[hpsdr] OZY II: USB vs Ethernet ?

[John Melton]

With the current broadband uplink/downlink speeds available it would not
be very feasible to send the I/Q data across the internet but it does
make a lot of sense across a home network.

The I/Q data for a single Mercury receiver running at 192K requires 9Mb
bandwidth (192000*3*2*8).  Running 8 concurrent receivers in Mercury at
192K requires 72Mb.

My 'up to 20Mb' broadband is running at about 6Mb downlink and 400Kb
uplink.  Doesn't stand a chance ;-)

However, it does make a lot of sense to perform the dsp work on a server
and just send the spectrum data and the audio stream to a client over
the internet.

You can see an example of this with my internet Mercury receiver at

     http://g0orx.homelinux.net/jmonitorapplet.html

The client is requesting the spectrum data 10 times per second and each
request if for 480 bytes.  The audio is converted to 8000 samples per
second and is sent as 8 bit uLaw.  So the total bandwidth required is
just 120kb (((480*10)+8000)*8).

-- John g0orx/n6lyt




On Sun, 2010-03-07 at 20:11 -0800, Curt, WE7U wrote:
> ***** High Performance Software Defined Radio Discussion List *****
> 
> On Mon, 8 Mar 2010, Phil Harman wrote:
> 
> > With the prototype OyzII I can attach it to my home network and access it
> > from any PC - that may be of interest to some folks.
> 
> Think bigger...  No reason to limit access to your home network.
> You could access it via Clearwire or cell-phone networking from a
> vehicle.  Access it from 802.11 access in a restaurant or clubhouse.
> Plug into a friend's network and access your home station.  Of
> course accessing it from a wireless laptop in/near my home would be
> fun too.
> 
> For Field Day:  Put the SDR radios near their antennas but widely
> separated from other radios.  Connect them all together with
> ethernet or 802.11.  Set up the tents wherever you like as they
> don't have to be near the radios or antennas.
> 
> Long-shot:  Might even interest people in creating/maintaining
> high-speed RF networking to access various SDR radios in the area.
> 



 1268036380.0