to the US, and then
> assemble and post process them into "Very Long Base Line" received signals,
> with an aperture equal to the diameter of the earth. Using GPSDOs as the
> discipline and sync for an accurate time base.
> 
> Just time stamping to several nanosecond accuracy is enough to recover
> phase
> information for HF signals.
> 
> So, if every member of the Austin Amateur Radio Club made his home station
> available to the club station as one element of a phased array antenna
> system
> during a contest...
> 
> Is it single operator or multi operator?
> 
> Is it limited to 1500 Watts transmit power per licensed location, or
> "just" 1500 Watts
> total for the entire networked "antenna."
> 
> What if members of this list, in different countries, did the same thing?
> 
> :-)
> 
> --- Graham / KE9H
> 
> ==
> Mike Hamel wrote:
>> At the risk of maybe dragging this thread too far from the intended
>> topic, I had been thinking that one of the possible "big picture"
>> capabilities of multiple SDR stations located within a few miles of each
>> other could be a scenario where they share streaming raw data over the
>> net in such a way as to create an effectively huge aperture antenna for
>> receiving DX.
>>
>> Packet timestamping, phase alignment and the consequences of net latency
>> would make it a bit off from "real-time" but it seems like it should be
>> possible with internet connected SDRs.
>>
>> Each idle SDR could give some BW for the "shared pool" of data to be
>> aggregated.
>>
>> I haven't a clue how this 'pie in the sky' could be implemented but it
>> seems like an eventual future capability.
>>
>> /$0.02
>>
>> Mike
>> WO1U
>>
>>   
> 
> 

 1249262485.0