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 x07DlWPb007031 for ; Mon, 7 Jan 2019 14:47:33 +0100 Received: from majordom by post.thorcom.com with local (Exim 4.14) id 1ggV3L-0000aX-JM for rs_out_1@blacksheep.org; Mon, 07 Jan 2019 13:34:51 +0000 Received: from [195.171.43.32] (helo=relay1.thorcom.net) by post.thorcom.com with esmtp (Exim 4.14) id 1ggV2r-0000aK-Ei for rsgb_lf_group@blacksheep.org; Mon, 07 Jan 2019 13:34:21 +0000 Received: from rhcavuit03.kulnet.kuleuven.be ([2a02:2c40:0:c0::25:136]) by relay1.thorcom.net with esmtps (TLSv1.2:ECDHE-RSA-AES256-GCM-SHA384:256) (Exim 4.91_59-0488984) (envelope-from ) id 1ggV2o-0002bI-CR for rsgb_lf_group@blacksheep.org; Mon, 07 Jan 2019 13:34:20 +0000 X-KULeuven-Envelope-From: rik.strobbe@kuleuven.be X-KULeuven-Scanned: Found to be clean X-KULeuven-ID: 4021C12000B.A6965 X-KULeuven-Information: Katholieke Universiteit Leuven Received: from icts-p-smtps-1.cc.kuleuven.be (icts-p-smtps-1e.kulnet.kuleuven.be [134.58.240.33]) by rhcavuit03.kulnet.kuleuven.be (Postfix) with ESMTP id 4021C12000B for ; Mon, 7 Jan 2019 14:34:15 +0100 (CET) Received: from ICTS-S-EXMBX21.luna.kuleuven.be (icts-s-exmbx21.luna.kuleuven.be [10.112.11.56]) (using TLSv1.2 with cipher AES256-SHA (256/256 bits)) (No client certificate requested) by icts-p-smtps-1.cc.kuleuven.be (Postfix) with ESMTPS id 3628340B4; Mon, 7 Jan 2019 14:34:15 +0100 (CET) Received: from ICTS-S-EXMBX27.luna.kuleuven.be (10.112.11.62) by ICTS-S-EXMBX21.luna.kuleuven.be (10.112.11.56) with Microsoft SMTP Server (TLS) id 15.0.1395.4; Mon, 7 Jan 2019 14:34:15 +0100 Received: from ICTS-S-EXMBX27.luna.kuleuven.be ([fe80::291a:cc4f:6953:698a]) by ICTS-S-EXMBX27.luna.kuleuven.be ([fe80::291a:cc4f:6953:698a%25]) with mapi id 15.00.1395.000; Mon, 7 Jan 2019 14:34:15 +0100 X-Kuleuven: This mail passed the K.U.Leuven mailcluster From: Rik Strobbe To: "rsgb-lf-group@groups.io" CC: "rsgb_lf_group@blacksheep.org" Thread-Topic: [rsgb-lf-group] FW: JT9-5 Drift Thread-Index: AQHUpYt1wQO5xszDOUu6R2nNd3dssqWiBbNygAAIr86AAatnAIAAE/NQ Date: Mon, 7 Jan 2019 13:34:15 +0000 Message-ID: <1546868053120.21793@kuleuven.be> References: <1546771383530.99285@kuleuven.be> <1546771678305.41844@kuleuven.be>, In-Reply-To: Accept-Language: nl-BE, en-GB, en-US Content-Language: nl-BE X-MS-Has-Attach: X-MS-TNEF-Correlator: x-ms-exchange-transport-fromentityheader: Hosted x-originating-ip: [10.112.50.1] MIME-Version: 1.0 X-Spam-Score: -2.3 (--) 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 @@CONTACT_ADDRESS@@ for details. Content preview: Hello Andy, the drift is given as Hz/min, so for JT9-5 the drift can be as high as 1Hz over the (almost) 5 minute TX cycle. The decoder must somehow be able to correct the drift within certain limits. Content analysis details: (-2.3 points, 5.0 required) pts rule name description ---- ---------------------- -------------------------------------------------- -2.3 RCVD_IN_DNSWL_MED RBL: Sender listed at http://www.dnswl.org/, medium trust [2a02:2c40:0:c0:0:0:25:136 listed in] [list.dnswl.org] 0.0 T_SPF_PERMERROR SPF: test of record failed (permerror) 0.0 HTML_MESSAGE BODY: HTML included in message 0.0 HTML_FONT_LOW_CONTRAST BODY: HTML font color similar or identical to background X-Scan-Signature: 01689d080f7c72ae346b011e9b322bfa Subject: LF: Re: [rsgb-lf-group] FW: JT9-5 Drift Content-Type: multipart/alternative; boundary="_000_154686805312021793kuleuvenbe_" X-Spam-Checker-Version: SpamAssassin 2.63 (2004-01-11) on post.thorcom.com X-Spam-Level: X-Spam-Status: No, hits=0.9 required=5.0 tests=HTML_30_40,HTML_MESSAGE, HTML_TAG_EXISTS_TBODY,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_154686805312021793kuleuvenbe_ Content-Type: text/plain; charset="iso-8859-1" Content-Transfer-Encoding: quoted-printable Hello Andy, the drift is given as Hz/min, so for JT9-5 the drift can be as high as 1Hz = over the (almost) 5 minute TX cycle. The decoder must somehow be able to correct the drift within certain limits= . 73, Rik ON7YD - OR7T ________________________________ Van: rsgb-lf-group@groups.io namens Andy TALBOT <= andy.g4jnt@gmail.com> Verzonden: maandag 7 januari 2019 14:13 Aan: rsgb-lf-group@groups.io CC: rsgb_lf_group@blacksheep.org Onderwerp: Re: [rsgb-lf-group] FW: JT9-5 Drift The JT9-5 tone spacing is 0.29Hz, so those drift figures correspond roughly= to a bit less than one complete tone spacing in the transmission period. = Which makes intuitive sense. The error correction allows it to "lose" the = few symbols at the end where it has drifted too far, while those at the sta= rt are near enough to work normally. (Pure speculation) The soft decision process in the decoder algorithm will = base its metric on how far the received signal is away from where it ought = to be, so a tone that has drifted into an adjacent bin may still have a qu= ite strong weighting applied. BTW Rik, you still appear to be copying these posts to the now-dead Yahoo G= roup Andy www.g4jnt.com On Sun, 6 Jan 2019 at 10:48, Rik Strobbe > wrote: Dear all, Roger, VK4YB, asked me about JT9-5 frequency stability requirement. As this might be interesting for others too, my answer below. 73 & HNY Rik ON7YD - OR7T ________________________________ Van: Rik Strobbe Verzonden: zondag 6 januari 2019 11:43 Aan: Roger Crofts Onderwerp: Re: JT9-5 Drift Hello Roger, as JT9-2 and JT9-5 signals are resampled to JT9-1 to be decoded by WSJT dec= oder engine it all depends on the drift tolerance of that decoder. For JT9-2 the frequency stability must be 2.222 times better than for JT9-1= . For JT9-5 it must even be 5.926 be better. As I couldn't find any information about the required JT9-1 stability I did= some brief tests with JT9-5: - At -5 dB level a drift up to 0.35 Hz/min seems acceptable. - At -15 dB level it is 0.26 Hz/min. - At -25 dB level it is 0.24 Hz/min - At -30 dB level it is 0.22 Hz/min - At -34 dB level (more or less the JT95 limit) it is 0.20 Hz/min But as said this was just a brief test, these numbers should be handled wit= h some caution. Also keep in mind that this numbers represent the combined TX and RX drift = (according to Murphy TX and RX drift will always be opposite). If using a transverter the TX drift is the combined drift of the driver TX = and the transverter. Furthermore I assumed that the drift was linear over time, for frequency ju= mps it might be different. Another frequency instability source will be the ionosphere, but there is l= ittle we can do about that (but the more stable TX and RX the more room for= ionospheric instabilities). Based on the above I would suggest to aim for a LO stability of no worse th= an 0.1 Hz/min, 0.05 Hz/min would be even better for weak signal DX (and tha= t is what JT9-5 is all about). Tests over the past weeks have shown that JT9-5 works very well for 136 kHz= DX (N1BUG was copied by numberous EU stations). On 472 kHz K3MF has been reported in Europe (as far as I know by G0LUJ and = myself). 73, Rik ON7YD - OR7T [https://ipmcdn.avast.com/images/icons/icon-envelope-tick-green-avg-v1.png]= Virus-free. www.avg.com _._,_._,_ ________________________________ Groups.io Links: You receive all messages sent to this group. View/Reply Online (#8445) |= Reply To Group | Reply To Sender | Mute This Topic |= New Topic Your Subscription | Cont= act Group Owner | Unsubscribe [rik.strobbe@kule= uven.be] _._,_._,_ --_000_154686805312021793kuleuvenbe_ Content-Type: text/html; charset="iso-8859-1" Content-Transfer-Encoding: quoted-printable

Hello Andy,


the drift is given as Hz/min, so for JT9-5 the drift can be as high as 1= Hz over the (almost) 5 minute TX cycle.

The decoder must somehow be able to correct the drift within certai= n limits.


73, Rik  ON7YD - OR7T



Van: rsgb-lf-group@groups.i= o <rsgb-lf-group@groups.io> namens Andy TALBOT <andy.g4jnt@gmail.c= om>
Verzonden: maandag 7 januari 2019 14:13
Aan: rsgb-lf-group@groups.io
CC: rsgb_lf_group@blacksheep.org
Onderwerp: Re: [rsgb-lf-group] FW: JT9-5 Drift
 
The JT9-5 tone spacing is 0.29Hz, so those drift figures correspond roughly= to a bit less than one complete tone spacing in the transmission period.&n= bsp; Which makes intuitive sense.  The error correction allows it to &= quot;lose" the few symbols at the end where it has drifted too far, while those at the start are near enough to work norm= ally.

(Pure speculation) The soft decision process in the decoder algorithm will = base its metric on how far the received signal is away from where it ought = to be, so a tone  that has drifted into an adjacent bin may still have= a quite strong weighting applied. 

BTW Rik, you still appear to be copying these posts to the now-dead Yahoo G= roup

Andy


On Sun, 6 Jan 2019 at 10:48, Rik Strobbe <rik.strobbe@kuleuven.be> wrote:

Dear all,


Roger, VK4YB, asked me about JT9-5 frequency stability requirement.

As this might be interesting for others too, my answer below.


73 & HNY


Rik  ON7YD - OR7T


Van= : Rik Strobbe
Verzonden: zondag 6 januari 2019 11:43
Aan: Roger Crofts
Onderwerp: Re: JT9-5 Drift
 

Hello Roger,


as JT9-2 and JT9-5 signals are resampled to JT9-1 to be decoded by WSJT = decoder engine it all depends on the drift tolerance of that decoder.<= br>

For JT9-2 the frequency stability must be 2.222 times better than for JT= 9-1.

For JT9-5 it must even be 5.926 be better.

As I couldn't find any information about the required JT9-1 stabili= ty I did some brief tests with JT9-5:

- At -5 dB level a drift up to 0.35 Hz/min seems acceptab= le.

- At -15 dB level it is 0.26 Hz/min.

- At -25 dB level it is 0.24 Hz/min

- At -30 dB level it is 0.22 Hz/min

- At -34 dB level (more or less the JT95 limit) it is 0.20 Hz/min

But as said this was just a brief test, these numbers should be handled = with some caution.

Also keep in mind that this numbers represent the combined TX and RX dri= ft (according to Murphy TX and RX drift will always be opposite).

If using a transverter the TX drift is the combined drift of the driver = TX and the transverter.

Furthermore I assumed that the drift was linear over time, for frequency= jumps it might be different.

Another frequency instability source will be the ionosphere, but there i= s little we can do about that (but the more stable TX and RX the more room = for ionospheric instabilities).

Based on the above I would suggest to aim for a LO stability of no worse= than 0.1 Hz/min, 0.05 Hz/min would be even better for weak signal DX (and = that is what JT9-5 is all about).


Tests over the past weeks have shown that JT9-5 works very well for 136&= nbsp;kHz DX (N1BUG was copied by numberous EU stations).

On 472 kHz K3MF has been reported in Europe (as far as I know by G0= LUJ and myself).


73, Rik  ON7YD - OR7T


3D"" Virus-free. www.avg.com
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