Return-Path: X-Spam-DCC: paranoid 1002; 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=-2.0 required=5.0 tests=BAYES_00,DNS_FROM_AHBL_RHSBL, HTML_30_40,HTML_MESSAGE,SPF_PASS,UNPARSEABLE_RELAY 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 u8TGWRZx011272 for ; Thu, 29 Sep 2016 18:32:27 +0200 Received: from majordom by post.thorcom.com with local (Exim 4.14) id 1bpeCg-0004Et-HD for rs_out_1@blacksheep.org; Thu, 29 Sep 2016 17:28:58 +0100 Received: from [195.171.43.32] (helo=relay1.thorcom.net) by post.thorcom.com with esmtp (Exim 4.14) id 1bpeCd-0004Ek-0Z for rsgb_lf_group@blacksheep.org; Thu, 29 Sep 2016 17:28:55 +0100 Received: from omr-m009e.mx.aol.com ([204.29.186.8]) by relay1.thorcom.net with esmtps (TLSv1:DHE-RSA-AES256-SHA:256) (Exim 4.87) (envelope-from ) id 1bpeCa-0006Nl-Lj for rsgb_lf_group@blacksheep.org; Thu, 29 Sep 2016 17:28:53 +0100 Received: from mtaomg-aac02.mx.aol.com (mtaomg-aac02.mx.aol.com [172.27.2.36]) by omr-m009e.mx.aol.com (Outbound Mail Relay) with ESMTP id AAC61380004E for ; Thu, 29 Sep 2016 12:28:49 -0400 (EDT) Received: from core-acb09d.mail.aol.com (core-acb09.mail.aol.com [172.27.24.9]) by mtaomg-aac02.mx.aol.com (OMAG/Core Interface) with ESMTP id 2B2063800008B for ; Thu, 29 Sep 2016 12:28:49 -0400 (EDT) Received: from 192.35.17.13 by webprd-m19.mail.aol.com (10.74.15.139) with HTTP (WebMailUI); Thu, 29 Sep 2016 12:28:48 -0400 Date: Thu, 29 Sep 2016 12:28:48 -0400 From: Markus Vester To: rsgb_lf_group@blacksheep.org Message-Id: <15776c6e48a-454b-4f41@webprd-m19.mail.aol.com> In-Reply-To: <924779203.20160929001259@mterrier.net> MIME-Version: 1.0 X-MB-Message-Source: WebUI X-MB-Message-Type: User X-Mailer: JAS STD X-Originating-IP: [192.35.17.13] x-aol-global-disposition: G DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=mx.aol.com; s=20150623; t=1475166529; bh=Bwp2jLjUQUQ3c0OLdQakXLTHD24yKCxKvUr/jhjSKe8=; h=From:To:Subject:Message-Id:Date:MIME-Version:Content-Type; b=EKTAl9nHQawzbvFh4xwcN/OmGFyFQziSYSq0gQdNnWTM1hXoz4J0AS3cal3mL7BIc yfEYrpAMe4oTWooe1kXYuPJs4ORblTL0Q0Xy5j0qXQkrIh42tkPY8sP3zmIeOZkNV3 eE/vk7cT2B7ifJCXj9F/7Aj4F7J34Qww+RlMZLpY= x-aol-sid: 3039ac1b022457ed4141468d X-Scan-Signature: 91e1efbff209cbddb14bc9e018c2cfe8 Subject: Re: LF: F5WK EbNaut Content-Type: multipart/alternative; boundary="----=_Part_25753_1214436453.1475166528648" 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 10.1.3.11 Status: O X-Status: X-Keywords: X-UID: 8874 ------=_Part_25753_1214436453.1475166528648 Content-Type: text/plain; charset=utf-8 Content-Transfer-Encoding: quoted-printable Hi Michel, after I realized that the time offset was now 3 seconds I got a few more de= codes. Apparently SNR and condx were a bit weaker than the night before. 2016-09-28 "F5WK IN99EF" start symbol carrier df UT EbN0 EbN0 mHz 19:00:03 12.2 14.2 -1 19:30:03 14.7 17.9 -1 20:00:03 1.1 4.3 -1 20:30 (rx interruption) 21:00:03 12.7 14.7 0 21:30:03 13.5 16.6 -1 22:00:03 10.7 13.4 -1 Yes the undefined state of a divider before the PA can cause problems for c= oherent EbNaut (or Opera) transmissions. With the DDS, you could try to gra= dually advance the phase in 64 small steps to accumulate 360=C2=B0. Best 73, Markus -----Urspr=C3=BCngliche Mitteilung-----=20 Von: Michel Brunel An: rsgb_lf_group Verschickt: Do, 29 Sept 2016 12:14 am Betreff: Re: LF: F5WK EbNaut Hi Markus, Yes I'm still transmitting with the same ERP as the other days. The antenna is brought to resonance by a series loading coil and impedance= matching is performed by a tapped transformer. It seems to me that overcurrent applies only with an inductive mismatch, o= therwise it tends toward zero. This overcurrent is not noticeable at all, e= xcept that it triggers the ACS712 Hall effect sensor and the PIC A/D routin= e ! =20 Anyway the best approach is to use a DDS. I already tried that, but as my = class D PA requires 2*F, the phase offset should be 2*180=C2=B0 and as 360= =C2=B0 means 0=C2=B0, I thought that a immediate lower value - ie 174,375= =C2=B0 for the AD9851 - was not adequate. All the best, Michel - f5wk Le mercredi 28 septembre 2016 =C3=A0 23:21:50, Markus =C3=A9crivait : =20 Hi Michel, your signal is not weak at all, surely good enough for comfortable QRSS3 r= eading here.=20 Regarding overcurrent trip: I found that for safest operation of a class-D= PA, the antenna impedance should be presented as a series resonant circuit= to the transistors, because that will have high impedance for any out-of-r= esonance spectral components. Then during phase reversals, the current will= experience a dip rather than a peak. The impedance condition depends on th= e total phase shift of the matching circuits and low pass filters, which sh= ould ideally be 0 or 180=C2=B0. However feeding into a 50-ohm loading coil = tap (or through certain PI- or T-filters) tends to have around 90=C2=B0, tr= ansforming series resonance into parallel resonance, and presenting a short= -circuit to the PA for out-of-band exciation. Tonight there seems to be a (somewhat weaker) trace on your QRG again, are = you still sending EbNaut? Best 73, Markus (DF6NM) -----Urspr=C3=BCngliche Mitteilung-----=20 Von: Michel Brunel An: Domenico IZ7SLZ Verschickt: Mi, 28 Sept 2016 7:13 pm Betreff: Re: LF: F5WK EbNaut Hi, Big thanks to Domenico, Markus and Stefan for their successful decoding of= my EbNaut transmissions. Ebnaut decoding is not an easy task especially with weak signal. I fear my GPSDO frequency was not as accurate than expected. I had the bad= idea to use a low cost GPS antenna wich performed not as good as the professional grade antenna I used for tests at home. Th= us some jitter and phase jumps depending on GPS constellation position. As a "proof of concept" I made Loran-C records during the day using the e= bnaut setup and results are sometime good sometime not so good. The transmitter overcurrent was randomly triggered by the phase reversal.= Bpsk modulation is performed synchronously by exclusive OR gates, between = the D flip-flop and the MOS drivers. Phase reversal is like changing the fr= equency for a very short time, which leads to a current pike due to the hig= h Q of the LF antenna. Decision was taken to bypass the overcurrent detecti= on. The good way to do bpsk modulation is with a suitable DDS such as AD9852.= =20 I found the antenna performs poorly at LF since the radials are burried in= a sandy soil, as time goes on. No big deal for ebnaut though. A lot of things to improve for my next LF campaign,=20 73, Michel - f5wk/P=20 -- ------=_Part_25753_1214436453.1475166528648 Content-Type: text/html; charset=utf-8 Content-Transfer-Encoding: quoted-printable
Hi Michel,

after I realized that th= e time offset was now 3 seconds I got a few more decodes. Apparently SNR an= d condx were a bit weaker than the night before.

2016-= 09-28  "F5WK IN99EF"

start    symb= ol carrier df
 UT       EbN0 &nb= sp; EbN0   mHz

19:00:03  12.2 &nbs= p; 14.2   -1
19:30:03  14.7   17.9   = -1
20:00:03   1.1    4.3   -1
20:3= 0    (rx interruption)
21:00:03  12.7   14= .7    0
21:30:03  13.5   16.6   = -1
22:00:03  10.7   13.4   -1

Best 73,
Markus



-----Urspr=C3= =BCngliche Mitteilung-----
Von: Michel Brunel <f5wk@mterrier.net>=
An: rsgb_lf_group <rsgb_lf_group@blacksheep.org>
Verschickt: D= o, 29 Sept 2016 12:14 am
Betreff: Re: LF: F5WK EbNaut

Hi Markus,

Yes I'm still transmitting with the same ERP as the other days.

The antenna is brought to resonance by a series loading coil and impedance = matching is performed by a tapped transformer.
It seems to me that overcurrent applies only with an inductive mismatch, ot= herwise it tends toward zero. This overcurrent is not noticeable at all, ex= cept that it triggers the ACS712 Hall effect sensor and the PIC A/D routine= !  
Anyway the best approach is to use a DDS. I already tried that, but as my c= lass D PA requires 2*F, the phase offset should be 2*180=C2=B0 and as 360= =C2=B0 means 0=C2=B0, I thought that a immediate lower value - ie 174,375= =C2=B0 for the AD9851 - was not adequate.

All the best,
Michel - f5wk

Le mercredi 28 septembre 2016 =C3=A0 23:21:50, Markus =C3=A9crivait :


 Hi Michel,

your signal is not weak at all, surely good enough for comfortable QRSS3 re= ading here. 

Regarding overcurrent trip: I found that for safest operation of a class-D = PA, the antenna impedance should be presented as a series resonant circuit = to the transistors, because that will have high impedance for any out-of-re= sonance spectral components. Then during phase reversals, the current will = experience a dip rather than a peak. The impedance condition depends on the= total phase shift of the matching circuits and low pass filters, which sho= uld ideally be 0 or 180=C2=B0. However feeding into a 50-ohm loading coil t= ap (or through certain PI- or T-filters) tends to have around 90=C2=B0, tra= nsforming series resonance into parallel resonance, and presenting a short-= circuit to the PA for out-of-band exciation.

Tonight there seems to be a (somewhat weaker) trace on your QRG again, are = you still sending EbNaut?

Best 73,
Markus (DF6NM)



-----Urspr=C3=BCngliche Mitteilung----- 
Von: Michel Brunel <f5wk@mterrier.n= et>
An: Domenico IZ7SLZ <rsg= b_lf_group@blacksheep.org>
Verschickt: Mi, 28 Sept 2016 7:13 pm
Betreff: Re: LF: F5WK EbNaut

Hi,

Big thanks to Domenico, Markus and Stefan for their successful decoding of = my EbNaut transmissions.
Ebnaut decoding is not an easy task especially with weak signal.

I fear my GPSDO frequency was not as accurate than expected. I had the bad = idea to use a low cost GPS antenna wich performed
not as good as the professional grade antenna I used for tests at home. Thu= s some jitter and phase jumps depending on GPS constellation position.
As a "proof of concept" I made Loran-C records during the day  using t= he ebnaut setup and results are sometime  good sometime not so good.
The transmitter overcurrent was randomly  triggered by the phase rever= sal. Bpsk modulation is performed synchronously by exclusive OR gates, betw= een the D flip-flop and the MOS drivers. Phase reversal is like changing th= e frequency for a very short time, which leads to a current pike due to the= high Q of the LF antenna. Decision was taken to bypass the overcurrent det= ection.
The good way to do bpsk modulation is with a suitable DDS such as AD9852.&n= bsp;

I found the antenna performs poorly at LF since the radials are burried in = a sandy soil, as time goes on. No big deal for ebnaut though.

A lot of things to improve for my next LF campaign, 

73,
Michel - f5wk/P 






-- = ;
------=_Part_25753_1214436453.1475166528648--