Return-Path: Received: from mtain-df08.r1000.mx.aol.com (mtain-df08.r1000.mx.aol.com [172.29.64.220]) by air-di06.mail.aol.com (v129.4) with ESMTP id MAILINDI063-eacc4c52867a2b2; Fri, 30 Jul 2010 03:59:54 -0400 Received: from post.thorcom.com (post.thorcom.com [193.82.116.20]) by mtain-df08.r1000.mx.aol.com (Internet Inbound) with ESMTP id 94F103800008A; Fri, 30 Jul 2010 03:59:50 -0400 (EDT) Received: from majordom by post.thorcom.com with local (Exim 4.14) id 1OekUb-00055v-4R for rs_out_1@blacksheep.org; Fri, 30 Jul 2010 08:58:57 +0100 Received: from [193.82.116.32] (helo=relay1.thorcom.net) by post.thorcom.com with esmtp (Exim 4.14) id 1OekUa-00055l-II for rsgb_lf_group@blacksheep.org; Fri, 30 Jul 2010 08:58:56 +0100 Received: from mail-bw0-f43.google.com ([209.85.214.43]) by relay1.thorcom.net with esmtp (Exim 4.63) (envelope-from ) id 1OekUX-0005oz-OV for rsgb_lf_group@blacksheep.org; Fri, 30 Jul 2010 08:58:56 +0100 Received: by bwz13 with SMTP id 13so718024bwz.16 for ; Fri, 30 Jul 2010 00:58:52 -0700 (PDT) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=gmail.com; s=gamma; h=domainkey-signature:mime-version:received:received:in-reply-to :references:date:message-id:subject:from:to:content-type; bh=iNd3/NRLy+qV9r5MN/1g9iIFzJeizu3YJWqJ4y47sfE=; b=QM8qUoFfwaVUQnL65dKGbNqBF3oc2Mq+Jf2udoPFVuHGJWpDPKDRG5CQPPgsVlJYOA ihArhMnfLVrPpnwheK2Ozp/ZgHQv6Eg0/BMh1mWWk4RWEnXyURAGoBiniNf3R1xI8tz7 s4MStRuLu56IHgCrMcT6dliMhBofvwBsDYjys= 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=b522TEyP4W7Ghf9xGazCM9yIa99OkvIeyhPenk9mjkIaDKgc9pp2qZv5bC3ucUV01C RdFnoFS0M6iDiD4eUJGNkGfZSr3oqsWPEmJxsTVRfv3MXfcV+XkFGjKOs5az4lB/ubIG vItyToZYJxhKaIYEo2qIMBYOdCoHMVuLFXBTw= MIME-Version: 1.0 Received: by 10.204.34.17 with SMTP id j17mr849142bkd.204.1280476732020; Fri, 30 Jul 2010 00:58:52 -0700 (PDT) Received: by 10.204.122.148 with HTTP; Fri, 30 Jul 2010 00:58:51 -0700 (PDT) In-Reply-To: References: <4C51FA69.1030202@iup.uni-heidelberg.de> Date: Fri, 30 Jul 2010 08:58:51 +0100 Message-ID: From: Roger Lapthorn To: rsgb_lf_group@blacksheep.org DomainKey-Status: good (testing) X-Spam-Score: 0.0 (/) X-Spam-Report: autolearn=disabled,HTML_MESSAGE=0.001 Subject: Re: LF: Digital modes comparison Content-Type: multipart/alternative; boundary=000325557a7ec15915048c9638a5 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-SCOLL-AUTHENTICATION: mail_rly_antispam_dkim-d235.2 ; domain : gmail.com DKIM : pass x-aol-sid: 3039ac1d40dc4c5286766536 X-AOL-IP: 193.82.116.20 X-Mailer: Unknown (No Version) --000325557a7ec15915048c9638a5 Content-Type: text/plain; charset=ISO-8859-1 Content-Transfer-Encoding: quoted-printable 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 dat= a in twice as long but only occupy 3Hz bandwidth? This of course assumes K1J= T 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 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 lim= it 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-digita= l.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 > --=20 http://g3xbm-qrp.blogspot.com/ http://www.g3xbm.co.uk http://www.youtube.com/user/g3xbm G3XBM GQRP 1678 ISWL G11088 --000325557a7ec15915048c9638a5 Content-Type: text/html; charset=ISO-8859-1 Content-Transfer-Encoding: quoted-printable Andy,

Would a variant of WSPR be possible that uses a slower FSK ra= te 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 cou= rse 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 say= ing WSPR or JT4A give the best "data per bandwidth per given time&quo= t;?

73s
Roger G3XBM


On 30 July 2010 08:17, Andy Talbot <= andy.g4jnt@= googlemail.com> wrote:
Try WSPR at 6Hz bandwidth=A0 or JT4A at less that 20Hz.=A0=A0 They ar= e both MSFK constant envelope schemes.
=A0
2010/7/29 Stefan Sch=E4fer &l= t;scha= efer@iup.uni-heidelberg.de>

Andy, LF,

Which digital= mode could be most suited for a band where one has just an antenna bandwi= dth of some Hz? You know what i mean... And what could be the "gain&q= uot; compared to DFCW-600. Gain means here, how far(er) could it be detect= ed, 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:=20
It would be very interesting to see those figures normalised to a con= stant data rate / bandwidth.=A0 For example, PSK31 shown at -10dB is ident= ical to PKK63 at -7dB - well it would be, its the same modulation, just fa= ster.=A0=A0 Ie plot Bits/second/Hz vs. Eb/No, then stick the Shannon limit= on the graph and see which lie nearest.
=A0
The fact that JT65 is at the top is probably because it sits at aroun= d 0.27 chars / second, or something like 1.2 B/s.=A0 Although even after= normalisation, it would no doubt still score=A0well up.
=A0
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/cap= abilities-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











<= div class=3D"h5">--
http://g3xbm-qrp.blogspot.com/
http://www.g3xbm.co.uk
http://www= .youtube.com/user/g3xbm
G3XBM=A0 =A0 GQRP 1678=A0 =A0 =A0 ISWL G11088



--
http://g3xbm-qrp.blogspot.com/
http://www.g3xbm.co.uk
http://www.youtube.com/user/g3xbm G3XBM=A0 =A0 GQRP 1678=A0 =A0 =A0 ISWL G11088
--000325557a7ec15915048c9638a5--