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=-0.2 required=5.0 tests=BAYES_00,DNS_FROM_AHBL_RHSBL, HTML_40_50,HTML_MESSAGE,RATWARE_GECKO_BUILD 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 t91HCN1B027155 for ; Thu, 1 Oct 2015 19:12:23 +0200 Received: from majordom by post.thorcom.com with local (Exim 4.14) id 1ZhhCR-00069E-3D for rs_out_1@blacksheep.org; Thu, 01 Oct 2015 17:59:19 +0100 Received: from [195.171.43.32] (helo=relay1.thorcom.net) by post.thorcom.com with esmtp (Exim 4.14) id 1ZhhCQ-000695-Mu for rsgb_lf_group@blacksheep.org; Thu, 01 Oct 2015 17:59:18 +0100 Received: from mail-wi0-f180.google.com ([209.85.212.180]) by relay1.thorcom.net with esmtps (TLSv1.2:ECDHE-RSA-AES128-GCM-SHA256:128) (Exim 4.86) (envelope-from ) id 1ZhhBM-0003uZ-KW for rsgb_lf_group@blacksheep.org; Thu, 01 Oct 2015 17:59:17 +0100 Received: by wicfx3 with SMTP id fx3so37640635wic.0 for ; Thu, 01 Oct 2015 09:57:53 -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=message-id:date:from:user-agent:mime-version:to:subject:references :in-reply-to:content-type; bh=wmhygmL+9iJ4LVHhYiMpiJhIFxWlFho5CjRjpcmcz5A=; b=Bcs1BLI53fEccxlmoJwACl4pmQJueAcU0DLwpMQDh2KcYVL13PwTl6AK2eLmuuypsr WRtECMievljMftyIoTvr8Czm3afQH5t40H2j1g+Uvqwc+WvdoC8FRwzqPXM3Z4LbpMCx ScscibaVv5TnajeNZSg6XS33MBxd3Nosd7I2L9nu7/Jx8MqoB/wa+EDVt7HG1EIOQuOI m3eR8fLK5iCZ6b0So+2+EsWv6y0hfWgglrDqrpHL4q/M2MIWAirWCxUWrPRfghF15QVJ USw94MYGzMY52/1GxK8Y42wMxaPAjCQPvDGqbaYMqnHH04bdaAZoMqNZWXD5VLi9y/RX /CPg== X-Received: by 10.194.235.6 with SMTP id ui6mr13635194wjc.92.1443718673600; Thu, 01 Oct 2015 09:57:53 -0700 (PDT) Received: from [192.168.0.7] (net-37-182-103-27.cust.vodafonedsl.it. [37.182.103.27]) by smtp.googlemail.com with ESMTPSA id p4sm4072899wia.15.2015.10.01.09.57.52 for (version=TLSv1 cipher=ECDHE-RSA-RC4-SHA bits=128/128); Thu, 01 Oct 2015 09:57:52 -0700 (PDT) Message-ID: <560D660F.2070405@gmail.com> Date: Thu, 01 Oct 2015 18:57:51 +0200 From: IZ7SLZ User-Agent: Mozilla/5.0 (Windows NT 5.1; rv:17.0) Gecko/20130620 Thunderbird/17.0.7 MIME-Version: 1.0 To: rsgb_lf_group@blacksheep.org References: <5601EC9F.2010607@gmail.com> <56059B48.80606@freenet.de> <56069AD1.4040303@abelian.org> <56091C59.5010205@tele2.se> <56093BBC.9090104@tele2.se> <560C75E4.9040503@gmail.com> <560D4360.9030102@posteo.de> In-Reply-To: <560D4360.9030102@posteo.de> X-Scan-Signature: 86a33fe05fd4c52b025518dbd249b8c0 Subject: Re: LF: Coherent BPSK on LF using EbNaut Content-Type: multipart/alternative; boundary="------------090009010508070104090001" 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: 4231 This is a multi-part message in MIME format. --------------090009010508070104090001 Content-Type: text/plain; charset=UTF-8; format=flowed Content-Transfer-Encoding: 7bit /*Hallo Stefan,*//* *//* *//*thank you very much for your message.*//* */ On 10/1/2015 4:29 PM, DK7FC wrote: > Hi Domenico, > > Thanks for your report. > I see you on my OPDS32 grabber, as you say. > > 2015-09-28 21:00:47 IZ7SLZ 1159km 137502.120Hz 1mHz -46.7dBOp 93% > 17.9dB > 2015-09-28 20:00:47 IZ7SLZ 1159km 137502.120Hz 2mHz -41.1dBOp 90% > 20.4dB > 2015-09-28 19:00:45 IZ7SLZ 1159km 137502.120Hz 5mHz -44.1dBOp 93% > 18.8dB > 2015-09-28 18:24:51 IZ7SLZ 1159km 137502.121Hz 2mHz -45.0dBOp 75% > 15.2dB > > Is 137502.120 Hz the frequency of your choice? /**/ /*YES. CONFIRM.*/ > If your TX and my RX is GPS locked (or tracked) then where does the 1 > mHz offset come from? /*No. My Tx is not yet fully GPS-Locked but it is steered by an OCXO. That's why i need to check the frequency and make a small correction as done in the above OP32 sequence . After correction QRG remains quite steady for some hours.*//* */ > Maybe a phase variation due to changing propagation? *The tests carried out so far show that the phase stability of the LF path is sufficient for transmissions of at least 20-30 mins. Of course, it is necessary to do many other tests ***with differents conditions (message and symbol lenght, QRB, hours, seasons,...) *in order to better understand the channel capability. There is an interesting result achieved on Sept 14, 2015 with some my transmission of 43 characters at 0.2 s (duration = 7 min 47 s) succesfully received by DF6NM. See: https://www.dropbox.com/s/kimklrv25sbmwiu/ebnaut_150914_results.zip?dl=0 * > Which offset is acceptable to avoid SNR losses in EbNaut (at a symbol > rate that allows a QSO (in one evening! ;-) )) ? /*Here i quote a Markus' observation regarding this question*//*: *//* *//*On LF, the frequency stability of the TX and RX local oscillators comes in as an additional variable. It is very important that these are known and stable to better than 1/message_duration (about a mHz for a 20 minute sequence), which requires either GPS locked oscillators, or a very good OCXO or Rubidium. To circumvent possible soundcard glitches on TX, it may actually be better to use a hardware oscillator (eg. a DDS on the final RF frequency). */ > 73, Stefan PS: Unfortunately not QRV on LF at the moment. I need to > find a new loading coil body because my glass coil fully broke during > maintenance attempts. Now i need something to come out with a stronger > signal because each modification on the system has to be an > improvement, by definition. So maybe i can come closer to 1W ERP then... /*OK. We wait the restoration of your coil hoping that you want to try coherent bpsk. Your signal will be very useful for TA EbNaut test.*/ /*All the best*//* *//* *//*Domenico / iz7slz*/* * --------------090009010508070104090001 Content-Type: text/html; charset=UTF-8 Content-Transfer-Encoding: 8bit

Hallo Stefan,

thank you very much for your message.

On 10/1/2015 4:29 PM, DK7FC wrote:
Hi Domenico,

Thanks for your report.
I see you on my OPDS32 grabber, as you say.

2015-09-28 21:00:47 IZ7SLZ  1159km 137502.120Hz   1mHz -46.7dBOp  93% 17.9dB
2015-09-28 20:00:47 IZ7SLZ  1159km 137502.120Hz   2mHz -41.1dBOp  90% 20.4dB
2015-09-28 19:00:45 IZ7SLZ  1159km 137502.120Hz   5mHz -44.1dBOp  93% 18.8dB
2015-09-28 18:24:51 IZ7SLZ  1159km 137502.121Hz   2mHz -45.0dBOp  75% 15.2dB

Is 137502.120 Hz the frequency of your choice?  
YES. CONFIRM.
If your TX and my RX is GPS locked (or tracked) then where does the 1 mHz offset come from?
No. My Tx is not yet fully GPS-Locked but it is steered by an OCXO. That's why i need to check the frequency and make a small correction as done in the above OP32 sequence . After correction QRG remains quite steady for some hours.

Maybe a phase variation due to changing propagation?
The tests carried out so far show that the phase stability of the LF path is sufficient for  transmissions of at least 20-30 mins. Of course, it is  necessary to do many other tests with differents conditions (message and symbol lenght, QRB, hours, seasons,...)  in order to better understand the channel capability.
There is an interesting result achieved on Sept 14, 2015 with some my transmission of 43 characters at 0.2 s (duration = 7 min 47 s)  succesfully received by DF6NM. See:
https://www.dropbox.com/s/kimklrv25sbmwiu/ebnaut_150914_results.zip?dl=0
Which offset is acceptable to avoid SNR losses in EbNaut (at a symbol rate that allows a QSO (in one evening! ;-) )) ?
Here i quote a Markus' observation regarding this question:

On LF, the frequency stability of the TX and RX local oscillators comes in as an additional variable. It is very important that these are known and stable to better than 1/message_duration (about a mHz for a 20 minute sequence), which requires either GPS locked oscillators, or a very good OCXO or Rubidium. To circumvent possible soundcard glitches on TX, it may actually be better to use a hardware oscillator (eg. a DDS on the final RF frequency).


73, Stefan   PS: Unfortunately not QRV on LF at the moment. I need to find a new loading coil body because my glass coil fully broke during maintenance attempts. Now i need something to come out with a stronger signal because each modification on the system has to be an improvement, by definition. So maybe i can come closer to 1W ERP then...

OK. We wait the restoration of your coil hoping that you want to try coherent bpsk. Your signal will be very useful for TA EbNaut test.

All the best

Domenico / iz7slz

--------------090009010508070104090001--