Radio Digital Signal Processing program discussion, originally under Linux ()

w3sz | 12 Dec 21:03

Re: linrad setup error

Hi, Leif et al,

Knoppix Live DOES use a ramdisk.  I do not know how large this generally  
is, but I believe Knoppix does some calculations when installing to decide  
how big to make this.

I have uploaded a new version of the OSS version of the Linrad Knoppix  
Live CD to the website:

http://www.sm5bsz.com/w3sz/knoppixlink.htm

Interestingly [and unfortunately] with this version of the CD which uses  
Knoppix 3.8 and Linrad-01.34 and the latest OSS version, the soundcard  
selection routine in Linrad is unable to open 4 channels for input such as  
is necessary for two receive channels each with I/Q receive.  I did not  
have this problem with the prior CD and do not know why this has  
occurred.  It works OK for I/Q sampling of ONE receive channel.

I will check into this as time permits.

73,

Roger
W3SZ

On Mon, 12 Dec 2005 03:57:04 -0500, leif@...
<leif@...>  
wrote:

> Hi Alex,

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leif-NjylAwyOilXQT0dZR+AlfA@public.gmane.org | 12 Dec 09:57

Re: linrad setup error

Hi Alex,

> after a Sunday afternoon passed in download ISO's and check them I was able
> to make a good CD_live of W3SZ version of Linrad and now my PC load all OK.
> The new problem I found is that when I am in the S mode and the program ask
> the parameters, I tried the suggested or to change, but always I receive
> this message: "Speed far too slow. Try less demanding FFT! Press any key.
This means that the first fft runs too slowly.
This is because you have selected a too narrow bandwidth that causes
a too large size for the fft - but since you have a PIII this should not
happen easily. My guess is that you ask for too much memory which
causes swapping to the hard disk. Execution then becomes really slow.....

There is a parameter "Use mlockall to prevent swapping?" in the general
parameters setup. (You can change it in par_userint with a text editor)

To minimize memory requirements, deselect second fft and AFC.
Set minimum fft1 storage time and minimum baseband storage time.
Once Linrad starts you will get a message on screen that shows how
large data areas you allocate. 256MB should be plenty, but maybe
some other process is running that uses up memory or cpu time?
I do not know anything about the Knoppix live CD. Maybe it uses
a RAM disk?

73

Leif / SM5BSZ

> Accept...." I made a lot of test but I've always the same answer: I see the
> PC making calculations but at the end I have always this answer. Do I make

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