Return-Path: Received: from mtain-df12.r1000.mx.aol.com (mtain-df12.r1000.mx.aol.com [172.29.64.224]) by air-df05.mail.aol.com (v126.13) with ESMTP id MAILINDF051-5ef24b5626c3ac; Tue, 19 Jan 2010 16:40:19 -0500 Received: from post.thorcom.com (post.thorcom.com [193.82.116.20]) by mtain-df12.r1000.mx.aol.com (Internet Inbound) with ESMTP id 8D60538000184; Tue, 19 Jan 2010 16:40:17 -0500 (EST) Received: from majordom by post.thorcom.com with local (Exim 4.14) id 1NXLn6-000430-Ry for rs_out_1@blacksheep.org; Tue, 19 Jan 2010 21:39:12 +0000 Received: from [193.82.116.32] (helo=relay1.thorcom.net) by post.thorcom.com with esmtp (Exim 4.14) id 1NXLn6-00042r-AO for rsgb_lf_group@blacksheep.org; Tue, 19 Jan 2010 21:39:12 +0000 Received: from mail-fx0-f217.google.com ([209.85.220.217]) by relay1.thorcom.net with esmtp (Exim 4.63) (envelope-from ) id 1NXLn3-0000Q9-V5 for rsgb_lf_group@blacksheep.org; Tue, 19 Jan 2010 21:39:12 +0000 Received: by fxm9 with SMTP id 9so3341891fxm.30 for ; Tue, 19 Jan 2010 13:39:03 -0800 (PST) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=googlemail.com; s=gamma; h=domainkey-signature:mime-version:received:in-reply-to:references :date:message-id:subject:from:to:content-type; bh=OdZYHWQwOeWBaW08ZHunzg/Ro3vWqGu3q6NBdxtcS+g=; b=IzBmYJgv9IDPrglfSUNdUBo8N3tO3WU/wgwQiUyKuaI9+av8ORM4cCEcCtSCQx/w2W smp3+hMSNdr5nWVdyMvo2CXpaCDfw7aun6jg0sLdUdO8LWv80DzTNb2prUSrJDAJ2Loq xsp/voPUrKl+ROeEku0T7ek+ioeAVdWkw/4gQ= DomainKey-Signature: a=rsa-sha1; c=nofws; d=googlemail.com; s=gamma; h=mime-version:in-reply-to:references:date:message-id:subject:from:to :content-type; b=mx2GSMsO8PlBfQmYDjauysbzmJwAwZCOySpa+WHBSCTIsQ1CGTC0Xjv1EpUWUO2FtD 9jF3XC0IsqWCW4B6Q9cUd1hUgcqXF+sXxQkqgjJwLTUD7pK0UblaTz8mlXtSrb0fpf+a eItOc2+cFngiqXrr5mBc2gnOHfm7D4JjVt1t0= MIME-Version: 1.0 Received: by 10.239.145.204 with SMTP id t12mr843852hba.142.1263937143191; Tue, 19 Jan 2010 13:39:03 -0800 (PST) In-Reply-To: <1f0624b91001191326j354e4656nb687daa51e39a4ec@mail.gmail.com> References: <1f0624b91001191129t17c11cf3r5f522774b474b499@mail.gmail.com> <4B5610D0.5010808@xs4all.nl> <1f0624b91001191236s7f38c98dj8effabf54eaf129e@mail.gmail.com> <1f0624b91001191326j354e4656nb687daa51e39a4ec@mail.gmail.com> Date: Tue, 19 Jan 2010 21:39:03 +0000 Message-ID: From: Andy Talbot To: rsgb_lf_group@blacksheep.org X-Karma: unknown: DomainKey-Status: good (testing) X-Spam-Score: 0.3 (/) X-Spam-Report: autolearn=disabled,HTML_MESSAGE=0.001,MAILTO_TO_SPAM_ADDR=0.276 Subject: Re: LF: 500 kHz WSJT JT4A Content-Type: multipart/alternative; boundary=001485f7d87c7038db047d8b4ce7 X-Spam-Checker-Version: SpamAssassin 2.63 (2004-01-11) on post.thorcom.com X-Spam-Level: * X-Spam-Status: No, hits=1.5 required=5.0 tests=HTML_20_30,HTML_MESSAGE, LINES_OF_YELLING,MAILTO_TO_SPAM_ADDR 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 x-aol-global-disposition: G x-aol-sid: 3039ac1d40e04b5626c13a1e X-AOL-IP: 193.82.116.20 X-Mailer: Unknown (No Version) --001485f7d87c7038db047d8b4ce7 Content-Type: text/plain; charset=ISO-8859-1 JT4 is based on the old 11025Hz sampling, which is badly supported by modern soundcards unlike WSPR which is based on 12kHz sampling. This has lead many an op to get poor decoding performance on otherwise strong signals WSJT does have a self calibration routine built in, and shows you the correction needed. If the sampling rate is in error, the correction factors come up highlighted in red, and you need to enter these values into the setup screen. Most modern cards implement 11025Hz as 11100Hz, which at the end of a 48 second transmission interval results in 0.33 seconds error. This is a substantial offset - more than one symbol at the 4.375Hz rate - and usually fails. The source coding details are the same as JT65, so the manual for that, where it describes valid message formats, also applies to JT4. You can encode two callsigns plus a four digit locator in the message structure, or other compressed message formats, but to get the full 6 digit locator as we need for microwaves pluss callsign forces plain text mode. Andy www.g4jnt.com 2010/1/19 Gary - G4WGT > Ko & Andy, > > Thanks Ko for further decodes. > > Andy, I thought there may be some restriction/limit. I will look at the pdf > for more info, thanks. > > I also believe someone is trying to reply but I am not decoding for some > reason. > > Cheers, > > Gary - G4WGT. > > > 2010/1/19 Andy Talbot > > In its plain text mode which you have used, it can cope with just 13 >> characters. See http://www.g4jnt.com/Coding/JT4_Coding_Process.pdf >> and the WSJT documantation >> >> Andy >> www.g4jnt.com >> >> 2010/1/19 Gary - G4WGT >> >> Hi Ko, >>> >>> Thanks for the decode, not bad a -10 db at one point. >>> >>> There must be a character limit on the Tx text box (Tx1) I have used as >>> there is more than you have decoded. I will try placing the same text into >>> the Tx6 box & see if it sends more or all. >>> >>> 73 >>> >>> Gary - G4WGT. >>> >>> >>> >>> 2010/1/19 Ko Versteeg >>> >>> Gary - G4WGT wrote: >>>> >>>>> Hi All, >>>>> >>>>> For a while tonight I am transmitting a beacon on 503.600 kHz. >>>>> >>>>> The mode of operation is WSJT JT4A, transmitting on even minutes. >>>>> >>>>> Only using 15 watts RF & ERP 100 mW. >>>>> >>>>> If anyone would like to try & decode the message, post the results on >>>>> LF & I will confirm correct or not as the case may be. >>>>> >>>>> Sorry, no prizes :-(( >>>>> >>>>> >>>>> >>>>> 73 >>>>> >>>>> Gary - G4WGT. >>>>> >>>> >>>> Hi Gary >>>> Just received: >>>> >>>> 200200 6 -11 0.1 -477 31 * TEST G4WGT IO 1 0 >>>> 200300 0 -33 5.1 -451 42 >>>> 200400 22 -10 0.1 -477 24 * TEST G4WGT IO 1 0 >>>> >>>> 73 Ko, NL9222 - JO22ke >>>> >>>> >>>> >>>> >>> >> > --001485f7d87c7038db047d8b4ce7 Content-Type: text/html; charset=ISO-8859-1 Content-Transfer-Encoding: quoted-printable
JT4 is based on the old 11025Hz sampling, which is badly supported by= modern soundcards unlike WSPR which is based on 12kHz sampling.=A0=A0 Thi= s has=A0lead many an op to get poor decoding performance on otherwise stro= ng signals
=A0
WSJT does have a self calibration routine built in, and shows you the= correction needed.=A0 If=A0the sampling rate is=A0in error, the correctio= n factors come up highlighted in red, and you need to enter these values= into the setup screen.
=A0
Most modern cards implement 11025Hz as 11100Hz, which at the end of= a 48 second transmission interval results in 0.33 seconds error.=A0 This= is a substantial offset=A0- more than one symbol at=A0the 4.375Hz rate -= =A0and usually fails.
=A0
The source coding details are the same as JT65, so the manual for tha= t, where it describes valid message formats, also applies to JT4.=A0=A0 Yo= u can encode=A0two callsigns=A0plus a=A0four digit locator in the message= structure, or other compressed message formats, but to get=A0the full 6= digit=A0locator as we need for microwaves pluss callsign=A0forces=A0=A0pl= ain text mode.
Andy
www.g4jnt.com

2010/1/19 Gary - G4WGT <g4wgt@tiscali.co.uk>
Ko & Andy,=20

Thanks Ko for further decodes.

Andy, I thought there may be some restriction/limit. I will look at= the pdf for more info, thanks.

I also believe someone is trying to reply but I am not decoding for= some reason.

Cheers,

Gary - G4WGT.


2010/1/19 Andy Talbot <andy.g4jnt@go= oglemail.com>=20

In its plain=A0text mode which you have used, it can cope with just= 13 characters.=A0=A0 See http://www.g4jnt.com/Coding/JT4_Coding_Pr= ocess.pdf=A0=A0 and the WSJT documantation
2010/1/19 Gary - G4WGT <g4wgt@tiscali.co.uk= >=20

Hi Ko,=20

Thanks for the decode, not bad a -10 db at one point.

There must be a character limit on the Tx text box (Tx1) I have used= as there is more than you have decoded. I will try placing the same text= into the Tx6 box & see if it sends more or all.

73

Gary - G4WGT.



2010/1/19 Ko Versteeg <nl9222@xs4all.nl&g= t;=20

Gary - G4WGT wrote:
Hi All,

For a while ton= ight I am transmitting a beacon on 503.600 kHz.

The mode of operati= on is WSJT JT4A, transmitting on even minutes.

Only using 15 watts RF & ERP 100 mW.

If anyone would like= to try & decode the message, post the results on LF & I will conf= irm correct or not as the case may be.

Sorry, no prizes :-((


73

Gary - G4WGT.

Hi GaryJust received:

200200 =A06 =A0-11 =A00.1 -477 31 * =A0 =A0 =A0TEST= G4WGT IO =A0 =A0 =A0 =A0 =A0 =A0 1 =A0 0
200300 =A00 =A0-33 =A05.1 -45= 1 42
200400 22 =A0-10 =A00.1 -477 24 * =A0 =A0 =A0TEST G4WGT IO =A0 =A0= =A0 =A0 =A0 =A0 1 =A0 0

73 Ko, NL9222 - JO22ke



<= br>



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