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[Linrad] Linrad and MAP65-IQ
- Subject: [Linrad] Linrad and MAP65-IQ
- From: Joe Taylor <Princeton.EDU; joe@xxxxxxxxxxxxxxxx>
- Date: Wed, 04 Mar 2009 09:26:12 -0500
Hi Guy and all,
> 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
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
> 5. Right click the ShortCut to Linrad, Click Properties, and edit the
> 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!
> 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
You are not missing anything. As described in the MAP65
"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
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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