[hpsdr] Multiple RX issues

Bob Cowdery bob at bobcowdery.plus.com
Tue Oct 14 00:50:30 PDT 2014 

Hi Joe and Helmut,

Thank you for the detailed explanation. I've been out of the loop so
long that although I monitor the list I wasn't really absorbing much.
I'm quite happy to have 3 receivers at the moment, just wanted to know I
didn't have some strange fault on my system. Everything has moved on so
much with some amazing features I think it will take me some time to
catch up. I will be spending more time now and plodding on with my
simple software now that RX is working good I will be adding TX, then
building the rest of the kits I've had laying around for probably a
couple of years and maybe even get on the air with it in the foreseeable!

73 Bob G3UKB

On 14/10/2014 08:14, Helmut wrote:
> Hi Bob,
>
> Let me add to Joe’s fine clarifications: There exist some considerations to
> eliminate the bottleneck Atlas. Please see Phil’s VK6PH presentation
> regarding to Gen2 Hardware at
> http://video.openhpsdr.org/HRF2014/News+Future%201.2.mp4
> BTW amp linearization by pre-distortion is also possible with standard
> Atlas-based Mercury and Pennylane using the previous filters on Mercury, but
> not with PowerSDR yet. Alfred, HB9EPU, implemented a very effective
> algorithm in his own specific software environment which improves at least a
> 300W LDMOS amp up to more than -50dBc IMD.
>
> 73, Helmut, DC6NY
>
> -----Ursprüngliche Nachricht-----
> Von: Hpsdr [mailto:hpsdr-bounces at lists.openhpsdr.org] Im Auftrag von Joe
> Martin K5SO
> Gesendet: Montag, 13. Oktober 2014 23:22
> An: Bob Cowdery
> Cc: hpsdr at lists.openhpsdr.org
> Betreff: Re: [hpsdr] Multiple RX issues
>
> ***** High Performance Software Defined Radio Discussion List *****
>
> Hi Bob, 
>
> It’s been a while since I’ve looked at the issue with regard to the
> Atlas-based system, but I seem to recall that the reduction of the number of
> receivers on Mercury was mostly due to the inability of the Atlas bus to
> adequatley handle the data rates at the higher sampling rates and multiple
> receiver configurations everyone was seeking.  The reduction from four
> receivers in the Mercury firmware occurred at the same time that the new
> polyphase-filter receiver modules were implemented and the higher sampling
> rate options were implemented.  We did have a four receiver version of
> Mercury firmware, v3.2 I believe, but it was limited to 192ksps for sampling
> rate and did not have the numerous C&C selectable options that the current
> Mercury firmware provides.  
>
> To utilize the full potential of cuSDR (or dual Rx PowerSDR with PureSignal
> for that matter) it is necessary to use platforms other than the Atlas-based
> HPSDR radio, at least at the present time.  
>
> There was some effort a while back, I believe, to implement PureSignal for
> the Atlas-based rigs but it has not been successfully achieved to my
> knowledge.  The simple truth is that the high data rates that are required
> for multiple receivers (more than 3) are accommodated better with
> single-board platforms (Hermes, Angelia, Orion) because they do not have the
> speed issues that are associated with the Atlas bus.  cuSDR should work fine
> for you as long as you limit yourself to 3 receivers when running an
> Atlas-based system.  PowerSDR internally limits things to 2 receivers when
> the “HPSDR” hardware (Atlas-based system) is selected, I think; other
> hardware selections (non-Atlas-based selections) within PowerSDR permit
> automatic use of greater numbers of receivers, as for example, to support
> PureSignal, etc.  
>
> 73, Joe K5SO
>
> On Oct 13, 2014, at 2:49 PM, Bob Cowdery wrote:
>
>> Hi Joe,
>>
>> Well, that certainly explains it and why Rx4 is all zeros. I really 
>> hadn't appreciated that as I took the spec at face value and seeing 
>> CuSDR allowing 7 I thought it must be implemented. Is that a hardware 
>> limitation with Atlas do you know?
>>
>> 73, Bob G3UKB
>>
>> On 13/10/2014 21:34, Joe Martin K5SO wrote:
>>> Hi Bob,
>>>
>>> Mercury v3.4 implements a maximum of 3 receviers in the firmware.  
>>>
>>> Metis_v2.6, which I think you said you are using, allows for 4 receivers,
> in principle, but that does you no good on the Atlas-based system as Mercury
> firmware limits the max number of receivers to 3.  
>>> 73, Joe K5SO
>>>
>>> On Oct 13, 2014, at 2:18 PM, Bob Cowdery wrote:
>>>
>>>> ***** High Performance Software Defined Radio Discussion List *****
>>>>
>>>> Just confirmed that the I and Q data for RX4 is all zeros so that 
>>>> has to be coming out the hardware. Any ideas anyone?
>>>>
>>>> 73, Bob G3UKB
>>>>
>>>> On 13/10/2014 20:43, Bob Cowdery wrote:
>>>>> ***** High Performance Software Defined Radio Discussion List *****
>>>>>
>>>>> Hi Warren,
>>>>>
>>>>> Thanks for the input. I'm only running 48K and I set CuSDR to 48K 
>>>>> as well. I don't think its running out of steam. CPU is about 10% 
>>>>> with 4RX and network about 25%, but only goes up to 27% with 5 RX. 
>>>>> Still higher than I expected though.
>>>>>
>>>>> The strange thing is that with 4 RX, the first 3 still work 
>>>>> correctly and there are no dropped packets or sync errors. I've not 
>>>>> checked the actual data of the 4th RX yet but I'm assuming its all 
>>>>> very low numbers close to zero as there is no audio and panadapter 
>>>>> flat lines at the bottom on CuSDR.
>>>>>
>>>>> Just to see what happened I tried 6 and 7 receivers, still no 
>>>>> dropped packets, rubbish out the audio and usage 15% CPU 31% 
>>>>> network. I still think something is going funny in the firmware.
>>>>>
>>>>> 73, Bob G3UKB
>>>>>
>>>>>
>>>>> On 13/10/2014 19:57, Warren C. Pratt wrote:
>>>>>> ***** High Performance Software Defined Radio Discussion List 
>>>>>> *****
>>>>>>
>>>>>> Hi Bob,
>>>>>>
>>>>>> Perhaps your problem with sync errors when the 5th receiver is 
>>>>>> enabled is that the 100Mbit interface will not support five 
>>>>>> receivers at 384K.  IF you are trying that at 384K, you'll need to
> back down to 192K.
>>>>>> I'm not sure I understand exactly what you mean about "no data and 
>>>>>> thus no audio."  If you are running PowerSDR, it only generates 
>>>>>> audio for RX1 (and its sub-receiver) and for RX2.  RX3, RX4, and 
>>>>>> RX5 are used for things such as the stitched panadapter, 
>>>>>> PureSignal, and diversity reception.  I'm not familiar enough with 
>>>>>> cuSDR to comment there.
>>>>>>
>>>>>> Hope that helps.
>>>>>>
>>>>>> 73,
>>>>>> Warren  NR0V
>>>>>>
>>>>>> On 10/13/2014 11:52 AM, Bob Cowdery wrote:
>>>>>>> ***** High Performance Software Defined Radio Discussion List 
>>>>>>> *****
>>>>>>>
>>>>>>> Hi,
>>>>>>>
>>>>>>> I've been playing around with multiple receivers on some software 
>>>>>>> I'm writing and something strange is going on.
>>>>>>>
>>>>>>> I can direct audio from each receiver to different local output 
>>>>>>> devices left/right/both so I can hear what's going on on each RX. 
>>>>>>> Everything is fine up to 3 receivers, the 4th receiver gives no 
>>>>>>> data and thus no audio and the 5th starts giving sync errors i.e. 
>>>>>>> the 7f7f7f is not where it should be.
>>>>>>>
>>>>>>> I installed and ran up CuSDR32 and I get exactly the same result. 
>>>>>>> I can't hear what's going on but RX4 has no panadapter output and 
>>>>>>> RX5 continually flashes the sync indicator.
>>>>>>>
>>>>>>> I've not updated the hardware for a while, using Metis 2.6 and 
>>>>>>> Mercury 3.4. Anyone know if there are any known issues with these
> versions?
>>>>>>> Failing that is anybody getting receivers above 3 working with 
>>>>>>> those versions.
>>>>>>>
>>>>>>> Thanks for any help
>>>>>>>
>>>>>>> 73 Bob (G3UKB)
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