First of all I want to thank Leif SM5BSZ and Joe K1JT for nice system
Linrad+Map65.During ARRL EME with Serge RX1AS we have worked using
MAP65 and liked it very much.Also I listen HF bands and can say it is
very good receiver with big dynamic range. I'm going to use WSE in
CQWW CW and there are questions:
is it possible to increase the speed of change frequence with keys -
right-left of keyboard(mode M)?
How use Linrad with CW SKIMMER in wide band?
 Next: recently I have set up Linrad with WSE,DELTA44(modern computer)
for Serge. When we used version lir03-08,we got big noise and RX A/D
SPEED ERROR on screen, also the difference of frequence 25 kHz between
input signal and Linrad screen and output signal. Sampling rate was 96
kHz,  24 bit. We tried 48 kHz, then the frequencies became equals, but
ERROR stay. We have set up the version lir03-06 and got good output
signal without extra noise and ERROR disappeared,but the difference
stay when run at 96 kHz.

Hi Alex,

Yes.

The F1 help on the main menu gives (maybe too cryptic) info.

Also the F1 help on the control box where you change the arrow mode
T,P,B willtell you the same.

Use '+' or '-' to change the step size.

I do not have CW skimmer so I do not know what it requires.

Presumably CW skimmer can run from a soundcard.
As a first test you might try two computers and use a cable
between them. You could set Linrad to generate a wide
bandwidth with a high sampling rate on the output soundcard.

When you found something that works I assume it should be possible
to use Virtual Audio Cable VAC to send audio directly from Linrad
to CW SKIMMER within a single computer.
In order to be able to listen simultaneously you could run
a second instance of Linrad as a network slave.

I am afraid there is a bug in Windows (all versions) that makes PCI
cards useless at high speed in computers where there are also
PCI Express slots.
http://www.sm5bsz.com/linuxdsp/run/snd-compat/snd-compat.htm

Another problem is Vista and Windows 7. To make them work properly
it will be necessary to use ASIO or some other interface that avoids
the audiodg.exe problem of Vista and 7.

Pierre, ON5GN, has written some code that will be incorporated
in Linrad-03-09. The new code will make Linrad work with Portaudio
and it will allow ASIO an all the other drivers that might be
installed on the system. It may be Linux and output only in 03-09
but with time both input and output under Windows as well as Linux
will allow the use of portaudio. I do not expect that to solve
the Windows bug on modern computers with PCI plus PCI express.
That would have to be done by Windows Update.

The error you report for 03-08 is new to me.
Please make a screen dump so I can see what the
screen looks like. Before that, press 'T' so timing information
will be visible on the screen. Also run task manager so I can see
cpu and memory usage. In case the task manager hides part of the
linrad screen, make a second dump without it.
Then pack all your parameter files in a zip archive and send
the files to me off list. I will try to reproduce the error.

73

Leif / SM5BSZ

Hi Leif,
thank you for the quick reply.
I don't understand that,as don't know how to set Linrad to generate
wide banwidth.In this case it possible to use the output second
soundcard in first computer with Linrad.
I can do it ,when I meet Serge.
73,Alex,RU1AA

Hi Alex,

The reason Linrad is so complicated, to newcomers is that you
have a lot of fredom to select what processing you want.

First, get an understanding of the block diagram.
http://www.sm5bsz.com/linuxdsp/linroot.htm

The "first mixer bandwidth reduction" sets the sampling speed
of timf3 to a power of two less than the sampling speed at
your input. The bandwidth is 50% of the timf3 sampling rate.

Then you would have to select CW or SSB, and the widest possible
passband. That would prevent any further reduction of the sampling
speed. The BFO has to be placed outside the passband and the
output sampling speed has to be set well above two times the
bandwidth you have selected.

Select a small size for fft3 and do the filtering in the time
domain (there will be no decimation in this case.)

Just start with Linrad as a conventional SSB receiver that provides
another computer with audio from the soundcard. That should work
directly and involves no complications. Then you can start changing
parameters in small steps and watch the CW skimmer screen to
see what happens.

???????

If you want about 40 kHz bandwidth you would have to set the soundcard
to 96 kHz and it might be better to use the Delta 44.

Note that the solution is not ideal. Linrad does not have an
audio I/Q output because there has not been any need for that before
that I have been aware of.

When the portaudio interface is completed it will be possible
to cascade Linrad with Linrad through Jack and then I might find
it easy to add an I/Q output that would fit to any software
that can read data from a soundcard.

73

Leif / SM5BSZ