[Linrad] Re: MAP65-not-IQ display oddities and doesn't decode

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

Hi Jeff,

I was traveling last week, just now getting caught up on email.

As far as I can tell from your screen shot at 
http://picasaweb.google.com/wa1hco/EME#
your SoftRock/Linrad/MAP65 combination is running properly.

Linrad's frequency scales are intended to show the actual 
on-the-air frequency of a signal.

MAP65's frequency scales are intentionally offset by 1.270 
kHz to reflect the quasi-channelized nature of JT65 
operation using audio tones and SSB transceivers.  When 
someone says he transmits on, say 144.120, he means that his 
SSB transceiver's dial is set to 144.120.  JT65 signals 
start at 1270.46 Hz, the frequency of the sync tone, and go 
up from there.  The sync-tone of someone who says he's on 
144.120 will be found at 144.121270 MHz.

> ... Notice the following in the image...
> 
>     * QSO on 144.130 according to ping jockey (W7MEM)
>     * Linrad waterfall (not shown) shows EME signal on .131-.132 (USB
>       1KHz tones, etc)
>     * EME signal shows up on the MAP65 upper display between .129 and
>       .130 ???
>     * Green cursor on upper at .130
>     * Signals on lower display show at 250 Hz up from 0 Hz

Yes, I can see the EME signal in the waterfalls at 0155, 
0157, and 0159.

> The softrock has it's zero frequency output at .125 and that displays 
> correctly on the linrad waterfall.  zero frequency on the MAP65 display 
> shows up at .122.5.  The frequency box in linrad show 144.125, the 
> "freq" parameter in par_ssb_fg is [144.12495600000].

Something is not quite right here.  Have you entered 
anything in the MAP65 Setup->Options box labeled "Fcal" ?

> In addition to these oddities, MAP65 doesn't decode, even with signals 
> strong enough to hear by ear.  I thought maybe IQ got reversed but the 
> signal generator shows up on the right frequencies in linrad and about 
> right in MAP65.  The lower graph shows sync on the left and data tones 
> on the right, which matches what WSJT shows.

Data tones of a JT65 signal should be above the sync tone. 
Anyway, your screen dump clearly shows (from the shorthand 
messages "RRR" and "73" from W7MEM) that you do not have I 
and Q reversed.  Decoding will fail if your computer clock 
is not set correctly.  Decoding of strong terrestrial 
signals often fails, for a number of reasons.  The decoder 
is happiest with EME signals.

> One last bug report.  If I close the band and messages windows, the 
> command window show some errors with "tkinter" in them and the main 
> MAP65 window stops working... but the waterfall continues normally.

Don't close those windows.  Minimize them if you don't want 
them on screen.

> One more thing about this map65 waterfall screen shot.  The spectrum
> only goes from 100 to 155 when Joe's screen shot at
> http://www.physics.princeton.edu/pulsar/K1JT/MAP65_5.JPG
> show a full 96 KHz of bandwidth.  What's up with that???

Displayed bandwidth is a user-settable parameter.  You are 
evidently using Fmin=100 and Fmax=160; these are the MAP65 
default parameters because they are what I usually use for 
2m EME, where JT65 activity is mostly found between 144.100 
and 144.160.

	-- 73, Joe, K1JT

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