Return-Path: Received: from mtain-me01.r1000.mx.aol.com (mtain-me01.r1000.mx.aol.com [172.29.96.137]) by air-di06.mail.aol.com (v129.4) with ESMTP id MAILINDI061-eaca4c5293c2328; Fri, 30 Jul 2010 04:56:34 -0400 Received: from post.thorcom.com (post.thorcom.com [193.82.116.20]) by mtain-me01.r1000.mx.aol.com (Internet Inbound) with ESMTP id 20D62380001DB; Fri, 30 Jul 2010 04:56:32 -0400 (EDT) Received: from majordom by post.thorcom.com with local (Exim 4.14) id 1OelNI-0005HV-B6 for rs_out_1@blacksheep.org; Fri, 30 Jul 2010 09:55:28 +0100 Received: from [193.82.116.32] (helo=relay1.thorcom.net) by post.thorcom.com with esmtp (Exim 4.14) id 1OelNH-0005HM-O6 for rsgb_lf_group@blacksheep.org; Fri, 30 Jul 2010 09:55:27 +0100 Received: from relay2.uni-heidelberg.de ([129.206.210.211]) by relay1.thorcom.net with esmtp (Exim 4.63) (envelope-from ) id 1OelNF-0006Fd-TE for rsgb_lf_group@blacksheep.org; Fri, 30 Jul 2010 09:55:27 +0100 Received: from freitag.iup.uni-heidelberg.de (freitag.iup.uni-heidelberg.de [129.206.29.204]) by relay2.uni-heidelberg.de (8.13.8/8.13.8) with ESMTP id o6U8t6s8009394 (version=TLSv1/SSLv3 cipher=DHE-RSA-AES256-SHA bits=256 verify=NO) for ; Fri, 30 Jul 2010 10:55:07 +0200 Received: from [129.206.29.99] (pc99.iup.uni-heidelberg.de [129.206.29.99]) by freitag.iup.uni-heidelberg.de (8.12.11.20060308/8.11.2) with ESMTP id o6U8tOk6024119 for ; Fri, 30 Jul 2010 10:55:24 +0200 Message-ID: <4C529331.3090909@iup.uni-heidelberg.de> Date: Fri, 30 Jul 2010 10:54:09 +0200 From: =?ISO-8859-1?Q?Stefan_Sch=E4fer?= User-Agent: Mozilla/5.0 (Windows; U; Windows NT 6.1; de; rv:1.9.1.8) Gecko/20100227 Thunderbird/3.0.3 MIME-Version: 1.0 To: rsgb_lf_group@blacksheep.org References: <4C51FA69.1030202@iup.uni-heidelberg.de> In-Reply-To: X-Spam-Score: 1.4 (+) X-Spam-Report: autolearn=disabled,HTML_MESSAGE=0.001,RATWARE_GECKO_BUILD=1.426 Subject: Re: LF: Digital modes comparison Content-Type: multipart/alternative; boundary="------------070604020504010301040405" X-Spam-Checker-Version: SpamAssassin 2.63 (2004-01-11) on post.thorcom.com X-Spam-Level: X-Spam-Status: No, hits=0.5 required=5.0 tests=HTML_20_30,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: 3039ac1d60894c5293c0673d X-AOL-IP: 193.82.116.20 X-Mailer: Unknown (No Version) --------------070604020504010301040405 Content-Type: text/plain; charset=ISO-8859-1; format=flowed Content-Transfer-Encoding: quoted-printable X-MIME-Autoconverted: from 8bit to quoted-printable by relay2.uni-heidelberg.de id o6U8t6s8009394 Roger, VLF, I will check the resonance curve in the next experiment. Maybe it is=20 higher than expected due to the high R in that RLC-circuit... So maybe=20 there are even some many Hz available... Stefan/DK7FC Am 30.07.2010 09:58, schrieb Roger Lapthorn: > Andy, > > Would a variant of WSPR be possible that uses a slower FSK rate over,=20 > for example, a 4 minute TX period? Would a half speed WSPR convey the=20 > same data in twice as long but only occupy 3Hz bandwidth? This of=20 > course assumes K1JT has nothing better to do! > > 73s > Roger G3XBM > > On 30 July 2010 08:54, Roger Lapthorn > wrote: > > Presumably "QRSS very very slow" is better still, but here this > issue is the time to get data through. Andy, I assume that you're > saying WSPR or JT4A give the best "data per bandwidth per given time= "? > > 73s > Roger G3XBM > > > On 30 July 2010 08:17, Andy Talbot > wrote: > > Try WSPR at 6Hz bandwidth or JT4A at less that 20Hz. They > are both MSFK constant envelope schemes. > > Andy > www.g4jnt.com > > > 2010/7/29 Stefan Sch=E4fer > > > Andy, LF, > > Which digital mode could be most suited for a band where > one has just an antenna bandwidth of some Hz? You know > what i mean... And what could be the "gain" compared to > DFCW-600. Gain means here, how far(er) could it be > detected, not how much more information can i transmit > within the same time. > > 73, Stefan/DK7FC > > PS: I see that e.g. JT65 needs abt 200 Hz, so this NOT suite= d! > > > Am 29.07.2010 23:07, schrieb Andy Talbot: >> It would be very interesting to see those figures >> normalised to a constant data rate / bandwidth. For >> example, PSK31 shown at -10dB is identical to PKK63 at >> -7dB - well it would be, its the same modulation, just >> faster. Ie plot Bits/second/Hz vs. Eb/No, then stick >> the Shannon limit on the graph and see which lie nearest. >> The fact that JT65 is at the top is probably because it >> sits at around 0.27 chars / second, or something like 1.2 >> B/s. Although even after normalisation, it would no >> doubt still score well up. >> >> Andy >> www.g4jnt.com >> >> >> On 29 July 2010 21:48, John Bruce McCreath >> > wrot= e: >> >> Hello LFers, >> >> I found this while web browsing....interesting >> reading and Mal's favourite mode isn't top dog. >> >> http://kb2hsh.blogspot.com/2010/05/capabilities-of-weak= -signal-digital.html >> >> I was looking for sites having info about digital >> modes on 1,800 kHz. and lower frequencies. >> >> 73, J.B., VE3EAR >> >> LowFER Beacon "EAR" >> 188.830 kHz. QRSS30 >> EN93dr >> >> >> >> >> >> >> > > > > > --=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 --------------070604020504010301040405 Content-Type: text/html; charset=ISO-8859-1 Content-Transfer-Encoding: 7bit Roger, VLF,

I will check the resonance curve in the next experiment. Maybe it is higher than expected due to the high R in that RLC-circuit... So maybe there are even some many Hz available...

Stefan/DK7FC


Am 30.07.2010 09:58, schrieb Roger Lapthorn:
Andy,

Would a variant of WSPR be possible that uses a slower FSK rate over, for example, a 4 minute TX period? Would a half speed WSPR convey the same data in twice as long but only occupy 3Hz bandwidth? This of course assumes K1JT has nothing better to do!

73s
Roger G3XBM

On 30 July 2010 08:54, Roger Lapthorn <rogerlapthorn@gmail.com> wrote:
Presumably "QRSS very very slow" is better still, but here this issue is the time to get data through. Andy, I assume that you're saying WSPR or JT4A give the best "data per bandwidth per given time"?

73s
Roger G3XBM


On 30 July 2010 08:17, Andy Talbot <andy.g4jnt@googlemail.com> wrote:
Try WSPR at 6Hz bandwidth  or JT4A at less that 20Hz.   They are both MSFK constant envelope schemes.
 
2010/7/29 Stefan Schäfer <schaefer@iup.uni-heidelberg.de>

Andy, LF,

Which digital mode could be most suited for a band where one has just an antenna bandwidth of some Hz? You know what i mean... And what could be the "gain" compared to DFCW-600. Gain means here, how far(er) could it be detected, not how much more information can i transmit within the same time.

73, Stefan/DK7FC

PS: I see that e.g. JT65 needs abt 200 Hz, so this NOT suited!


Am 29.07.2010 23:07, schrieb Andy Talbot:
It would be very interesting to see those figures normalised to a constant data rate / bandwidth.  For example, PSK31 shown at -10dB is identical to PKK63 at -7dB - well it would be, its the same modulation, just faster.   Ie plot Bits/second/Hz vs. Eb/No, then stick the Shannon limit on the graph and see which lie nearest.
 
The fact that JT65 is at the top is probably because it sits at around 0.27 chars / second, or something like 1.2 B/s.  Although even after normalisation, it would no doubt still score well up.
 
On 29 July 2010 21:48, John Bruce McCreath <weazle@hurontel.on.ca> wrote:
Hello LFers,

I found this while web browsing....interesting reading and Mal's favourite mode isn't top dog.

http://kb2hsh.blogspot.com/2010/05/capabilities-of-weak-signal-digital.html

I was looking for sites having info about digital modes on 1,800 kHz. and lower frequencies.

73, J.B., VE3EAR

LowFER Beacon "EAR"
188.830 kHz. QRSS30
EN93dr














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