Hi all,
Overview:
I have a radio (Yaesu FT-450). This feeds audio to a USB audio dongle
(Behringer UCA202/Burr-Brown original)
Software will "read" from this audio source, look for 700D sync, start
recording, do the error correction on recorded
digital packets (write to file). When the input audio drops out, looses sync,
stop recording.
At this point we have a stream of digital data packets (not audio) that are
error corrected. ready for retransmission.
Then transmit in clear SSB voice "700D repeater by VK2ZIW" and then from the
file recorded above, transmit the data
via the ofdm modem.
Now the specifics:
The GUI application FreeDV can directly "listen" to the audio stream. It
doesn't look like any of the command line codec2-dev
utilities can. Thus we have to use "record" (or "arecord" in Fedora Linux) to
"get" the audio stream. That's OK.
Now to find a utility that will "ofdm" the stream and output the Codec2 data
stream, not the "listenable" audio.
I tried:
./build1/src/c2enc 700D ./wav/vk5qi.wav /tmp/test2.tst --bitsperchar
Only to find mode 700D is not in "c2enc".
I take a known off-air sample and try to get it to ofdm data:
cat /home/data/apps/Samples/ve9qrp_700d_int1_slow_snr2dB.wav |
./build1/src/ofdm_demod - - --ldpc --interleave 1 > /tmp/test2.xxx
Now to re-modem it to a wav file:
cat /tmp/test2.xxx | ./ofdm_mod - - --ldpc --interleave 1 > /tmp/test2.raw
On playing this file with FreeDV GUI it is better in that it is "corrected" and
sync and interlev is never lost.
I think I'm ready to write a Repeater script.Anybody have any thoughts?
BTW: My project is to "just build a digital repeater" and not to decode the
digital stream down to audio.
This will run on a Pi, a Banana Pi with a 120Gb SSD as "/" to save power over
a PC drawing 50W plus.
Notes/Corrections:
README_fdmdv.txt mentions "src/fdmdv.h" that is perhaps "src/fdmdv_api.h"
./cohpsk_ch Can't find slow fading file: ../../raw/slow_fading_samples.float
I havn't yet found a way to command line play a 700D "raw" file.This I'd like
for monitoring.
No 73 valves here, what about anMRFE6S9160?
Alan VK2ZIW
On Fri, 29 Jun 2018 06:44:16 +0930, David Rowe wrote
> Hi Alan,
>
> Sounds like a fine project for you to work on. Can you be specific
> about what sort of help you want?
>
> Thanks,
>
> David
>
> On 28/06/18 19:19, Alan Beard wrote:
> > Hi David,
> >
> > I'm revisiting my Parrot Repeater idea.
> >
> > I have my Pi (Banana Pi) next to my radio ready and connected.
> >
> > I want to receive FreeDV 700D on 7177 or 14153 KHz and record the
> > digital data, not the c2 decoded audio.
> >
> > Then after the input Rx looses sync, transmit my callsign in clear SSB
> > then transmit the ofdm data recorded above.
> >
> > Can you help me with the command line tools?
> >
> >
> > Alan VK2ZIW
> >
> >
> > On Wed, 27 Jun 2018 10:08:04 -0700, Don wrote
> >> IDEs have their uses but getting a diverse team to agree on one is
> > usually
> >> a hopeless case. For example, if its editor does not use the key
> > patterns
> >> my brain-finger interface has deeply trained, then it will be a hard
> >> sell.
> >>
> >> Any good IDE should be able to support a basic Makefile/gcc project
> >> if you want to use it (my definition of good :-) ).
> >>
> >> Don
> >>
> >> On Wed, Jun 27, 2018 at 11:36:00AM -0500, Steve wrote:
> >> > On Wed, Jun 27, 2018 at 2:14 AM Alan Beard
> > <bear...@unixservice.com.au> wrote:
> >> > >
> >> > > So would it be prudent to use their ARM development environment?
> >> >
> >> > I use an IDE I really like, and it is very useful, but it was a
> >> > learning curve that I wouldn't wish on anyone. Prudent is a strong
> >> > word, as I wouldn't call command-line development imprudent.
> >> >
> >> > If someone were to document building a development system, and maybe
> >> > providing an Image, it would go a long way toward adoption. That's why
> >> > people use the SVN, as it is there, and you can build on it without
> >> > visiting many web pages to figure out what is what.
> >> >
> >> > Steve
> >> >
> >> >
> > ------------------------------------------------------------------------------
> >
> >> > 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
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
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