Return-Path: Received: from mtain-dg02.r1000.mx.aol.com (mtain-dg02.r1000.mx.aol.com [172.29.65.10]) by air-dc09.mail.aol.com (v126.13) with ESMTP id MAILINDC093-86554b5b6562280; Sat, 23 Jan 2010 16:08:50 -0500 Received: from post.thorcom.com (post.thorcom.com [193.82.116.20]) by mtain-dg02.r1000.mx.aol.com (Internet Inbound) with ESMTP id 2C7A1380000C8; Sat, 23 Jan 2010 16:08:48 -0500 (EST) Received: from majordom by post.thorcom.com with local (Exim 4.14) id 1NYnCt-0008KG-87 for rs_out_1@blacksheep.org; Sat, 23 Jan 2010 21:07:47 +0000 Received: from [83.244.159.144] (helo=relay3.thorcom.net) by post.thorcom.com with esmtp (Exim 4.14) id 1NYnCs-0008K7-4P for rsgb_lf_group@blacksheep.org; Sat, 23 Jan 2010 21:07:46 +0000 Received: from out1.ip08ir2.opaltelecom.net ([62.24.128.244]) by relay3.thorcom.net with esmtp (Exim 4.63) (envelope-from ) id 1NYnCp-00089M-FR for rsgb_lf_group@blacksheep.org; Sat, 23 Jan 2010 21:07:46 +0000 X-IronPort-Anti-Spam-Filtered: true X-IronPort-Anti-Spam-Result: AosFAHb0WktOlECv/2dsb2JhbAAtjUcFx0iEOwQ X-IronPort-AV: E=Sophos;i="4.49,330,1262563200"; d="scan'208,217";a="437549030" Received: from unknown (HELO xphd97xgq27nyf) ([78.148.64.175]) by out1.ip08ir2.opaltelecom.net with SMTP; 23 Jan 2010 21:07:25 +0000 Message-ID: <00c501ca9c70$0d6dcb90$0401a8c0@xphd97xgq27nyf> From: "mal hamilton" To: References: <9afca2641001230548m3538db64y92b335aa75c1dc00@mail.gmail.com> <9afca2641001230643s4cf01377h70165d22d325dbe1@mail.gmail.com> <9afca2641001230852x7c870d8r3837c9b6eb60c67b@mail.gmail.com> <007201ca9c5d$3614e0f0$0401a8c0@xphd97xgq27nyf> <9afca2641001231117y223fea2cgb37f658c04708e2c@mail.gmail.com> <008e01ca9c62$d9c0a6d0$0401a8c0@xphd97xgq27nyf> <9afca2641001231215hf5edc24ve8f75cf4968600d6@mail.gmail.com> Date: Sat, 23 Jan 2010 21:07:20 -0000 MIME-Version: 1.0 X-Priority: 3 X-MSMail-Priority: Normal X-Mailer: Microsoft Outlook Express 6.00.2600.0000 X-MimeOLE: Produced By Microsoft MimeOLE V6.00.2600.0000 X-Spam-Score: 1.2 (+) X-Spam-Report: autolearn=disabled,BIZ_TLD=1.169,HTML_MESSAGE=0.001 Subject: Re: LF: JT4A simple guide? Content-Type: multipart/alternative; boundary="----=_NextPart_000_00C2_01CA9C70.0D3E3010" X-Spam-Checker-Version: SpamAssassin 2.63 (2004-01-11) on post.thorcom.com X-Spam-Level: * X-Spam-Status: No, hits=1.7 required=5.0 tests=BIZ_TLD,HTML_30_40, HTML_FONTCOLOR_UNSAFE,HTML_MESSAGE 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: 3039ac1d410a4b5b65602b24 X-AOL-IP: 193.82.116.20 ------=_NextPart_000_00C2_01CA9C70.0D3E3010 Content-Type: text/plain; charset="iso-8859-1" Content-Transfer-Encoding: quoted-printable There cannot be a time when JT4 or WSPR will be received and not QRS= because the trace is always visible long before a data decode. There= has never been a case of an INVISIBLE trace and a data decode. The si= gnal trace is always VISIBLE and therefore if KEYED would convey the= transmitted message. G3KEV ----- Original Message -----=20 From: Roger Lapthorn=20 To: rsgb_lf_group@blacksheep.org=20 Sent: Saturday, January 23, 2010 8:15 PM Subject: Re: LF: JT4A simple guide? Mal, There will be times when this may be true, but modes like WSPR and,= I expect, JT4A will get through when signals are extremely weak when= CW simply would not. =20 Here's an idea: why not turning your ERP down to 1mW for a few weeks= and see how you get on?=20 73s Roger G3XBM On 23 January 2010 19:32, mal hamilton wrote= : Obviously not reading recent postings about no decodes from others= although the signals are visible, like I said these signals are not= onljy visible with me but audible so why complicate matters, just sen= d qrs or cw in the first place. Some one even mentioned DUMMIES, there are a lot of these about.= Dummies alias Appliance operators The word is ill-informedtry=20 g3kev ----- Original Message -----=20 From: Roger Lapthorn=20 To: rsgb_lf_group@blacksheep.org=20 Sent: Saturday, January 23, 2010 7:17 PM Subject: Re: LF: JT4A simple guide? Mal informed. On 23 January 2010 18:52, mal hamilton = wrote: I still see these data signals as a waste of time since had th= e carrier been keyed I could read them 100% without having to wait for= the right circumstance to get a decode, no need for level 2 demodulat= ion. There are several traces now visible but only an odd decode!!!= !!!!!!!!!!!! Try a QRS or CW QSO if you need an immdediate report. Th= ese signals are audible with me. g3kev ----- Original Message -----=20 From: Roger Lapthorn=20 To: rsgb_lf_group@blacksheep.org=20 Sent: Saturday, January 23, 2010 4:52 PM Subject: Re: LF: JT4A simple guide? Ok, fully understand Andy. Jim G7NKS is sending JT4A but I'= m not getting any decodes yet. Roger G3XBM On 23 January 2010 16:38, Andy Talbot wrote: After posting that, I realised the JT4 PIC/DDS beacon code= is designed for 100% duty cycle operation, viz JT4, CW + carrier, whi= ch is a bit antisocial (certainly the wide bandwidth CW bit). And mor= e importantly, as my PA is a low efficiency clas AB linear one - enoug= h said... To adapt for low duty cycle would need the PIC code changi= ng, so will put the idea on hold unles there is a real demand. For= a beacon, WSPR has more to offer anyway. Incidently, WSPR and JT4 are the same mode anyway, albeit= with a bandwidth change from 1.46 to 4.375Hz with a resulting 4.75dB= reduction in S/N. The coding and demodulation are all the same, so= this bandwidth difference should be directly detectable between the= two modes. The differing message contents wont affect the efficiency= , its the added error correction , sync and modulation that matters -= and they use the same algorithm. Andy www.g4jnt.com On 23 January 2010 14:43, Roger Lapthorn wrote: Thanks for this help Andy.=20 I'd not like to derive others of your valuable 500kHz WS= PR beacon, but could you beacon in JT4A at certain pre-arranged times= or days perhaps? If JT4A looks like offering the possibility of reall= y weak signal QSOs to people like me running flea-power then I'd like= to explore the mode some more and having a reliable signal to test wi= th initially would be useful. I am sure there will be others who would= value this too. 73s Roger G3XBM=20 On 23 January 2010 14:26, Andy Talbot wrote: AFAIK The is no 'simple guide' JT4x was never origin= ally going to be one of Joe's supported modes, although after our exte= nsive use on uWaves it certainly is now. JT65x was the more popular= and documented code, being heavily used for EME on 144 / 432 / 1296MH= z, with JT4x just one of those included in the WSJT suite to 'try ou= t' If you download and read the WSJT users guide and other supportin= g files, there's all you need to know to get it going is in there. http://www.physics.princeton.edu/pulsar/K1JT/WSJT_User= _600.pdf =20 http://www.physics.princeton.edu/pulsar/K1JT/wsjt.html http://www.physics.princeton.edu/pulsar/K1JT/JT2_JT4.T= XT Its still debatable as to whether JT4 is better or wor= se than JT65x, but at least it does have the options of being availabl= e in a range of bandwidths / tone spacings making it usable from DC to= red light. (Although I think I've only ever come across A, D and G= being used respectively on LF, HF and uWaves) There's probably onl= y a fraction of a dB in it and both are, as far as I can ascertain, on= ly a dB or two away from the Shannon limit. [Which knocks spots off= CW or any fuzzy mode, as well as straight PSKnn without error correct= ion]. Wolf has a similar signalling efficiency, but unfortunately is= wider, needs a linear TX to avoid being too wide and seems less user= friendly. A year or so ago we (the microwave community) wanted= something for use on 1.3GHz and up to 10GHz or beyond. JT4G, the wid= est spaced varient of them looked suitable. After some prompting,= Joe was persuaded not to abandon that mode, and in fact he modified= the code to enhance the decoder routine so the wide spaced version= would be decoded with the same S/N as JT4A. We discovered just how= good the mode was, even under severe rainscatter conditions where eac= h tone was spread out to 200Hz bandwidth (tone spacing in JT4G is 315H= z for 1kH zwide overall, so this rain scattered signal still had discr= ete tone energy). There are now two microwave beacons that transmit JT4G= waveforms, the 10 and 2.3GHz ones in Dorset GB3SCX and GB3SCS www.= scrbg.org and now GB3CSB on 1.3GHz from central Scotland http://ww= w.rayjames.biz/gm4cxm/id14.html Other will follow before long as it= is quite an easy mode to generate from a simple PIC keyer provided ac= curate timing information is available to keep it synched. =20 My beacon engine - the one that currently drives the= 503.7/503.85 signals - can give JT4A immediately just by reprogrammin= g the PIC. Would there be any interest, bearing in mind both the WSP= R and "5MHz type" waveforms will be lost for the duration? Andy www.g4jnt.com This email has been scanned for damaging side-effects= by the health and safety police, is guaranteed to contain no substanc= es hazardous to health, but may contribute to dissolving the nether an= d polar regions On 23 January 2010 13:48, Roger Lapthorn wrote: Having looked on the WSJT website there is little (n= o?) reference to JT4A in the help files. I assume it is similar to mo= des like JT6M which I have managed to receive in the past on 50MHz but= never tried TXing. Can someone point me in the direction of a "JT4A for= Dummies" guide, or something similar that I might understand, please? 73s Roger G3XBM --=20 http://g3xbm-qrp.blogspot.com/ http://www.g3xbm.co.uk http://www.youtube.com/user/G3XBM G3XBM GQRP 1678 ISWL G11088 --=20 http://g3xbm-qrp.blogspot.com/ http://www.g3xbm.co.uk http://www.youtube.com/user/G3XBM G3XBM GQRP 1678 ISWL G11088 --=20 http://g3xbm-qrp.blogspot.com/ http://www.g3xbm.co.uk http://www.youtube.com/user/G3XBM G3XBM GQRP 1678 ISWL G11088 --=20 http://g3xbm-qrp.blogspot.com/ http://www.g3xbm.co.uk http://www.youtube.com/user/G3XBM G3XBM GQRP 1678 ISWL G11088 --=20 http://g3xbm-qrp.blogspot.com/ http://www.g3xbm.co.uk http://www.youtube.com/user/G3XBM G3XBM GQRP 1678 ISWL G11088 ------=_NextPart_000_00C2_01CA9C70.0D3E3010 Content-Type: text/html; charset="iso-8859-1" Content-Transfer-Encoding: quoted-printable
There cannot be a time when JT4 or WS= PR will be=20 received and not QRS because the trace is always visible long before= a data=20 decode. There has never been a case of an INVISIBLE trace and a data= decode. The=20 signal trace is always VISIBLE and therefore if KEYED would convey the= =20 transmitted message.
 
G3KEV
----- Original Message -----
Sent: Saturday, January 23,= 2010 8:15=20 PM
Subject: Re: LF: JT4A simple= guide?

Mal,

There will be times when this may be true= , but=20 modes like WSPR and, I expect, JT4A will get through when signals ar= e=20 extremely weak when CW simply would not. 

Here's= an idea:=20 why not turning your ERP down to 1mW for a few weeks and see how you= get on?=20

73s
Roger G3XBM



On 23 January 2010 19:32, mal hamilton <g3kev= mal@talktalk.net>=20 wrote:
Obviously not reading recent post= ings about no=20 decodes from others although the signals are visible, li= ke I said=20 these signals are not onljy visible with me but audible so why com= plicate=20 matters, just send qrs or cw in the first place.
Some one even mentioned DUMMIES,= there are a=20 lot of these about. Dummies alias Appliance operators
The word is ill-informedtry
<= /FONT>
g3kev
 
-----=20 Original Message -----
From:=20 Roger Lapthorn
Sent:=20 Saturday, January 23, 2010 7:17 PM
Subject:=20 Re: LF: JT4A simple guide?

Mal informed.

On 23 January 2010 18:52, mal hamilton= <g3kevmal@talktalk.net> wrote:
I still see these data signal= s as a waste=20 of time since had the carrier been keyed I could read them 100= % without=20 having to wait for the right circumstance to get a decode, no= need for=20 level 2 demodulation.
There are several traces now= visible but=20 only an odd decode!!!!!!!!!!!!!!! Try a QRS or CW QS= O  if=20 you need an immdediate report. These signals are audible with= =20 me.
 
 
 
g3kev
 
-----=20 Original Message -----
From:=20 Roger Lapthorn
Sent:=20 Saturday, January 23, 2010 4:52 PM
Subject:=20 Re: LF: JT4A simple guide?

Ok, fully understand Andy.  Jim G7NKS is sending= JT4A but=20 I'm not getting any decodes yet.

Roger G3XBM

On 23 January 2010 16:38, Andy Talb= ot <andy.g4jnt@googlemail.com>= ; wrote:
After posting that, I realised the JT4 PIC/DDS beacon= code is=20 designed for 100% duty cycle operation, viz JT4, CW + carr= ier, which=20 is a bit antisocial (certainly the wide bandwidth CW bit).=   And=20 more importantly, as my PA is a low efficiency clas AB lin= ear one -=20 enough said...
 
To adapt for low duty cycle would need the PIC code= changing,=20 so will put the idea on hold unles there is a real=20 demand.   For a beacon, WSPR has more to offer= =20 anyway.
 
Incidently, WSPR and JT4 are the same mode anyway, al= beit with=20 a bandwidth change from 1.46 to 4.375Hz  with a resul= ting=20 4.75dB reduction in S/N.  The coding and demodulation= are all=20 the same, so this bandwidth difference should be=20 directly detectable between the two modes. = The=20 differing message contents wont affect the efficiency, its= the added=20 error correction , sync and modulation that matters= - and they=20 use the same algorithm.
On 23 January 2010 14:43, Roger= Lapthorn=20 <rogerlapthorn@gmail.com> wrote:
Thanks=20 for this help Andy.

I'd not like to derive other= s of your=20 valuable 500kHz WSPR beacon, but could you beacon in JT4= A at=20 certain pre-arranged times or days perhaps? If JT4A look= s like=20 offering the possibility of really weak signal QSOs to= people like=20 me running flea-power then I'd like to explore the mode= some more=20 and having a reliable signal to test with initially woul= d be=20 useful. I am sure there will be others who would value= this=20 too.

73s
Roger G3XBM=20



On 23 January 2010 14:26, Andy= Talbot <andy.g4jnt@googlema= il.com> wrote:
AFAIK The is no 'simple guide'   JT4x= was never=20 originally going to be one of Joe's supported modes,= although=20 after our extensive use on uWaves it certainly&nb= sp;is=20 now.   JT65x was the more popular and docume= nted code,=20 being heavily used for EME on 144 / 432=20 / 1296MHz,   with JT4x just one of thos= e included=20 in the WSJT suite to 'try out'   If you down= load and=20 read the WSJT users guide and other supporting fi= les,=20 there's all you need to know to get it going is= in=20 there.
 
 
Its still debatable as to whether JT4 is better= or worse=20 than JT65x, but at least it does have the options of= being=20 available in a range of bandwidths / tone spacings mak= ing it=20 usable from DC to red light.   (Although I= think I've=20 only ever come across A, D and G being used respective= ly on LF,=20 HF and uWaves)    There's probably only= a=20 fraction of a dB in it and both are, as far as I can= ascertain,=20 only a dB or two away from the Shannon limit.  [W= hich=20 knocks spots off CW or any fuzzy mode, as well as stra= ight=20 PSKnn without error correction].   Wolf= has a=20 similar signalling efficiency, but unfortunately is wi= der, needs=20 a linear TX to avoid being too wide and seems less use= r=20 friendly.
 
A year or so ago we (the microwave community) wan= ted=20 something for use on 1.3GHz and up to 10GHz or=20 beyond.  JT4G, the widest spaced varient of= =20 them looked suitable.    After som= e=20 prompting, Joe was persuaded not to abandon that mode,=   and=20 in fact he modified the code to  enhanc= e the=20 decoder routine so the wide spaced version would be de= coded with=20 the same S/N as JT4A.    We discovered= just how=20 good the mode was, even under severe rainscatter condi= tions=20 where each tone was spread out to 200Hz bandwidth (ton= e spacing=20 in JT4G is 315Hz for 1kH zwide overall, so this rain= scattered=20 signal still had discrete tone energy).
 
There are now two microwave beacons that transmit= JT4G=20 waveforms,   the 10 and 2.3GHz ones in Dorse= t =20 GB3SCX and GB3SCS www.scrbg.org    and&n= bsp; now=20 GB3CSB on 1.3GHz from central Scotland http://www.rayjames.biz/gm4cxm/id14.html&n= bsp;=20 Other will follow before long as it is quite an easy= mode to=20 generate from a simple PIC keyer provided accurate tim= ing=20 information is available to keep it synched. &nbs= p;
 
My beacon engine - the one that currently drives= the=20 503.7/503.85 signals - can give JT4A immediately= just by=20 reprogramming the PIC.   Would there be any= interest,=20 bearing in mind both the WSPR and "5MHz type= "=20 waveforms will be lost for the duration?

Andy
www.g4jnt.com

Th= is email has been=20 scanned for damaging side-effects by the health and sa= fety=20 police, is guaranteed to contain no substances hazardo= us to=20 health, but may contribute to dissolving the nether an= d polar=20 regions


On 23 January 2010 13:48, Rog= er Lapthorn=20 <rogerlapthorn@gmail.com= > wrote:
Having=20 looked on the WSJT website there is little (no?)&nbs= p;=20 reference to JT4A in the help files. I assume it is= similar to=20 modes like JT6M which I have managed to receive in= the past on=20 50MHz but never tried TXing.

Can someone poin= t me in=20 the direction of a "JT4A for Dummies" guide,= or=20 something similar that I might understand,=20 please?

73s
Roger G3XBM

--

http://g3xbm-qrp.blogspot.com/
http://www.g3xbm.co.uk
http://www.youtube.com/user/G3XBM
G3XBM=20    GQRP 1678      ISWL=20 G11088

=



--

= http://g3xbm-qrp.blogspot.com/
http://www.g3= xbm.co.uk
http://www.youtube.com/user/G= 3XBM
G3XBM=20    GQRP 1678      ISWL=20 G11088




--

h= ttp://g3xbm-qrp.blogspot.com/
http://www.g3xbm.co.ukhttp://www.youtube.com/user/G3XBM
G3XBM &nb= sp;=20  GQRP 1678      ISWL=20 G11088


--

http://g3xbm-qrp.blogspot.com/
http://www.g3xbm.co.uk
http://www.youtube.com/user/G= 3XBM
G3XBM  =20  GQRP 1678      ISWL=20 G11088


--

http://g3xbm-qrp.blogspot.com/
http://www.g3xbm.co.uk
http://www.youtube.com/user/G3XBM
G3= XBM=20    GQRP 1678      ISWL=20 G11088
------=_NextPart_000_00C2_01CA9C70.0D3E3010--