Return-Path: X-Spam-DCC: paranoid 1102; 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,SPF_PASS 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 u8TMkPBv012115 for ; Fri, 30 Sep 2016 00:46:25 +0200 Received: from majordom by post.thorcom.com with local (Exim 4.14) id 1bpjzX-0005lm-5u for rs_out_1@blacksheep.org; Thu, 29 Sep 2016 23:39:47 +0100 Received: from [195.171.43.32] (helo=relay1.thorcom.net) by post.thorcom.com with esmtp (Exim 4.14) id 1bpjzC-0005ld-AD for rsgb_lf_group@blacksheep.org; Thu, 29 Sep 2016 23:39:26 +0100 Received: from out03.smtpout.orange.fr ([193.252.22.212] helo=out.smtpout.orange.fr) by relay1.thorcom.net with esmtps (TLSv1:DHE-RSA-AES256-SHA:256) (Exim 4.87) (envelope-from ) id 1bpjzA-0007KF-9x for rsgb_lf_group@blacksheep.org; Thu, 29 Sep 2016 23:39:24 +0100 Received: from [10.34.163.36] ([80.12.38.27]) by mwinf5d52 with ME id pafE1t00M0b8hls03afGnR; Fri, 30 Sep 2016 00:39:18 +0200 X-ME-Helo: [10.34.163.36] X-ME-Date: Fri, 30 Sep 2016 00:39:18 +0200 X-ME-IP: 80.12.38.27 Date: Fri, 30 Sep 2016 00:39:13 +0200 From: Michel Brunel X-Priority: 3 (Normal) Message-ID: <1044464829.20160930003913@mterrier.net> To: rsgb_lf_group@blacksheep.org In-Reply-To: <15776c6e48a-454b-4f41@webprd-m19.mail.aol.com> References: <924779203.20160929001259@mterrier.net> <15776c6e48a-454b-4f41@webprd-m19.mail.aol.com> MIME-Version: 1.0 X-Scan-Signature: dbfcc27a21e9e888d454ffd0e5adf99c Subject: Re: LF: F5WK EbNaut Content-Type: multipart/alternative; boundary="----------02E1C901513A010C8" 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: RO X-Status: X-Keywords: X-UID: 8880 ------------02E1C901513A010C8 Content-Type: text/plain; charset=utf-8 Content-Transfer-Encoding: quoted-printable Hi Markus, Does this 3second time offset come from my side ? No intentional change to= blame ! Could be a glitch with the VK16E GPS receiver - used only for NMEA, not for= the GPSDO. 73, Michel - f5wk Le jeudi 29 septembre 2016 =C3=A0 18:28:48, Markus =C3=A9crivait : 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, 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= ! =20 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.=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-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-----=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. 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 the eb= naut 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 t= he D flip-flop and the MOS drivers. Phase reversal is like changing the fre= quency 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 detectio= n. 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 --=20 -- ------------02E1C901513A010C8 Content-Type: text/html; charset=utf-8 Content-Transfer-Encoding: quoted-printable Re: LF: F5WK EbNaut Hi  Markus,
Does this 3second time offset come from my side ?  No intentional chan= ge to blame !
Could be a glitch with the VK16E GPS receiver - used only for NMEA, not for= the GPSDO.

73,
Michel - f5wk

Le jeudi 29 septembre 2016 =C3=A0 18:28:48, Markus =C3=A9crivait :


 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----- 
Von: Michel Brunel <f5wk@mterrier.net>
An: rsgb_lf_group <rsgb_lf_group@blacksheep.org>
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, 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.net>
An: Domenico IZ7SLZ <rsgb_lf_group@blackshe= ep.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 







-= - 




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