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[Linrad] Linrad and MAP65-IQ



Hi Guy and all,

VK2KU wrote:
> I am finally up and running MAP65-IQ with Linrad 3-02.

That's great!  I'm happy to hear of another success.  Please 
continue to report your findings.

> 3. The critical thing seems to be the Linrad priority setting.
> Previously I have always run Linrad with AboveNormal priority,
> but I forgot to include this when setting up Linrad 3-02.
> In Linrad Setup, at the question "Run with High Process Priority", I
> said YES - WRONG!!!!

Yes.  I reported this to Leif a week or so ago; he was 
somewhat skeptical (and also rather out of patience with the 
seemingly odd behavior of Windows, and the 
difficult-to-plumb depths of Microsoft documentation).  I 
sympathize.

However, at least for the Linrad-and-MAP65-IQ-on-Windows 
combination, I think we have determined what works best.

> When I subsequently set Linrad to run at AboveNormal priority, the
> High setting in the Setup overrode this. Linrad freezes with 
> the High priority setting.

The same behavior is observed here.

> 4. So went back into Setup (S), and answered NO to the high priority
> question.
> 
> 5. Right click the ShortCut to Linrad, Click Properties, and edit the
> Target:
> C:\WINDOWS\system32\cmd.exe /c START /AboveNormal YourPath\linrad.exe
> where YourPath is the full path to your linrad.exe file.
> This will start Linrad every time with AboveNormal priority.

A good solution.

> 6. Everything now works!

Voila!

> 7. Initial impression 1 is that some things don't decode that would
> under WSJT6 - not really sure about that yet.

I don't think you'll find this true in general.  Keep in 
mind that the wideband (60-90 kHz) decoding pass typically 
must deal with dozens (if not a hundred or more) birdies. 
It needs to sort these out and distinguish them from 
legitimate JT65 signals.  The threshold for this decision 
may be a little higher in MAP65 than in WSJT, so a few 
potential decodes may be lost and not appear in the 
"Messages" and "Band Map" windows.

At your selected "QSO frequency", however, things are done 
slightly differently -- more like in the narrow band WSJT 
algorithm.  There, especially if you have reduced "Tol" to 
100 Hz or less, you will get slightly higher sensitivity.

You can always double-click on a visible signal to force a 
decoding attempt with maximum sensitivity.

Some other decoding features in a Linrad+MAP65 system are 
decidedly better than those in WSJT.  The AFC, for example. 
    And, of course, Linrad's wideband noise blanker.

> 8. Initial impression 2: the narrow waterfall doesn't seem to feed
> continuously as in WSJT6.
> Am I missing something?
> This removes the ability to decode shorthand messages by eye before
> the end of the sequence, and to freeze on a weak trace before the
> decode.

You are not missing anything.  As described in the MAP65 
documentation at

http://physics.princeton.edu/pulsar/K1JT/MAP65_Quick_Start.txt

"6. The waterfalls do not (yet) scroll in real time. 
Rather, they are updated at the end of each minute when 
decoding takes place.  Real-time scrolling may be added in 
the future."

I have not added this feature, and have no present plans to 
do so.  In a Linrad/MAP65-IQ system, you have waterfalls all 
over the place!  Two in Linrad, two more in MAP65.  I use 
the high-resolution Linrad waterfall for visual decodes.

For those that have missed it: in MAP65-IQ r1089, you must 
enter a parameter "Fadd" on the Setup -> Options screen. 
The value of Fadd is 144000 minus 1000 times the MHz part of 
the frequency setting for the SDR-IQ.  Example: you set the 
SDR-IQ to 28.050, so 144000-28000 = 116000.  Sorry, I know 
this is clunky and inconvenient.  The next program release 
will be better.

	-- 73, Joe, K1JT

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