DRM
Leif Asbrink
Out of curiosity I installed Dream on my Debian Linux system using
the instructions here:
http://drm.sourceforge.net/installationapt.html
In case you want to try this, just skip commands like this:
cvs -d :pserver:anon...@drm.cvs.sourceforge.net/cvsroot/drm login
(I can not type in the correct password so I can not log in.
Does not matter, one does not have to log in to get the desired files)
I also had some problem with the ". bootstrap" command. It requires
the libtools package but that package does not exist. It is part of
some other package. I do not know which one because I installed
several packages that might be involved.
There are not many DRM transmissions that I can find. For good
reasons it seems to me since the decoder does not work particularly
well when there is selective fading. I have been listening for a
while on BBC World Service (5870kHz). The signal was very strong,
with an RMS power 40 dB above the noise floor. The QSB in the total
power is small, only a couple of dB. It seems to me that the decoder
can not handle the rather rapid changes of the channel. I can see
in the "Impulse Response" that three rays reach me from BBC and that
their relative signal levels varies in a time scale in the order of
10 seconds.
Stations with small or slowly changing selective fading seem to
decode well, but most signals I can hear are not that good....
Since I have Dream under Linux on one computer and the Perseus HF
receiver on another computer running MS Windows I have to use
an audio cable to transfer the DRM signal between soundcards.
That does not always work so well. For details, look here:
http://www.sm5bsz.com/linuxdsp/usage/drm/loudsp_carrier.htm
73
Leif / SM5BSZ
AdB
> Since I have Dream under Linux on one computer and the Perseus HF
> receiver on another computer running MS Windows I have to use
> an audio cable to transfer the DRM signal between soundcards.
> That does not always work so well. For details, look here:
> http://www.sm5bsz.com/linuxdsp/usage/drm/loudsp_carrier.htm
Leif,
this has been copied from that page
-----------------------
>
> At 22.15, the window that allows hardware control for the Perseus was moved by about 100 pixels upwards. That caused
> something to go wrong, after that the output is no longer a narrowband signal. The problem is also visible on the
> Winrad screen. As long as Winrad has not been disturbed by other tasks for the PC, the DRM decoder works fine in the
> other computer via an audio cable.
-----------------------
To avoid what you observe (the disturbance of Winrad by some other tasks in the PC) try the following :
- In the Winrad screen, click on 'ShowOption', then on 'Show Status'
- In the small panel that will open, click on 'Lock'
- At this point push the Start button of Winrad, after choosing the DRM mode
Now things should be better,meaning that the fractional resampler has been disabled, and as a consequence the DreaM
program works much better.
I don't know which decoder you are using, I suggest this http://pdis.rnw.nl/norbert/inst_dream.exe
which will install DreaM 1.10.6
73 Alberto I2PHD