Hi Steve,
As it turns out, the most likely number of incorrect bits in the 87-bit
> message+CRC block contained within incorrect codewords is 20.
After reading Don message I was just figuring out this number for the LDPC
code used by FT8 :-)
What Don probably misinterpreted is that Koopman's
> They all reduce the number of incorrect decodes by about a factor of
> 2^12=2048.
Obviously, I have a problem with basic arithmetic. I should have said
> 2^12=4096.
>
It looks almost the 1.6 factor Joe was speaking about :-)
73
Nico / IV3NWV
>
> the chance that the error pattern passes the CRC test, that's to say the
> probability that an error goes undetected, is just inversely propoprtional
> to 2^L where L is the CRC polynomial degree.
That's why when a system uses an ECC what really matters to counterfeat
> undetected errors is
Furthermore there is no need to improve a protocol just to cope with energy
limits when a really variable medium, as the ionosphere is in the HFs, is
the limit itself. Of course we could think to a new mode in which a 2-way
QSO between two antipodal points on earth would require 50 mWatts instead
e JA5AEA
>
>
>
> Sent from Mail <https://go.microsoft.com/fwlink/?LinkId=550986> for
> Windows 10
>
>
> --
> *From:* Nico Palermo
> *Sent:* Friday, August 31, 2018 7:04:31 AM
> *To:* WSJT software development
> *Subject:* Re: [wsjt-devel] WSJT-X 2.0
>
> Probably we can add more flexibility if some information will be passed
> over Internet, for instance free text messages and GRID, it will spare more
> bits toward sensitivity on the radio interface.
Ok, Igor, but then I would prefer to call the new modes "Weak Internet
Communications".
73
> Most applications of diversity reception are on the MF and low HF bands. I
> believe that most fading on these bands is selective fading, where signals
> traveling slightly different paths, the low-frequency equivalent of
> picket-fencing at VHF/UHF. It might be worth studying propagation on the
Take,
we can indeed agree that transmitting an hash key could be better than to
send a full call sign.
Anyway when you transmit an hash key you miss the possibility for receivers
to go back to the original information unless they decode a complete
sequence of messages.
With FT8 or with all the
Igor,
I think that the Vojager probes communication links still work without any
HLR/VLR database technique at a distance of more than 100 astronomical
units and nobody makes complaints.
Am I missing something I yet don't know?
73
Nico / IV3NWV
___
Congratulations to you and Rex, Charlie.
I guess that it has not been so easy to make such a remarkable EME, earth
limb to earth limb, 19116 km QRB QSO on 10 GHz.
Really pretty.
73
Nico / IV3NWV
Il giorno sab 27 ott 2018 alle ore 12:25 <
char...@sucklingfamily.free-online.co.uk> ha scritto:
>
ed in classic textbooks.
>
>
>
> Finally, I enjoyed the conversation with you and thank you very much.
>
>
>
> 73
>
>
>
> take
>
>
>
> de JA5AEA
>
>
>
> Sent from Mail <https://go.microsoft.com/fwlink/?LinkId=550986> for
> Windows
>
> if ((x[9]&0x80)==1)
> return;
> warning: bitwise comparison always evaluates to false
Nothing really important but I would have appreciated more a warning like
this:
warning: bitwise comparison always evaluates to false, therefore I will
refuse to compile this source code until you
> We could enable -Werror by default :)
>
That would be great indeed, Richard.
I must remind myself to do it always ;-)
73
Nico / IV3NWV
___
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wsjt-devel@lists.sourceforge.net
Some things can be done more efficiently if they are "vectorized" but not
all the algorithms
can be easily vectorized with the current technology and maybe that chess
games belong
to this case, I'm not expert about them.
For what concerns our case, there's a lot of things that we can do in order
The same CPU I'm using here, Frank.
Actually the cores are only 4. It's Intel Hyper Threading technology that
makes them appear as 8.
Anyway it's not bad. Exploiting the AVX instruction set and all of its
cores, the computing power of an i7-4770 amounts to about 0.11 TeraFLOPS,
that's to say
Hi Phil,
I don't know what Joe used in WSPR but, for instance, he told me that
he generated the sync sequence used in Q65 by means of direct optimization
of its autocorrelation function, not in an algebraic way, so that its
lateral peaks
were minimum only in a limited time shift interval.
I guess
/ IV3NWV
___
Il giorno dom 16 mag 2021 alle ore 23:36 Phil Karn ha
scritto:
> On 5/16/21 09:15, Nico Palermo wrote:
> > Hi Phil,
> >
> > I don't know what Joe used in WSPR but, for instance, he told me that
> > he generated the sync se
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