[hpsdr] cuSDR remote operation?

[Phil Harman]

Hi Aivars,

You have raised an interesting topic regarding remote operation of HPSDR
systems.

In fact I'm currently in the process of writing an article about just this
topic seeing that there a number of different SDR architectures appearing
-these are:

1. Do the minimal amount of processing in the SDR hardware and do the bulk
in the PC/Tablet

2. Do all the DSP and networking in the hardware and keep any processing
in the PC/Tablet to an absolute minimum.  That way the SDR hardware can
plug directly into the Internet.

3. Do the minimal amount of processing in the SDR hardware. Use a small,
low cost, single board computer (SBC) connected directly to the SDR
hardware that is dedicated to the SDR and networking i.e. an SDR Server. 
This also removes the bulk of the processing from the PC/Tablet.

Most HPSDR users are using option 1 at the moment and Jeremy's success
with the iPad of being able to 'drink from a fire hose' is an impressive
example of how well this can work!

An example of option 3 is the work that John Melton is doing in porting
ghpsdr to a Raspberry PI SBC.

Each of these options has pros and cons but they are simply just that -
different options.

My own interest is in option 3 since we can keep the cost, and complexity,
of the SDR hardware down and many members can contribute to the design and
development of an SDR Server.

There are some very small, high performance and low cost, Linux based SBCs
appearing on the market that will make ideal SDR Servers.  This option
gives us enormous flexibility into the future.

With an SDR Server, using a highly efficient process to compress the
receive audio becomes viable as does compressing the bandscope data. In
which case the data rate from the SDR Server will be substantially lower
than a direct connection to Metis or Hermes.

And FYI, cuSDR uses a Client-Server architecture (although presently both
reside on the same PC during the development phase) which will support
option 3.

73 Phil...VK6APH





> ***** High Performance Software Defined Radio Discussion List *****
>
> On Nov 26, 2012, at 8:45 AM, "Aivars Straupe" <yl2gvc at inbox.lv> wrote:
>
>> ***** High Performance Software Defined Radio Discussion List *****
>>
>>  Hello!
>> I've got a question about cuSDR remote operation. Is it possible to
>> organize that over internet? First, how to transfer sound? Second, which
>> ports are necessary to forward? And, is there any possibility to
>> minimize traffic? I found just one, switch from 192 to 48. That minimize
>> traffic to 600kb/s, but that is still a lot. Any suggestions?
>
> Remember that currently openHPSDR hardware doesn't route IP.  That means
> you have to be on the same network segment as the hardware.  This
> precludes "over the Internet operation."  The big sticking point is that
> the hardware needs to get a discovery packet from an IP address to wake it
> up and get it to recognize you.  This has to be done via broadcast, which
> means that it must be done on the local network somehow.
>
> Audio shouldn't be an issue.  It's generated on the computer side anyways.
>  It doesn't need to be really "transferred," it needs to be pushed out a
> local device rather than (or in addition to) the openHPSDR audio
> connector.  This is what's done on Heterodyne for iPad because the typical
> use case for those folks is not near the openHPSDR rig.
>
>>  73!!!
>>                                      Aivars.
>
> --
> Jeremy McDermond (NH6Z)
> Xenotropic Systems
> mcdermj at xenotropic.com
>
>
>
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