[hpsdr] cuSDR remote operation?

Sid Boyce g3vbv at blueyonder.co.uk
Mon Nov 26 19:47:17 PST 2012 

Hi guys,
I have been using the Raspberry Pi with the HiQSDR running 
ghpsdr3-alex's hiqsdr-server (480K samplerate) and dspserver.
It was running the raspbian distribution.

The only problem I experienced was getting audio from it locally using 
QtRadio.
On closing QtRadio as the waterfall and spectrum stopped I got great 
HDMI sound for between 20 seconds to a minute until the app finally died.

As a matter of fact even when playing any of the example sound files, 
the first word was always missing and the sound only came out of the 
HDMI monitor.
None of the supposed fixes could coax a whisper out of the on-board sound.

No problem accessing the server across the internet though.
73 ... Sid.

On 27/11/12 02:55, Lyle Johnson wrote:
> ***** High Performance Software Defined Radio Discussion List *****
>
> Phil,
>
> I agree, option 3 looks the best given the philosophy of the HPSDR 
> preoject, and the ability to leverage what has already been done.
>
> While a Raspberry Pi is an interesting widget, it seems to me that 
> there is little point in trying to use such a minimalist platform 
> except for the challenge of doing so.
>
> A project I am doing commercially uses an SBC from 
> www.embeddedarm.com  As you note, there are lots of choices in the 
> marketplace.  This is one piece of hardware we ought not to need to 
> develop ourselves!
>
> 73,
>
> Lyle KK7P
>
>> ***** High Performance Software Defined Radio Discussion List *****
>>
>> 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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>>>
>>
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>
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-- 
Sid Boyce ... Hamradio License G3VBV, Licensed Private Pilot
Emeritus IBM/Amdahl Mainframes and Sun/Fujitsu Servers Tech Support
Senior Staff Specialist, Cricket Coach
Microsoft Windows Free Zone - Linux used for all Computing Tasks


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