Return-Path: Received: from rly-me08.mx.aol.com (rly-me08.mail.aol.com [172.20.83.42]) by air-me04.mail.aol.com (v126.13) with ESMTP id MAILINME042-9cd4b5b5940258; Sat, 23 Jan 2010 15:17:26 -0500 Received: from post.thorcom.com (post.thorcom.com [193.82.116.20]) by rly-me08.mx.aol.com (v125.7) with ESMTP id MAILRELAYINME081-9cd4b5b5940258; Sat, 23 Jan 2010 15:17:06 -0500 Received: from majordom by post.thorcom.com with local (Exim 4.14) id 1NYmOg-0007mK-7W for rs_out_1@blacksheep.org; Sat, 23 Jan 2010 20:15:54 +0000 Received: from [83.244.159.144] (helo=relay3.thorcom.net) by post.thorcom.com with esmtp (Exim 4.14) id 1NYmOf-0007mB-4Z for rsgb_lf_group@blacksheep.org; Sat, 23 Jan 2010 20:15:53 +0000 Received: from mail-bw0-f221.google.com ([209.85.218.221]) by relay3.thorcom.net with esmtp (Exim 4.63) (envelope-from ) id 1NYmOd-0007o0-53 for rsgb_lf_group@blacksheep.org; Sat, 23 Jan 2010 20:15:53 +0000 Received: by bwz21 with SMTP id 21so1840312bwz.4 for ; Sat, 23 Jan 2010 12:15:45 -0800 (PST) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=gmail.com; s=gamma; h=domainkey-signature:mime-version:received:in-reply-to:references :date:message-id:subject:from:to:content-type; bh=CiETyQBSXixOWfDzdQBjmapm5SE6GoWVI0Qm40ygqpM=; b=QXlwLNJq0F79Hq3AYYr0MgH/yaG2cfDDEyaJ5yO4lVKdEAMjMzGmiFsx2Ym6U/FRkx kdz/msUpc99GevFpHzk0TAP0HZI9YVd9ZCtBgugpoffSKJdtn6HL/nc+queT9vI/rUZL k8FxlUuMQJvouzACn2T9BM5YV1RkGux2yLzy8= DomainKey-Signature: a=rsa-sha1; c=nofws; d=gmail.com; s=gamma; h=mime-version:in-reply-to:references:date:message-id:subject:from:to :content-type; b=BfMorSMZ6x8+IY1d4fs4TE3G53UN7QV74wDW7jpojKP1yZ9GFv8wkdgHvTHC344wz5 64hogUhF9DTcHt2kkk+djdyTP3W1jdVKs/M1UKr8mDcTLh3XkVoaS+/bogk8ImQFf2++ b0wA5UG3BaKDeRHY8vBApCZ+AOX/T81fHEY2o= MIME-Version: 1.0 Received: by 10.204.10.20 with SMTP id n20mr2601280bkn.33.1264277744948; Sat, 23 Jan 2010 12:15:44 -0800 (PST) In-Reply-To: <008e01ca9c62$d9c0a6d0$0401a8c0@xphd97xgq27nyf> 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> Date: Sat, 23 Jan 2010 20:15:44 +0000 Message-ID: <9afca2641001231215hf5edc24ve8f75cf4968600d6@mail.gmail.com> From: Roger Lapthorn To: rsgb_lf_group@blacksheep.org DomainKey-Status: good (testing) 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=00032555a0d2e297b2047dda9915 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-IP: 193.82.116.20 X-AOL-SCOLL-AUTHENTICATION: mail_rly_antispam_dkim-d226.1 ; domain : gmail.com DKIM : pass X-Mailer: Unknown (No Version) --00032555a0d2e297b2047dda9915 Content-Type: text/plain; charset=ISO-8859-1 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. Here's an idea: why not turning your ERP down to 1mW for a few weeks and see how you get on? 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 send 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 > g3kev > > > ----- Original Message ----- > *From:* Roger Lapthorn > *To:* rsgb_lf_group@blacksheep.org > *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 the 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 demodulation. >> There are several traces now visible but only an odd decode!!!!!!!!!!!!!!! >> Try a QRS or CW QSO if you need an immdediate report. These signals are >> audible with me. >> >> >> >> g3kev >> >> >> ----- Original Message ----- >> *From:* Roger Lapthorn >> *To:* rsgb_lf_group@blacksheep.org >> *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, which is a bit >>> antisocial (certainly the wide bandwidth CW bit). And more importantly, as >>> my PA is a low efficiency clas AB linear one - enough said... >>> >>> To adapt for low duty cycle would need the PIC code changing, 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. >>>> >>>> I'd not like to derive others of your valuable 500kHz WSPR beacon, but >>>> could you beacon in JT4A at certain pre-arranged times or days perhaps? If >>>> JT4A looks like offering the possibility of really 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 with initially would be useful. I >>>> am sure there will be others who would value this too. >>>> >>>> 73s >>>> Roger G3XBM >>>> >>>> >>>> >>>> On 23 January 2010 14:26, Andy Talbot wrote: >>>> >>>>> AFAIK The is no 'simple guide' JT4x was never originally going to be >>>>> one of Joe's supported modes, although after our extensive use on uWaves it >>>>> certainly is now. JT65x was the more popular and documented code, being >>>>> heavily used for EME on 144 / 432 / 1296MHz, with JT4x just one of those >>>>> included in the WSJT suite to 'try out' If you download and read the >>>>> WSJT users guide and other supporting 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 >>>>> *http://www.physics.princeton.edu/pulsar/K1JT/wsjt.html* >>>>> http://www.physics.princeton.edu/pulsar/K1JT/JT2_JT4.TXT >>>>> >>>>> Its still debatable as to whether JT4 is better or worse than JT65x, >>>>> but at least it does have the options of being available 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 only a fraction of a >>>>> dB in it and both are, as far as I can ascertain, only 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 correction]. 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 widest 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 each tone was spread out to 200Hz bandwidth >>>>> (tone spacing in JT4G is 315Hz for 1kH zwide overall, so this rain scattered >>>>> signal still had discrete 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://www.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 accurate timing information is available to keep it synched. >>>>> >>>>> My beacon engine - the one that currently drives the 503.7/503.85 >>>>> signals - can give JT4A immediately just by reprogramming the PIC. Would >>>>> there be any interest, bearing in mind both the WSPR 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 substances hazardous to health, >>>>> but may contribute to dissolving the nether and polar regions >>>>> >>>>> >>>>> On 23 January 2010 13:48, Roger Lapthorn wrote: >>>>> >>>>>> Having looked on the WSJT website there is little (no?) reference to >>>>>> JT4A in the help files. I assume it is similar to modes 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 >>>>>> >>>>>> -- >>>>>> >>>>>> http://g3xbm-qrp.blogspot.com/ >>>>>> http://www.g3xbm.co.uk >>>>>> http://www.youtube.com/user/G3XBM >>>>>> G3XBM GQRP 1678 ISWL G11088 >>>>>> >>>>> >>>>> >>>> >>>> >>>> -- >>>> >>>> http://g3xbm-qrp.blogspot.com/ >>>> http://www.g3xbm.co.uk >>>> http://www.youtube.com/user/G3XBM >>>> G3XBM GQRP 1678 ISWL G11088 >>>> >>> >>> >> >> >> -- >> >> http://g3xbm-qrp.blogspot.com/ >> http://www.g3xbm.co.uk >> http://www.youtube.com/user/G3XBM >> G3XBM GQRP 1678 ISWL G11088 >> >> > > > -- > > http://g3xbm-qrp.blogspot.com/ > http://www.g3xbm.co.uk > http://www.youtube.com/user/G3XBM > G3XBM GQRP 1678 ISWL G11088 > > -- http://g3xbm-qrp.blogspot.com/ http://www.g3xbm.co.uk http://www.youtube.com/user/G3XBM G3XBM GQRP 1678 ISWL G11088 --00032555a0d2e297b2047dda9915 Content-Type: text/html; charset=ISO-8859-1 Content-Transfer-Encoding: quoted-printable 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 we= ak when CW simply would not.=A0

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

73s
Roger G3XBM



On 23 Jan= uary 2010 19:32, mal hamilton <g3kevmal@talktalk.net> wrote:
Obviously not reading recent postings= about no=20 decodes=A0from others=A0although the signals are visible, like I said=20 these signals are not onljy visible with me but audible so why complicate= =20 matters, just send qrs or cw in the first place.
Some one even mentioned DUMMIES, ther= e are a lot of=20 these about. Dummies alias Appliance operators
The word is ill-informedtry
g3kev
=A0
----- Original Message -----
Subject: Re: LF: JT4A simple gu= ide?

Mal informed.

On 23 January 2010 18:52, mal hamilton <g3kevmal@talktalk.net>=20 wrote:
I still see these data signals as= a waste of=20 time since had the carrier been keyed I could read them 100% without= having=20 to wait for the right circumstance to get a decode, no need for level= 2=20 demodulation.
There are several traces now visi= ble but only=20 an odd decode!!!!!!!!!!!!!!! Try a=A0QRS or CW=A0QSO =A0if you need=20 an immdediate report. These signals are audible with me.
=A0
=A0
=A0
g3kev
=A0
-----=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.=A0 Jim G7NKS is sending JT4A=20 but I'm not getting any decodes yet.

Roger G3XBM

On 23 January 2010 16:38, Andy Talbot <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 + carrier, whi= ch is=20 a bit antisocial (certainly the wide bandwidth CW bit).=A0 And mor= e=20 importantly, as my PA is a low efficiency clas AB linear one - eno= ugh=20 said...
=A0
To adapt for low duty cycle would need the PIC code changing,= so=20 will put the idea on hold unles there is a real demand.=A0=A0 For= =20 a beacon, WSPR has more to offer anyway.
=A0
Incidently, WSPR and JT4 are the same mode anyway, albeit wit= h a=20 bandwidth change from 1.46 to 4.375Hz=A0 with a resulting 4.75dB= =20 reduction in S/N.=A0 The coding and demodulation are all the same,= so=20 this bandwidth difference should be=20 directly=A0detectable=A0between the two modes.=A0 The differing=20 message contents wont affect the efficiency, its the added error= =20 correction , sync and modulation=A0that matters - and they use the= =20 same algorithm.
On 23 January 2010 14:43, Roger Lapthor= n <rogerlapthorn@gmail.com> wrote:
Thanks= =20 for this help Andy.

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

73s
Rog= er=20 G3XBM=20



On 23 January 2010 14:26, Andy Talbot= <andy.g4jnt@googlemail.com> wrote:
AFAIK The is no 'simple guide'=A0=A0 JT4x was nev= er=20 originally going to be one of Joe's supported modes, altho= ugh after=20 our extensive use=A0on uWaves it certainly=A0is=20 now.=A0=A0 JT65x was the more popular and documented code,=20 being heavily used for EME on 144=A0/ 432 /=A01296MHz,=A0=20 =A0with JT4x just one of those included in the WSJT suite to= 'try=20 out'=A0=A0 If you download and read the WSJT=A0users guide= =20 and other supporting files, there's=A0all you need to know= to get=20 it going is in there.
=A0
=A0
Its still debatable as to whether JT4 is better or worse= than=20 JT65x, but at least it does have the options of being availabl= e in a=20 range of bandwidths / tone spacings making it usable from DC= to red=20 light.=A0=A0 (Although I think I've only ever come across= A, D=20 and G being used respectively on LF, HF and=20 uWaves)=A0=A0=A0 There's probably only a fraction of a dB= =20 in it and both are, as far as I can ascertain, only a dB or tw= o away=20 from the Shannon limit.=A0 [Which knocks spots off CW or any= =20 fuzzy mode, as well as straight PSKnn=A0without error=20 correction].=A0=A0 Wolf has a similar signalling efficiency,= =20 but unfortunately is wider, needs a linear TX to avoid being= too=20 wide and seems less user friendly.
=A0
A year or so ago we (the microwave community) wanted some= thing=20 for use=A0on 1.3GHz and up to 10GHz or beyond.=A0=A0JT4G,=20 the widest spaced varient of them=A0looked=20 suitable.=A0=A0=A0 After some prompting, Joe was persuaded=20 not to abandon that mode,=A0 and in fact=A0he=A0modified=20 the code to =A0enhance the decoder routine so the wide spaced= =20 version would be decoded with the same S/N as=20 JT4A.=A0=A0=A0 We discovered just how good the mode was,=20 even under severe rainscatter conditions where each tone was= spread=20 out to 200Hz bandwidth (tone spacing in JT4G is 315Hz for 1kH= zwide=20 overall, so this rain scattered signal still had discrete tone= =20 energy).
=A0
There are now two microwave beacons that transmit JT4G=20 waveforms,=A0=A0 the 10 and 2.3GHz ones in Dorset=A0 GB3SCX=20 and GB3SCS www.scrbg.org=A0 =A0 and=A0 now GB3CSB on=20 1.3GHz from central Scotland http://www.rayjames.biz/gm4cxm/id14.= html=A0=20 Other will follow before long as it is quite an easy mode to= =20 generate from a simple PIC keyer provided accurate timing=20 information is available to keep it synched.=A0=A0
=A0
My beacon engine - the one that currently drives the=20 503.7/503.85 signals -=A0can give JT4A immediately just by=20 reprogramming the PIC.=A0=A0 Would there be any interest,=20 bearing in mind=A0both the=A0WSPR and "5MHz type" wa= veforms=20 will be lost for the duration?

Andy
www.g4jnt.com

This email has been scanned= =20 for damaging side-effects by the health and safety police, is= =20 guaranteed to contain no substances hazardous to health, but= may=20 contribute to dissolving the nether and polar=20 regions


On 23 January 2010 13:48, Roger Lap= thorn=20 <rogerlapthorn@gmail.com> wrote:
Hav= ing=20 looked on the WSJT website there is little (no?)=A0 referenc= e=20 to JT4A in the help files. I assume it is similar to modes= like=20 JT6M which I have managed to receive in the past on 50MHz bu= t=20 never tried TXing.

Can someone point me in the direct= ion of=20 a "JT4A for Dummies" guide, or something si= milar that I=20 might understand, please?

73s
Roger G3XBM

--

http://g3xbm-qrp.blogspot.com/
<= a href=3D"http://www.g3xbm.co.uk/" target=3D"_blank">http://www.g3xbm.co.u= k
http://www= .youtube.com/user/G3XBM
G3XBM=20 =A0 =A0GQRP 1678 =A0 =A0 =A0ISWL=20 G11088




--

http://g3xbm-qrp.blogspot.com/
http://www.g3xbm.co.uk=
http://www= .youtube.com/user/G3XBM
G3XBM =A0=20 =A0GQRP 1678 =A0 =A0 =A0ISWL=20 G11088




--

http://g3xbm-qrp.blogspot.com/
http://www.g3xbm.co.uk<= /a>
http://www= .youtube.com/user/G3XBM
G3XBM =A0=20 =A0GQRP 1678 =A0 =A0 =A0ISWL=20 G11088



--

http://g3xbm-qrp.blogspot.com/
http://www.g3xbm.co.uk
http://www= .youtube.com/user/G3XBM
G3XBM=20 =A0 =A0GQRP 1678 =A0 =A0 =A0ISWL=20 G11088



--

http://g3xbm-qrp.blogspot.com/
http://www.g3xbm.co.uk
http://www.youtube.com/user/G3XBM
G3XBM =A0 =A0GQRP 1678 =A0 =A0 =A0ISWL G11088
--00032555a0d2e297b2047dda9915--