[Linrad] Re: Linrad - MAP65 communication

[Leif Asbrink <sm5bsz.com; leif@xxxxxxxxxxxxxxxx>]

Hi Rein,

> Very happy to report that MAP65I-Q is now running here and
> well on single laptop!( Thinkpad T42 )
Good:-)

> Leif and some others will try to write a document on how to do the
> 2 computer setup.
Others, I can not do that. I do not know how MAP65 is listening.
Maybe it listens to the loopback and then it might be ok to
send to the IP address of the computer running MAP65.

> Core problem was, I did not know how to tell Linrad the IP address
> needed to drive the network card to talk from de Linrad computer
> to the MAP65 computer. Of course once you know it it is easy....
> the par_netsend_ip file creation.
Here is what Joe wrote two years ago:



My earlier problem with dropped multicast packets seems to 
be fixed in MAP65 v0.8.  However, when running the 
Linrad-MAP65 combination on two separate computers I still 
have some network-related problems.  Perhaps someone on this 
list who knows much more than I about networking can help.

My computer network looks like this:


         ADSL      10 Mb/s  --> Computer_A
DSL --> Modem --> Ethernet --> Computer_B
                   Hub            |
                            --> Computer_C

Three computers are connected to a 10 Mb/s Ethernet Hub. 
Computer_A is my XYL's machine.  Computer_B runs Windows 
2000 Pro, and Computer_C runs Linux (presently the Kubuntu 
6.06 distribution).  In addition to the connections of all 
three machines to the hub, a crossover cable makes a direct 
100 Mb/s connection between computers B and C.

The ethernet interfaces on B and C appear to be configured 
correctly.  On Linux they appear as eth0 and eth1 
(occasionally they boot up as eth0 and eth2, I don't know 
why???).  Connections to the Hub are assigned dynamic IP 
addresses; I assigned hard-coded addresses 192.168.10.12 and 
192.168.10.13 for the direct inter-machine connection
between B and C.

I can use the 100 Mb/s direct line for many purposes.  I can 
ping over it in either direction; I can ssh into Linux from 
  Windows; I can use Cygwin/X (as described above) to 
display Linux X programs on the Windows screen.

However, I cannot seem to persuade Windows 2000 Pro to 
accept multicast packets over the direct line.  When I run 
Linrad on computer C and MAP65 on B, the multicast traffic 
is always received over the slow line, through the Hub. 
This uses most of the 10 Mb/s link's bandwidth, and my wife 
can't read her email when I'm on the air.  This is NOT GOOD.

By default the multicast traffic generated by Computer_C 
goes to eth0.  I can use the Linux "route" command to 
explicitly tell the system to use eth0:

# route add -net 224.0.0.0 netmask 224.0.0.0 dev eth0

This works fine (but of course, still sends the heavy 
multicast traffic through the hub).  If I remove this 
routing instruction and instead enter

# route add -net 224.0.0.0 netmask 224.0.0.0 dev eth1

the multicast data are not received by MAP65 running on the 
other machine.

If I unplug the crossover cable from the Windows machine and 
instead plug it into a laptop running Win/XP, the laptop 
receives the multicast packets without a problem.

Thus, it would seem that the problem must be in my setup of 
the Win2k machine -- the one with two ethernet interfaces. 
Can anyone shed any light on this situation for me?

I would be very happy to receive more feedback from others 
who have been using the Linrad-MAP65 combination.  Are there 
problems that I may have overlooked, perhaps because MAP65 
has been designed with the peculiarities of my own station 
in mind?  Please share your experiences on this list.

	-- 73, Joe, K1JT

It seems we have nobody on this list who really knows networking.


> Now  even with the par_netsend_ip added in the linrad directory,
> I was using ver 3.06 all the time, it is still not working.
> 
> Is it perhaps, that one needs to SHARE the hard drives on the local
> network?
NO. Linrad sends to whatever address you ask for. That is internal
in the computer where Linrad resides. Modern computers may have
several network interfaces and Linrad may or may not send to them all.
It may be necessary to configure the Linrad computer to not route
the the address Linrad is sending to through any other network
interface than the fast one. My laptop does not work properly
unless I disconnect the Ethernet cable because I have a slow
switch on the Ethernet that causes Linrad to wait for packages
running through it. The WLAN is fast however and is connected to a 
fast part of my network. I can of course connect the laptop directly
to another computer and then there is no problem.

> With 2 network cards plus the Ip's set I can transfer files, etc
> from the shared parts of the hard drives of the 2 computers.
> 
> Linrad refuses though to transfer data or MAP65 does not see or
> gets them. ( Linrad in Netsend )
> 
> With the laptop:
> 
> The files used per MAP65-IQ from K1JT website, ( par_netsend_ip 
> is included in this file set , ip address = 127.1.1.0, loop IP )
I think this will work only on a single computer. You have to
specify the IP address of the MAP65 computer or possible some 
other address that is specified in MAP65.

> I am monitoring some Beacons on 28 MHz at the moment.
> 
> SDR I-Q box running via USD 2.0 on laptop
> Mode SSB
> 
> 
> CPU load = abt 31 % reported by Lnrad
> 
> Windows task manager ( CTRL ALt Del ) reports:
> 
> abt 10 % CPU use for MAP65 
> abt 300 MB Memory use for MAP65
> 
> abt 37% CPU for Linrad   ( SSB mode at abt 90 Khz sampling rate
> Abt 25 MB Memory use for Linrad.
> 
> I assume when actually wsjt65B signals are t be decoded,
> the MAP65 load will increase.
> 
> Changing over to MAP65 and loading the practice file, it appears
> that the program starts to work really 10's of seconds after
> the test file load started.
> 
> 
> Bottom lime is that from here it certainly appears that SDR65 I-Q installs and
> is working in no time. It is ready to go!
> 
> 
> Softrock vs SDR I_Q.
> 
> Doug and I have done in the past some comparison measurements for the SDR box
> versus one of my softocks. Softrock is runnung with Si570 LO, and has
> a pre-selector. We found the sensitivity on 28 Mhz of the softrock approx
> 10 dB better then the SDR I-Q. 
> Softrock with a un modified delta44 sound card ( the same numbers with
> Linrad in SSB mode, Winrad and SpectraVue.
> 
> I use a little portable softrock SDR here with the laptop and have to use 
> an external soundcard for the I/Q processing ( USB sound card )
> 
> Of course, SDR IQ receives 0-30 MHz in one sweep, Sofrock is narrow band,
> and would need a lot extra to have it cover 30 MHz of as one spectrum.
The SDR-IQ is limited to a bandwidth of maybe 170 kHz. It depends on
the computer and the operating system because USB is the bottleneck.
On my Pentium IV under Linux in terminal mode it runs up to 230 kHz.

When you see the full spectrum in SpectraVue, you only see about 1% of
the time with a correspondingly poor S/N (and no chance to decode any
signal.)

  73

 Leif

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