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[Linrad] Re: MAP65-not-IQ display oddities and doesn't decode
- Subject: [Linrad] Re: MAP65-not-IQ display oddities and doesn't decode
- From: Joe Taylor <Princeton.EDU; joe@xxxxxxxxxxxxxxxx>
- Date: Mon, 06 Apr 2009 12:25:47 -0400
I was traveling last week, just now getting caught up on email.
As far as I can tell from your screen shot at
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
> 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
-- 73, Joe, K1JT
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