[linrad] Re: MAP65

[Joe Taylor <Princeton.EDU; joe@xxxxxxxxxxxxxxxx>]

Hi Francesco,

When I receive an email from "root", I always know that it 
comes from a Linrad user!

I hope you do not mind if I copy this reply to the Linrad 
reflector.  I think your question and my answer may be 
interesting to others.

root wrote:
> Hello Joe, a simple question.
> I use Linrad by long and long time, but 
> with only "H" pol antenna. My question is
> may i use MAP65?

Yes!

> And if the answer is positive, may i use it with results,
> on my Notebook with the AC97 soundblaster and without wire (cross cable)
> connection, right as i do today, where i have the main PC with Ubuntu
> and Linrad and the notebook with the wsjt. They are only connected via
> sound blaster.

As I understand it, you are connecting Linrad's audio output 
to audio input on the Notebook, using an audio cable.  WSJT 
runs on the Notebook, and gives you a bandwidth of something 
like 2-4 kHz, right?

This procedure will not work for MAP65, because MAP65 wants 
to have access to the full 90 kHz bandwidth available inside 
Linrad.  (I am assuming that your Linrad setup uses 96 kHz 
sampling, as I do.)

For your setup to work with MAP65 you can use one of these 
approaches:

1. Run both Linrad and MAP65 on the Linux computer.  This 
may be an attractive possibility if this computer is fast 
(say, 2.4 GHz or faster CPU) and has plenty of memory (at 
least 1 GB).  You will need two display screens -- and 
therefore either two video cards, a dual-monitor video card, 
or "remote display" of the MAP65 information to a second 
computer connected by ethernet.  You might also need as many 
as three sound cards: for example, a Delta44 for Linrad 
input, the motherboard AC97 for Linrad sound output 
(required only for human monitoring), and a cheap add-on 
card for sending the Tx audio from MAP65 to your transmitter.

2. Run Linrad in your Ubuntu Linux machine and MAP65 in the 
Windows Notebook.  This is probably simpler, and is 
certainly closer to what you have now.  The Linrad setup
stays as it is, but you enable its multicasting "network 
output" of 16-bit timf2 data .  The two computers must be 
connected to the same local area network, either through an 
ethernet switch or on a private RJ45-style crossover cable. 
 MAP65 receives its data input from the ethernet port, and 
sends Tx Audio to the transmitter.  You will want to have at 
least 1024 x 768 screen resolution on the Notebook.

> ciao and thank you in advance
>
> Francesco,IK2DDR

One additional point.  I solved the problem I was having, in 
which the Linrad --> MAP65 multicast data stream swamped my 
in-house LAN so that my wife could not read email on her 
computer.  I changed the code in Linrad so that instead of 
using "multicasting," it sends the UDP packets explicitly 
("unicast") to the IP address of my MAP65 computer.  Then 
they do not pass through the cheap ethernet switch to which 
the computers are connected, and Marietta is happy again 
because her part of the network is not swamped.

I will be happy to help more, if I can -- but you should 
know that I will be away on vacation (at the beach, with 
grandchildren) for the next three weeks.

	-- 73, Joe, K1JT

#############################################################
This message is sent to you because you are subscribed to
 the mailing list <linrad@xxxxxxxxxxxxxxxxxxxxx>.
To unsubscribe, E-mail to: <linrad-off@xxxxxxxxxxxxxxxxxxxxx>
To switch to the DIGEST mode, E-mail to <linrad-digest@xxxxxxxxxxxxxxxxxxxxx>
To switch to the INDEX mode, E-mail to <linrad-index@xxxxxxxxxxxxxxxxxxxxx>
Send administrative queries to  <linrad-request@xxxxxxxxxxxxxxxxxxxxx>


LINRADDARNIL