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[Linrad] Re: RX overrun error

Hello Joe and all,

Thanks for your reply. You ask if RX level that MAP65 shows is close to 0, no it is not. It is very high, about 65 dB.

Is this the problem?

73 Jan

On Thu, Aug 27, 2009 at 3:16 PM, Joe Taylor <
Hi Jan and all,

I know of no reason that Linrad and MAP65 should not be able
to run on the computers you are using -- or even both
programs on one PC.  MAP65 runs fine on multi-core or
multi-CPU machines.  It was developed on a dual-Xeon machine
and in my shack it always runs on a "Core 2 Duo" machine.
Many people are running both Linrad and MAP65 on one PC
(usually configured with two monitors).  This works fine, also.

> I have another problem. It is probably related to driver for LAN card. When
> I use N and T command to send out data to MAP65, sampling rate goes down and
> MAP65 cannot receive data. MAP65 is installed on an another PC. Checking
> network throughput; I assume that slightly more than 6 Mbps is requited for
> MAP65 (4x 96 kHz x 16 bits); I can see sometimes these 6 Mbps, but quite
> often less, even down to about 3 Mbps.

The crucial point is not what Windows Task Manager or some
other utility says about your network throughput.  It is
what MAP65 says.  The status-bar indicator on MAP65 should
never say "No Rx data" (with red background) during an Rx
minute, and the displayed counter of dropped packets should
read 0% or very close to 0%.  If these things are not true,
you have a problem with getting data into MAP65.

> One more issue with MAP65. Just running MAP65 without any incoming data, it
> seems to work well. When I am sending data via LAN, any try for decode ends
> with crash of MAP65. It is the same when 52nd seconds start automatic
> decode. Program freeze and the only way is to close it from program manager.
> Sometimes it closes itself.

Very clearly you have a problem.  None of these things
happen in a normally functioning Linrad-MAP65 system.

When you are receiving data from Linrad, is the "Rx noise"
reading somewhere close to 0 dB?

One of the reasons I now advise people to try Linrad and
MAP65 on one computer is that it eliminates the network as a
possible source of trouble.  Modern machines have plenty of
memory and CPU power for both programs.

> Changing program priority of both the Linrad and MAP65  has no effect.
> Overall CPU load is about 10 % for Linrad (Vista, dual 2 core @ 2.53 GHz, 4
> GB) and about 50 % on the second PC (XP, P IV @ 3 GHz, 2 GB) where MAP65 is
> running.

I very much doubt that program priority is your problem.  I
run everything at "normal" priority.  If your system runs
many other programs (most of them, probably, started
automatically at bootup, without your knowledge), it's hard
to say what problems might arise.  For precisely this
reason, I do not allow such things as virus-scanning
programs to run in my machines (unless I explicitly ask them
to run).

> One would expect that newer HW with high CPU power will work fine, it is not
> true at all. I tried to play with LAN card setting, buffer size etc. I am
> giving it one more week and then probably try to find some older PC for
> these application.

I have found no problems with very modern, powerful PCs.  If
you have Linrad configured so that it runs properly and
sends data to MAP65, your system should be perfectly able to
do what's wanted.

       -- 73, Joe, K1JT

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