Return-Path: X-Spam-DCC: paranoid 1233; Body=2 Fuz1=2 Fuz2=2 X-Spam-Checker-Version: SpamAssassin 3.1.3 (2006-06-01) on lipkowski.org X-Spam-Level: X-Spam-Status: No, score=-2.4 required=5.0 tests=BAYES_00,DNS_FROM_AHBL_RHSBL, HTML_MESSAGE autolearn=no version=3.1.3 Received: from post.thorcom.com (post.thorcom.com [195.171.43.25]) by paranoid.lipkowski.org (8.13.7/8.13.7) with ESMTP id t8PGPVGg029405 for ; Fri, 25 Sep 2015 18:25:31 +0200 Received: from majordom by post.thorcom.com with local (Exim 4.14) id 1ZfVl5-0005G6-DP for rs_out_1@blacksheep.org; Fri, 25 Sep 2015 17:22:03 +0100 Received: from [195.171.43.32] (helo=relay1.thorcom.net) by post.thorcom.com with esmtp (Exim 4.14) id 1ZfVl4-0005Fx-MI for rsgb_lf_group@blacksheep.org; Fri, 25 Sep 2015 17:22:02 +0100 Received: from mail-wi0-f182.google.com ([209.85.212.182]) by relay1.thorcom.net with esmtps (TLSv1.2:ECDHE-RSA-AES128-GCM-SHA256:128) (Exim 4.86) (envelope-from ) id 1ZfVk7-0008PF-4o for rsgb_lf_group@blacksheep.org; Fri, 25 Sep 2015 17:22:01 +0100 Received: by wicge5 with SMTP id ge5so27801376wic.0 for ; Fri, 25 Sep 2015 09:20:50 -0700 (PDT) X-DKIM-Result: Domain=gmail.com Result=Good and Known Domain DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=gmail.com; s=20120113; h=mime-version:in-reply-to:references:date:message-id:subject:from:to :content-type; bh=fc4SBQY7fvzkmAZpT4ghbH3GKjledkTk+xeA9q2+kfM=; b=zxqJENNQEw5pkhDwCXgc0WJKpY2w68Y0Ba3QXxxrtGS2bA1w50Ll2h7aoswNpehoDR dbbCYV7lcEyKYreOEJixvA9YVEnSrt8pQtTlEFd9zBgXTyb857MhFf8GDP7lC5j6lWmP OIdqdgDjTKft4yJdVzr0ZNM9w5DJatUiBW6z9QgXTKzw3j0BM80A5sNw0KMZ9wBm/c1L C4/scYhi+3HjJxZKl5A3X8jYB1FfujuTT0RpDTZ5f4YVSnXKAXwlNnVZU+Dlh9go6Ci5 lUuGT7uwduLCrpVYI07/1H598VcFkStseZUifv644gic6R3w5xdAnVMr0Grz5dnfJzk8 U3FA== MIME-Version: 1.0 X-Received: by 10.180.188.169 with SMTP id gb9mr4702969wic.72.1443198050387; Fri, 25 Sep 2015 09:20:50 -0700 (PDT) Received: by 10.28.47.212 with HTTP; Fri, 25 Sep 2015 09:20:50 -0700 (PDT) In-Reply-To: References: <5601EC9F.2010607@gmail.com> Date: Fri, 25 Sep 2015 17:20:50 +0100 Message-ID: From: Andy Talbot To: rsgb_lf_group@blacksheep.org X-Scan-Signature: bf14357d5ee2e4a717b88d90ab36122c Subject: Re: LF: Coherent BPSK on LF using EbNaut Content-Type: multipart/alternative; boundary=001a11c26bb8224bfd052094bbdd X-SA-Exim-Scanned: Yes Sender: owner-rsgb_lf_group@blacksheep.org Precedence: bulk Reply-To: rsgb_lf_group@blacksheep.org X-Listname: rsgb_lf_group X-SA-Exim-Rcpt-To: rs_out_1@blacksheep.org X-SA-Exim-Scanned: No; SAEximRunCond expanded to false X-Scanned-By: MIMEDefang 2.56 on 10.1.3.10 Status: O X-Status: X-Keywords: X-UID: 4148 --001a11c26bb8224bfd052094bbdd Content-Type: text/plain; charset=UTF-8 That gives me an idea ... For some time I've been toying with the idea of writing a utility that reads audio in blocks based on UTC timings and saves to a .WAV file . It woudl form part of a long term plan for playing with writing data mode software, using a similar timing protocol to WSJT, ie blocks of data timed on the minute, or 30s or whatever. Using blocks like this makes the software an awful lot simpler to write than trying use real time, continuous streaming audio. I was originally just going to save the audio to a mono .wav, but it would be easy enough to filter, decimate and downconvert to baseband. That way would allow a standalone prog for receiving EbNaut instead of a custom setting in Spectrum Lab The idea of using a .WAV file for storing baseband IQ data has a certain appeal, and one I hadn't thought of, even though stereo I/Q is used in real time for all the Softrock-type SDRs out there.. Andy G4JNT On 25 September 2015 at 15:37, Domenico IZ7SLZ wrote: > Hello Andy, all > thanks for interesting at this test. > > Yes, Spectrum Lab is the right program to manage the audio from receiver > also in this case. The SL configuration used in LF_EbNaut experiment > basically is the same of the DF6NM OPDS setup downloadable at Markus' site: > > http://df6nm.bplaced.net/opera/opds.zip > > Markus, as usual, includes all informations necessary to do the proper > changes according to the hardware at disposal. > > In my setup, i used SL to do many things: calibrate the sample-rate, > manage the ptt at scheduled time, generate a precise tone to drive my SSB > exciter, create some screenshots of the waterfall and - most important - > export, every 10 minutes, the FFT raw data of the reception periods. > > Markus will explain better than me this matter, but exporting FFT instead > of .WAV file seems a good solution to avoid some issues encountered with > the .wav recording function of SL. > He wrote a program (named ebnaut_ifft2.exe) able to convert FFT raw > data to wav file, inserting the appropriate timestamp. > > After this conversion, Ebnaut-rx can be used, but it needs of some - very > sensitive - offset entry. For that, you need to become skilled with the > use of some other Markus' tools that plot the symbol phase before the full > EbNaut-rx search. > > But, if the clock and the frequency have very small drift in both TX and > RX sides, than you can use the same measured parameters to catch the next > transmitted messages. > > 73, Domenico (iz7slz) > > > On 25 September 2015 at 13:23, Andy Talbot wrote: > >> EbAnut is a new one here - I hadn't heard of it. After Googling I found >> the page and read up / downloaded the software. Unfortunately, I see it >> is not standalone, and requires Spectrum lab to act as the audio "front >> end" to take in the Received audio, downconvert to a baseband I/Q and store >> that as a .WAV file. So downloaded Spectrum lab and tying to wade through >> how to use that. >> >> Could you perhaps give a short cut simple explanation of how to set up >> Spectrum lab to do that - it looks to be a very complex bit of software to >> drive. >> the EbNaut Tx and Rx programmes, in contrast, look very simple to use and >> it would be goo dto get more people using sensitive coherent signalling >> such as this. >> >> Some years ago I proposed GPS / UTC seconds locked coherent signalling on >> LF, but didn't have the expertise to write the software - and certainly not >> to implement strong FEC ! >> >> Andy G4JNT >> >> >> On 23 September 2015 at 01:04, IZ7SLZ wrote: >> >>> Hello LF, >>> >>> I am pleased to report a successful "Coherent BPSK" QSO between DF6NM >>> and IZ7SLZ on LF using EbNaut program of Paul Nicholson. >>> QSO took place in the night between Friday 2015-09-18 and Saturday >>> 2015-09-19 . >>> >>> I think it was the first time that anyone tried this on 137 kHz ! >>> >>> Frequencies used were 137510.00 Hz (DF6NM) and 137502.12 (IZ7SLZ). >>> >>> We exchange messages of 16 characters in coherent BPSK with UT >>> synchronous symbols, using a symbol period of 1 second and 8K19A scheme >>> coding. >>> >>> Software used were the Windows' versions of EbNaut-TX and EbNaut-RX (tnx >>> to P. Nicholson: your software is working without problems!). >>> Also Spectrum Lab (tnx Wolf !) was used to export FFT data, in a similar >>> way of the Markus' OPDS setup. >>> Other programs, written by Markus, were used: one to convert FFT >>> exported data for the EbNaut entry and another to search for the best >>> frequency and time offsets. >>> >>> There was not much phase drift during the qso and in other test >>> transmissions, since we reach a good frequency stability at both ends >>> thanks to Rubidium Reference Oscillator (Markus side) and a good quality >>> OCXO from my side. >>> >>> You can see reported symbol / carrier EbN0 and also the messages >>> exchanged, in the attached screen-shots taken at both ends. >>> >>> We hope now to joint other stations that want to challenge the timing >>> and frequency accuracy, to have a QSO in LF close to the Shannon limit. >>> >>> Markus DF6NM, will report soon all particulars and his comments of the >>> experiment. Thanks in advance Markus! >>> >>> 73, Domenico (iz7slz) >>> >>> >>> >>> >> > --001a11c26bb8224bfd052094bbdd Content-Type: text/html; charset=UTF-8 Content-Transfer-Encoding: quoted-printable
That gives me an idea ...
For some time I've been = toying with the idea of writing =C2=A0a utility that reads audio in blocks = based on UTC timings and saves to a .WAV file . It woudl form part of a lon= g term plan for playing with writing data mode software, using a similar ti= ming protocol to WSJT, ie blocks of data timed on the minute, or 30s or wha= tever. =C2=A0 Using blocks like this makes the software an awful lot simple= r to write than trying use real time, continuous streaming audio.

I was originally just going to save the audio to a mono .wa= v, =C2=A0but it would be easy enough to filter, decimate and downconvert to= baseband.=C2=A0 That way would allow a standalone prog for receiving =C2= =A0EbNaut instead of a custom setting in Spectrum Lab
The idea of= using a .WAV file for storing baseband IQ data has a certain appeal, and o= ne I hadn't thought of, even though stereo I/Q is used in real time for= all the Softrock-type SDRs out there..

Andy =C2= =A0G4JNT

On 25 September 2015 at 15:37, Domenico IZ7SLZ <iz7slz.domenico= @gmail.com> wrote:
Hello Andy,=C2=A0 all
thanks for interesting at thi= s test.

Yes, Spectrum Lab is the right program to = manage the audio from receiver also in this case. The SL configuration used= in LF_EbNaut experiment basically is=C2=A0the=C2=A0same of the DF6NM OPDS = setup =C2=A0downloadable at Markus' site:


Markus, as usua= l, includes all informations necessary to do the proper changes according t= o the hardware at disposal.

In my setup, i used SL= to do many things: calibrate the sample-rate,=C2=A0 manage the ptt at sche= duled time,=C2=A0 generate a precise tone to drive my SSB exciter,=C2=A0 cr= eate some screenshots of the waterfall and - most important -=C2=A0 export,= every 10 minutes, =C2=A0the FFT raw data of the reception periods.

Markus will explain better than me this matter, but expor= ting FFT instead of .WAV file=C2=A0seems a good solution to avoid some issu= es encountered with the =C2=A0.wav=C2=A0 recording function of SL.
He wrote a program (named ebnaut_ifft2.exe) able to convert FFT raw data= =C2=A0=C2=A0to wav file, =C2=A0inserting the appropriate timestamp.

After this conversion, =C2=A0Ebnaut-rx can be used, but i= t needs of some - very sensitive - =C2=A0offset entry. For that, =C2=A0you = need to become skilled with the use of=C2=A0some other Markus' tools th= at plot the symbol=C2=A0phase before the full EbNaut-rx search.
= =C2=A0
But, if the=C2=A0clock =C2=A0and the =C2=A0frequency have = very small drift in both TX and RX sides, than you can use the same measure= d parameters=C2=A0to catch the next transmitted messages.

73, Domenico (iz7slz)


On 25 September 2015 at 13:23, Andy= Talbot <andy.g4jnt@gmail.com> wrote:
EbAnut is a new one here - I hadn'= t heard of it.=C2=A0=C2=A0 After Googling I found the page and read up / do= wnloaded the software.=C2=A0=C2=A0 Unfortunately, I see it is not standalon= e, and requires Spectrum lab to act as the audio "front end" to t= ake in the Received audio, downconvert to a baseband I/Q and store that as = a .WAV file.=C2=A0=C2=A0 So downloaded Spectrum lab and tying to wade throu= gh how to use that.

Could you perhaps give a short= cut simple explanation of how to set up Spectrum lab to do that - it looks= to be a very complex bit of software to drive.
the EbNaut Tx and= Rx programmes, in contrast, look very simple to use and it would be goo dt= o get more people using sensitive coherent signalling such as this.

Some years ago I proposed GPS / UTC seconds locked cohere= nt signalling on LF, but didn't have the expertise to write the softwar= e - and certainly not to implement strong FEC !

An= dy=C2=A0 G4JNT

On 23 September 2015 at 01:04, IZ7SLZ <iz7slz.domenico@gmail.com> wrote:
Hello = LF,

I am pleased to report a successful "Coherent BPSK" QSO between D= F6NM and IZ7SLZ on LF using EbNaut program of Paul Nicholson.
QSO took place in the night between Friday 2015-09-18 and Saturday 2015-09-= 19 .

I think it was the first time that anyone tried this on 137 kHz !

Frequencies used were 137510.00 Hz (DF6NM) and 137502.12 (IZ7SLZ).

We exchange messages of 16 characters in coherent BPSK with UT synchronous = symbols, using a symbol period of 1 second and 8K19A scheme coding.

Software used were the Windows' versions of EbNaut-TX and EbNaut-RX (tn= x to P. Nicholson: your software is working without problems!).
Also Spectrum Lab (tnx Wolf !) was used to export FFT data, in a similar wa= y of the Markus' OPDS setup.
Other programs,=C2=A0 written by Markus,=C2=A0 were used: one=C2=A0 to conv= ert FFT exported data for the EbNaut entry and another to search for the be= st frequency and time offsets.

There was not much phase drift during the qso and in other test transmissio= ns, since we reach a good frequency stability at both ends thanks to Rubidi= um Reference Oscillator (Markus side) and a good quality OCXO from my side.=

You can see reported symbol / carrier EbN0 and also the messages exchanged,= =C2=A0 in the attached screen-shots taken at both ends.

We hope now to joint other stations that want to challenge the timing and f= requency accuracy, to have a QSO in LF close to the Shannon limit.

Markus DF6NM, will report soon all particulars and his comments of the expe= riment. Thanks in advance Markus!

73, Domenico (iz7slz)






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