Return-Path: Received: from post.thorcom.com (post.thorcom.com [195.171.43.25]) by klubnl.pl (8.14.4/8.14.4/Debian-8+deb8u2) with ESMTP id w2ODTopL011911 for ; Sat, 24 Mar 2018 14:29:52 +0100 Received: from majordom by post.thorcom.com with local (Exim 4.14) id 1ezj62-0004kt-FT for rs_out_1@blacksheep.org; Sat, 24 Mar 2018 13:20:34 +0000 Received: from [195.171.43.32] (helo=relay1.thorcom.net) by post.thorcom.com with esmtp (Exim 4.14) id 1ezj4T-0004kd-OF for rsgb_lf_group@blacksheep.org; Sat, 24 Mar 2018 13:18:57 +0000 Received: from gmy2-mh866.smtproutes.com ([94.186.192.195]) by relay1.thorcom.net with esmtp (Exim 4.89) (envelope-from ) id 1ezj4O-0005Ja-Vd for rsgb_lf_group@blacksheep.org; Sat, 24 Mar 2018 13:18:54 +0000 X-Katharion-ID: 1521897507.24449.gmy2-mh866 Received: from servigilant.vigilant.es ([85.60.35.36]) by gmy2-mh866.smtproutes.com [(94.186.192.195)] with ESMTP via TCP (TLSv1/TLS_DHE_RSA_WITH_AES_256_CBC_SHA); 24 Mar 2018 13:18:27 +0000 Received: from servigilant.vigilant.local ([fe80::c40d:8140:d722:5448]) by servigilant.vigilant.local ([fe80::c40d:8140:d722:5448%13]) with mapi id 14.03.0123.003; Sat, 24 Mar 2018 14:18:23 +0100 From: =?iso-8859-1?Q?VIGILANT_Luis_Fern=E1ndez?= To: "rsgb_lf_group@blacksheep.org" Thread-Topic: LF: K3RWR LF EbNaut in CT Thread-Index: AQHTwsxBoQ5mO9V3/kmcnGljZGvzyKPeCdqAgAAn7YCAABy8AIAAlZ+AgABwtf8= Date: Sat, 24 Mar 2018 13:18:22 +0000 Message-ID: <579355A36AEE9D4FA555C45D556003ABA3C3D00B@servigilant.vigilant.local> References: <16254e122f1-c8b-18d3d@webjas-vad169.srv.aolmail.net>,<5AB5F6A3.10109@posteo.de> In-Reply-To: <5AB5F6A3.10109@posteo.de> Accept-Language: es-ES, en-US Content-Language: es-ES X-MS-Has-Attach: X-MS-TNEF-Correlator: x-originating-ip: [144.178.133.70] MIME-Version: 1.0 X-Spam-Score: 0.0 (/) X-Spam-Report: Spam detection software, running on the system "relay1.thorcom.net", has NOT identified this incoming email as spam. The original message has been attached to this so you can view it or label similar future email. If you have any questions, see the administrator of that system for details. Content preview: Hi EbNauters I have an SL instance running but not surprise to get no decode here. Too much noise :( Anyway would be interesting to discuss the hardware needed for decoding EbNaut in LF Would help others to figure out how to start using their stations already decoding WSPR, etc [...] Content analysis details: (0.0 points, 5.0 required) pts rule name description ---- ---------------------- -------------------------------------------------- 0.0 HTML_MESSAGE BODY: HTML included in message X-Scan-Signature: 58ba09640deeac370be75328ed1b0fef Subject: Re: LF: K3RWR LF EbNaut in CT Content-Type: multipart/alternative; boundary="_000_579355A36AEE9D4FA555C45D556003ABA3C3D00Bservigilantvigi_" X-Spam-Checker-Version: SpamAssassin 2.63 (2004-01-11) on post.thorcom.com X-Spam-Level: X-Spam-Status: No, hits=0.5 required=5.0 tests=HTML_20_30,HTML_MESSAGE, TO_ADDRESS_EQ_REAL autolearn=no version=2.63 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 --_000_579355A36AEE9D4FA555C45D556003ABA3C3D00Bservigilantvigi_ Content-Type: text/plain; charset="iso-8859-1" Content-Transfer-Encoding: quoted-printable Hi EbNauters I have an SL instance running but not surprise to get no decode here. Too m= uch noise :( Anyway would be interesting to discuss the hardware needed for decoding EbN= aut in LF Would help others to figure out how to start using their stations already d= ecoding WSPR, etc I'm using Perseus SDR sampling 500KHz with SDR-Radio V2.3 from Simon Brown SDR-Radio can set up to six different VFO's in those 500KHz and send the au= dio of each one to different Virtual Audio channels. So it is like having 6 different recei= vers covering VLF, LF and MF There is one VFO at 136KHz demodulating USB at 4KHz wideband. This audio is= sent to a VAC channel to feed WSPR-2, Opera and two instances of Spectrum Lab, one for showing sp= ectrogram in my grabber and the new one for EbNaut to generate FFT files and then process with the = decoder First question: There is no sample rate correction here as I'm using virtua= l audio cable and not a hardware sound card. Is that a correct asumption ? So the only problem about frequency accuracy should be the SDR receiver clo= ck. Right ? SpectrumLab instance for EbNaut is getting the virtual cable audio channel = and doing a complex FFT with internal frequency shift at 1395Hz. As the dial frequency at SDR-Radio= is 136000Hz then we got the center frequency at 136000 + 1395 =3D 137395 Hz just at Rob= 's frequency The FFT decimation is 1024 and FFT lenght 131072 which produces Width of one FFT-bin: 328.571 uHz Equiv. noise bandwidth: 328.571 uHz Max freq range: 1.38423 kHz .. 1.40577 kHz FFT window time (length): 50.72 min The File Export of FFT is activated. So, a new file is created every 50.72 = min and contains 50.72 min of signal recorded. As transmission starts at 00 and 30 min past the hour, = every file should contain a complete message with enought margin to fit it Second question: Is that correct so far ? If an analog receiver is used (non SDR) then one should dial 136KHz USB and= route the audio to PC sound card I guess there would be two sources of frequency error that way. One would b= e the Rx own drift and precision and the other would be the soundcard sample rate error Sound card sample rate can be determined and compensated by SpectrumLab jus= t by injecting 1pps signal from GPS to the right channel of sound card (having signal in left channel). And for= the Rx drift and precision that depends a lot on the receiver technology as you already know I guess than Rx being stable enought, then you just need to determine your = Rx shift error and then can be adjusted later at decoding stage by configuring the decoder to watch for the signal = at the right place Please confirm if all this sounds phase coherent ;-) 73 de Luis EA5DOM --_000_579355A36AEE9D4FA555C45D556003ABA3C3D00Bservigilantvigi_ Content-Type: text/html; charset="iso-8859-1" Content-Transfer-Encoding: quoted-printable
Hi EbNauters

I have an SL instance running but not surprise to get no decode here. = Too much noise :(

Anyway would be interesting to discuss the hardware needed for decodin= g EbNaut in LF
Would help others to figure out how to start using their stations alre= ady decoding WSPR, etc

I'm using Perseus SDR sampling 500KHz with SDR-Radio V2.3 from Simon B= rown
SDR-Radio can set up to six different VFO's in those 500KHz and send t= he audio of each one
to different Virtual Audio channels. So it is like having 6 different = receivers covering VLF, LF and MF

There is one VFO at 136KHz demodulating USB at 4KHz wideband. This aud= io is sent to a VAC channel
to feed WSPR-2, Opera and two in= stances of Spectrum Lab, one for showing spectrogram in my grabber 
and the new one for EbNaut to generate FFT files and then process w= ith the decoder

First question: There is no sample rate correction here as I'm using v= irtual audio cable and not
a hardware sound card. Is that a correct asumption ?

So the only problem about frequency accuracy should be the SDR receive= r clock. Right ?

SpectrumLab instance for EbNaut is getting the virtual cable audio cha= nnel and doing a complex FFT
with internal frequency shift at 1395Hz. As the dial frequency at SDR-= Radio is 136000Hz
then we got the center frequency at 136000 + 1395 =3D 137395 Hz ju= st at Rob's frequency

The FFT decimation is 1024 and FFT lenght 131072 which produces
Width of one FFT-bin: 328.571 uHz
Equiv. noise bandwidth: 328.571 uHz
Max freq range: 1.38423 kHz .. 1.40577 kHz
FFT window time (length): 50.72 min

The File Export of FFT is activated. So, a new file is created every 5= 0.72 min and contains 50.72 min
of signal recorded. As transmiss= ion starts at 00 and 30 min past the hour, every file should contain=
a complete message with enought margi= n to fit it

Second question: Is that correct so far ?

If an analog receiver is used (non SDR) then one should dial 136KHz US= B and route the audio to PC sound card
I guess there would be two sources of= frequency error that way. One= would be the Rx own drift and precision 
and the other would be the soundcard = sample rate error

Sound card sample rate can be determi= ned and compensated by SpectrumLab just by injecting 1pps signal from GPS
to the right channel of sound card (h= aving signal in left channel). And for the Rx drift and precision that depe= nds a lot
on the receiver technology as you alr= eady know

I guess than Rx being stable enought,= then you just need to determine your Rx shift error and then can be adjust= ed
later at decoding stage by configuring the decoder to watch for the= signal at the right place

Please confirm if all this sounds pha= se coherent ;-)

73 de Luis
EA5DOM

 


--_000_579355A36AEE9D4FA555C45D556003ABA3C3D00Bservigilantvigi_--