[pskmail] Re: server on Rasp Pi or Beablebone Black

  • From: Pär Crusefalk <per@xxxxxxxxxxxx>
  • To: pskmail@xxxxxxxxxxxxx
  • Date: Fri, 29 Aug 2014 10:34:58 +0200

Hi Ian,

Good advice. I use a standard phone charger to power the raspberry and
those are not always quiet.
I'll see what I can put after the charger to reduce the hash even
further, the charger I am using now is better so it's not a huge problem
any more.

73, Per

Ian Bennett skrev 2014-08-29 10:14:
> Per,
>       Not sure where your noise is getting in however I find I need to 
> "choke" wall warts to within an
> inch of it's life :-)
>       My problem is getting RF into the DC supply and find toroids rescued 
> from UPS especially useful. I
> wind as many turns as I can of the DC output from the power supply around the 
> toroid. Not only does
> this keep the RF out, it also makes the installation very neat as the power 
> supply cables are now
> very short :-)
>       This procedure is standard for anything I use. Not sure if it is making 
> any difference but it makes
> me feel better :-P
> Ian
> On 29/08/14 18:01, Pär Crusefalk wrote:
>> Hi,
>> I did have the Pi run a minecraft server for the kids prior to making it run 
>> pskmail.
>> Minecraft can be quite demanding, it certainly is very demanding when many 
>> players are using the
>> server and so I overclocked it.
>> By looking at the blog entry about that I was quite happy to do some 
>> overclocking as it should be
>> perfectly fine to do so:
>> http://www.raspberrypi.org/introducing-turbo-mode-up-to-50-more-performance-for-free/
>> The raspberry will reduce the speed if it should get too hot, mine is not 
>> hot at all but I have
>> applied all the heat sinks that are available for it.
>> Yesterday I put a new PSU there that did not QRM as much as the old and 
>> decided to launch the server
>> again.
>> Sadly I can now not launch fldigi as it dies complaining it could not find 
>> /proc/cpuinfo. I
>> recompiled fldigi but had the same issue so something has happened to it. 
>> Perhaps some other upgrade
>> has affected it. I will try to get some time to make it work again this 
>> weekend. When I did have it
>> running it did not consume very much cpu, not even when doing PSKR.
>> 73, Per
>> sm0rwo
>> John Douyere skrev 2014-08-29 03:31:
>>> Hi Greg,
>>> I can't remember saying it was not powerful enough, just that the THOR 
>>> modes are more demanding
>>> that most of the other modes.
>>> If I remember well the discussion thread I was asking if the CPU load was 
>>> not too high on
>>> Raspberry PI as the OM could not decode PSKR modes. In the end the issue 
>>> was not with CPU load but
>>> a bug in the Fldigi PSKR code.
>>> The OM also reported that THOR modes could be decoded.
>>> Having just converted a few Fldigi modems into Android using not the Java 
>>> language but C++
>>> *natively *I have some reasonable idea of the capability of some of these 
>>> ARM CPUs without the
>>> Java overhead.
>>> For example a rather old HTC Desire phone can decode PSKR, THOR, OLIVIA, 
>>> MFSK and even MT63 2000L
>>> without problems. The CPU load does not exceed 50% which leaves enough room 
>>> for other processes.
>>> Looking at the results of benchmarks like the Whetstone Native (not Java) 
>>> benchmark results for
>>> Raspberry PI on the net I find values of 95 MFLOPS at 700Mhz CPU clock (the 
>>> default I understand)
>>> and 134 MFLOPS at 1000Mhz clock speed (over-clocked).
>>> Compare this to the results of 120 MFLOPS for my HTC desire mentioned above 
>>> and you can see that
>>> it is very comparable. So in my opinion it should work on a Raspberry PI, 
>>> ASSUMING that there no
>>> significant extra overheads introduced by the GUI side of Fldigi + O/S.
>>> I don't know what Per has done to make it work in terms of configuration 
>>> but I would suggest
>>> looking at the following:
>>> - Overclock the Raspberry PI to 800-900MHz (Do some research here as it 
>>> seems to be the maximum
>>> acceptable long term continuous running overclock limit).
>>> - In Fldigi:
>>> 1. Set the slow CPU option ON.
>>> 2. IN THOR modem disable filtering, soft-symbol and soft-bit decoding.
>>> 3. In Audio / Settings I would choose either Linear interpolator or Fastest 
>>> Sinc interpolator.
>>> - Finally and it can be important on some devices, run Fldigi minimized. 
>>> This reduces the GUI
>>> processing quite significantly regardless of the settings of the waterfall.
>>> Maybe Per can detail his configuration to make it work on the Raspberry PI.
>>> I believe the Banana PI with it dual core 1GHz ARM-V7 architecture 
>>> (including hardware floating
>>> point unit) should provide a much lower CPU load when running Fldigi and a 
>>> Pskmail server.
>>> Hope this helps,
>>> 73, John (VK2ETA)
>>> On Thu, Aug 28, 2014 at 2:01 AM, Greg <kb1ncj@xxxxxxxxx 
>>> <mailto:kb1ncj@xxxxxxxxx>> wrote:
>>>     Greetings Group,
>>>     I see people mention they are setting up servers with these new micro 
>>> devices.. I thought I
>>>     remember when I asked about this maybe a year ago, John (VK) I think 
>>> said that they were not
>>>     powerful enough especially with the THOR modes... Still true? I would 
>>> switch my server out
>>>     just to save on electric use.
>>>     Also my server was on boot stuck for a few weeks but back on now..
>>>     Greg
>>>     KB1NCJ

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