Hi Alan,
Yes finding FreeDV activity (especially in VK) can be a challenge,
hopefully this will change as FreeDV becomes more competitive with SSB.
Hams tend to like Windows. Here is a Windows build (all in one ZIP
file) from SVN:
http://rowetel.com/downloads/freedv_1.3_svn3603.zip
There will be official Windows releases (with installers) in a few days,
just waiting for some feedback from the test team.
There is also a QSO finder: http://qso.freedv.org/
Cheers,
David
On 15/05/18 17:17, Alan Beard wrote:
Hi all,
I've been listening and transmitting on 7177KHz LSB but hear
nobody.
14150 and 14153 both have interference here so I've occasionally tried
on 14236KHz but again nothing.
I've "asked" on VKLOGGER and AHRDF. It seems there's all but nobody
willing to compile the sourcecode and run it except Mark VK5QI and me.
http://ahrdf.net/ and http://www.vklogger.com/
Does this show, just how few hams have Linux expertise?
I have not switched on a Windoze box for months, no need.
Anyway, I'm looking forward to some on-air tests.
No 73 valves here, nearest here a 6BK4.
Alan VK2ZIW
On Mon, 7 May 2018 13:50:17 +0200, Helmut Oeller wrote
Hi Glen,
very interesting paper! Thanks for sharing the link. Yes, I agree
that a realible 'simulator' providing the real world of a HF channel
would be very helpful to compare communication modes. Man-made noise
caused by PLC or SMPS etc. is another challenge especially on HF
bands. Before I'll stop my laudation for the 'old' SSB another
example what advanced DSP algorithms can effect in bad man-made
noise enviroment:
https://www.dropbox.com/s/wt32pepaurnbvbq/W5WC_NB%2CSNB%2CNR2_OFF.mp3?dl=0
https://www.dropbox.com/s/tubqmidw4bor265/W5WC_NB%2CSNB%2CNR2_ON.mp3?dl=0
Hopefully nobody feels offended by my lanky posts, but after more
than 50 years with activity on the commercial side of communications
I think that I earned a ticket for my point of view.
73, Helmut, DC6NY
-----Ursprüngliche Nachricht-----
Von: glen english <g...@cortexrf.com.au>
Gesendet: Montag, 7. Mai 2018 01:42
An: freetel-codec2@lists.sourceforge.net
Betreff: Re: [Freetel-codec2] 700D vs SSB Comparison
Hi David
fair enough
here is some good and reasonable recent work by one of your own.....
http://search.ror.unisa.edu.au/record/UNISA_ALMA11140739050001831/media/digita
l/open/9916110811201831/12140739040001831/13140739030001831/pdf
Maybe build into freeDV some sort of recording to disk and FTP
upload to codec2 server....
On 7/05/2018 9:02 AM, David Rowe wrote:
The 700D waveform is designed for subset of those paths. As part of
the testing I'd like to crowd source some samples of where it works
and were it doesn't.
Long term - if the average SNR is there, a waveform can be designed to
pass DV over it. Eventually.
DV over HF is a tough problem, and every development consumes 1000's
of volunteer man-hours (mainly mine). So I'm taking a tractable path
through the problem.
Currently the focus is on low SNR HF channels. I'll make incremental
improvements from there, e.g. rarer HF paths, higher speech quality at
higher SNRs etc.
- David
On 07/05/18 07:45, glen english wrote:
SSB sometimes wins because the brain picks up the slack. like with a
0.5 second fade.
In my opinion, for HF paths, to be broadly useful , voice DV modes
need to pass an HF fading simulator, targeted at vertical incidence
work, and bear in mind, that the channel profiles are quite different
for Equatorial, Mid latitude and high latitude locations. And they
must have minimal conversational delay, , < 0.25 seconds.
take a look at
https://www.itu.int/dms_pubrec/itu-r/rec/f/R-REC-F.1487-0-200005-I!!PDF-
E.pdf
several languages :
https://www.itu.int/rec/R-REC-F.1487-0-200005-I/en
This article, is useful for its 127 excellent references,
https://link.springer.com/article/10.1007/s11235-017-0287-2#CR38
and has some excellent channel profile references .
From the DRM spec, Annex B Definition of channel profiles
Channel 6, path 4
delta delay : 6mS, path gain RMS = 0.0625, dopplershift : 3.6Hz,
dopper spread 7.2Hz
Some paths are worse than that .. especially vertical incidence paths
what have values almost triple the above numbers....
-------------------------------------------------------------------------
-----
Check out the vibrant tech community on one of the world's most
engaging tech sites, Slashdot.org! http://sdm.link/slashdot
_______________________________________________
Freetel-codec2 mailing list
Freetel-codec2@lists.sourceforge.net
https://lists.sourceforge.net/lists/listinfo/freetel-codec2
--------------------------------------------------------------------------
----
Check out the vibrant tech community on one of the world's most
engaging tech sites, Slashdot.org! http://sdm.link/slashdot
_______________________________________________
Freetel-codec2 mailing list
Freetel-codec2@lists.sourceforge.net
https://lists.sourceforge.net/lists/listinfo/freetel-codec2
----------------------------------------------------------------------------
--
Check out the vibrant tech community on one of the world's most
engaging tech sites, Slashdot.org! http://sdm.link/slashdot
_______________________________________________
Freetel-codec2 mailing list
Freetel-codec2@lists.sourceforge.net
https://lists.sourceforge.net/lists/listinfo/freetel-codec2
----------------------------------------------------------------------------
--
Check out the vibrant tech community on one of the world's most
engaging tech sites, Slashdot.org! http://sdm.link/slashdot
_______________________________________________
Freetel-codec2 mailing list
Freetel-codec2@lists.sourceforge.net
https://lists.sourceforge.net/lists/listinfo/freetel-codec2
Alan
Evil flourishes when good men do nothing.
Consider the Christmas child.
---------------------------------------------------------------------------
Alan Beard Unix Support Technician from 1984 to today
70 Wedmore Rd. Sun Solaris, AIX, HP/UX, Linux, SCO, MIPS
Emu Heights N.S.W. 2750 Routers, terminal servers, printers, terminals etc..
+61 2 47353013 (h) Support Programming, shell scripting, "C", assembler
0414 353013 (mobile) After uni, electronics tech
------------------------------------------------------------------------------
Check out the vibrant tech community on one of the world's most
engaging tech sites, Slashdot.org! http://sdm.link/slashdot
_______________________________________________
Freetel-codec2 mailing list
Freetel-codec2@lists.sourceforge.net
https://lists.sourceforge.net/lists/listinfo/freetel-codec2
------------------------------------------------------------------------------
Check out the vibrant tech community on one of the world's most
engaging tech sites, Slashdot.org! http://sdm.link/slashdot
_______________________________________________
Freetel-codec2 mailing list
Freetel-codec2@lists.sourceforge.net
https://lists.sourceforge.net/lists/listinfo/freetel-codec2
