Received: from post.thorcom.com (post.thorcom.com [195.171.43.25]) by mtain-mc05.r1000.mx.aol.com (Internet Inbound) with ESMTP id 08E3D380000B5; Wed, 24 Aug 2011 12:55:44 -0400 (EDT) Received: from majordom by post.thorcom.com with local (Exim 4.14) id 1QwGjB-0007XO-VM for rs_out_1@blacksheep.org; Wed, 24 Aug 2011 17:54:57 +0100 Received: from [195.171.43.32] (helo=relay1.thorcom.net) by post.thorcom.com with esmtp (Exim 4.14) id 1QwGjB-0007XE-Az for rsgb_lf_group@blacksheep.org; Wed, 24 Aug 2011 17:54:57 +0100 Received: from out1.ip08ir2.opaltelecom.net ([62.24.128.244]) by relay1.thorcom.net with esmtp (Exim 4.63) (envelope-from ) id 1QwGj8-00040z-09 for rsgb_lf_group@blacksheep.org; Wed, 24 Aug 2011 17:54:57 +0100 X-IronPort-Anti-Spam-Filtered: true X-IronPort-Anti-Spam-Result: ArsAAN4rVU5cHnUG/2dsb2JhbABClBYDhAWPWHiBOQIFAQEFCAEBAzwNAhMZAQEDBQIBAxEEAQEKJRQBBAgSBhYIBhMKAQICAQGHYgK7MYZJBIJRhGGVXocF X-IronPort-AV: E=Sophos;i="4.68,276,1312153200"; d="scan'208,217";a="499917993" Received: from host-92-30-117-6.as13285.net (HELO xphd97xgq27nyf) ([92.30.117.6]) by out1.ip08ir2.opaltelecom.net with SMTP; 24 Aug 2011 17:54:47 +0100 Message-ID: <004e01cc627e$87afaba0$0401a8c0@xphd97xgq27nyf> From: "mal hamilton" To: References: <003e01cc627a$9bde96d0$0401a8c0@xphd97xgq27nyf> Date: Wed, 24 Aug 2011 17:54:46 +0100 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: 0.0 (/) X-Spam-Report: autolearn=disabled,HTML_MESSAGE=0.001 Subject: Re: LF: WSPR or QRSS: which is better? Content-Type: multipart/alternative; boundary="----=_NextPart_000_004B_01CC6286.E92EF450" X-Spam-Checker-Version: SpamAssassin 2.63 (2004-01-11) on post.thorcom.com X-Spam-Level: X-Spam-Status: No, hits=0.6 required=5.0 tests=HTML_20_30, 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-SCOLL-SCORE: 0:2:471138752:93952408 X-AOL-SCOLL-URL_COUNT: 0 x-aol-sid: 3039ac1d604d4e552d107dd3 X-AOL-IP: 195.171.43.25 X-AOL-SPF: domain : blacksheep.org SPF : none This is a multi-part message in MIME format. ------=_NextPart_000_004B_01CC6286.E92EF450 Content-Type: text/plain; charset="iso-8859-1" Content-Transfer-Encoding: quoted-printable In the radio amateur context of course you know what you are expecting = for a basic QSO, at least you are getting something meaningful whereas = with wspr like you say you get nothing, hard to fill gaps with NOTHING. and DFCW again with only one level of modulation is a better mode than = wspr I know it is hard to convince an Appliance Operator otherwise!!!!!!!!!! g3kev ----- Original Message -----=20 From: Andy Talbot=20 To: rsgb_lf_group@blacksheep.org=20 Sent: Wednesday, August 24, 2011 5:37 PM Subject: Re: LF: WSPR or QRSS: which is better? You can only fill in the gaps if you know what you're expecting. --------- --- --------- --- --- --- --- --------- = or --- --- --- --------- ------ --------- --------- KEV turns into a sort-of VTM with a few dot symbols in error (view using a fixed width font) DFCW would be a far better solutino 'jnt =20 On 24 August 2011 17:26, mal hamilton wrote: Like the man says either you get something or NOTHING which is often = the case, whereas with QRS you always get SOMETHING and since all radio = amateurs are competent with morse code and where there is fade or drop out you can fill the gaps, not the case with = wspr or the other data modes, and like I said already with poor un = decodeable wspr had the transmission been in QRS a messages could be = exchanged. g3kev ----- Original Message -----=20 From: Andy Talbot=20 To: rsgb_lf_group@blacksheep.org=20 Sent: Wednesday, August 24, 2011 5:12 PM Subject: Re: LF: WSPR or QRSS: which is better? WSPR works in a 1.46Hz signal bandwidth and because of its very = high level of error correction and soft-decision decoding, means that it = will work at a S/N of about 3dB in this bandwidth, and sometimes a bit = lower still (Normally, FSK with no correction at all needs about 10 - = 12dB S/N for near error-free performance) QRSS has to show about 6 - 10dB in its signal bandwidth to be able = to discern fully what is sent, although a slightly lower S/N may be = useable when you 'know' what you should be receiving. (A form of = forward error correction is now in use here as well perhaps :-) So lets = say 5dB S/N is a working value.. So take 3dB in 1.46Hz as a starting point and derive the bandwidth = for QRSS needed to get 5dB S/N with the same signal. This will have to = be narrower to get a 2dB higher S/N and works out as 1.46 / 10^(2/10) = =3D 0.92Hz So QRSS used with a 0.9Hz bandwidth - which I think means about a = 2 - 3s dot period ought to be decoded at the same S/N as a WSPR signal. = Which is probably the info you wanted. But now compare source coding efficiencies. WSPR fits a = callsign, locator and power level into a 110 second transmission - and = gives absolutely guaranteed error free decoding, or nothing at all. = About 12 characters in actuality, but that is being a bit unfair as the = coding forces certain callsign and locator formatting. So in all = probablility, more like 7 or 8 effective characters (I'm being a bit = empirical here) Assuming standard QRSS - not DFCW - , which if like standard = Morse, then 5 characters takes about 50 dot symbols to send (12WPM =3D = 60 chars in 1 minute, =3D 1 char / second, or about 10 dot periods / = second. Dot speed =3D WPM / 1.2) If we have 2s dots, that is 5 = characters can be sent in the time for a WSPR transmission. So as a quick estimate, WSPR wins by roughly 2dB in S/N terms for = a given dot period / noise bandwidth. And at similar S/N values, WSPR = is about 1.5 times faster Andy www.g4jnt.com On 24 August 2011 16:42, Roger Lapthorn = wrote: A question for the coding experts here: WSPR is an excellent = weak signal beaconing mode, but at what QRSS speed is QRSS "better" ? 73s Roger G3XBM --=20 http://g3xbm-qrp.blogspot.com/ http://www.g3xbm.co.uk http://www.youtube.com/user/g3xbm https://sites.google.com/site/sub9khz/ ------=_NextPart_000_004B_01CC6286.E92EF450 Content-Type: text/html; charset="iso-8859-1" Content-Transfer-Encoding: quoted-printable
In the radio amateur context of course you know = what you=20 are expecting for a basic QSO, at least you are getting something = meaningful=20 whereas with wspr like you say you get nothing, hard to fill gaps with=20 NOTHING.
and DFCW again with only one level of modulation = is a=20 better mode than wspr
I know it is hard to convince an Appliance = Operator=20 otherwise!!!!!!!!!!
g3kev
 
 
----- Original Message -----
From:=20 Andy=20 Talbot
Sent: Wednesday, August 24, = 2011 5:37=20 PM
Subject: Re: LF: WSPR or QRSS: = which is=20 better?

You can only fill in the gaps if you know what you're = expecting.
---------   ---  =20 ---------        =20 ---         ---  --- ---=20 ---------   or
---   ---   ---  =20 ---------        =20 ------      ---------   =20 ---------
 
KEV turns into a sort-of  VTM   with a few dot = symbols in=20 error
 
(view using a fixed width font)
 
DFCW would be a far better solutino
 
'jnt
          =

On 24 August 2011 17:26, mal hamilton <g3kevmal@talktalk.net>=20 wrote:
Like the man says either you get something = or NOTHING=20 which is often the case, whereas with QRS you always get SOMETHING = and since=20 all radio amateurs are competent with morse code and = where
 there is fade or drop out you can fill = the gaps,=20 not the case with wspr or the other data modes, and like I said = already with=20 poor un decodeable wspr had the transmission been in QRS a messages = could be=20 exchanged.
g3kev
 
 
----- Original Message ----- =
From: = Andy Talbot
To: rsgb_lf_group@blacksheep.org
Sent: Wednesday, August 24, = 2011 5:12=20 PM
Subject: Re: LF: WSPR or = QRSS: which=20 is better?

WSPR works in a 1.46Hz signal bandwidth and because of = its very=20 high level of error correction and soft-decision decoding, means=20 that it will work at a S/N of about 3dB in this bandwidth, = and=20 sometimes a bit lower still  (Normally, FSK with no = correction at=20 all needs about 10 - 12dB S/N for near error-free = performance)
 
QRSS has to show about 6 - 10dB in its signal bandwidth = to be=20 able to discern fully what is sent, although a slightly lower S/N = may be=20 useable when you 'know' what you should be receiving.  (A = form of=20 forward error correction is now in use here as well = perhaps :-) =20 So lets say 5dB S/N is a working value..
 
So take 3dB in 1.46Hz as a starting point and = derive the=20 bandwidth for QRSS needed to get 5dB S/N with the same = signal.  This=20 will have to be narrower to get a 2dB higher S/N and works out as=20 1.46 / 10^(2/10) =3D 0.92Hz
 
So QRSS used with a 0.9Hz bandwidth - which I think means = about a 2 -=20 3s dot period ought to be decoded at the same S/N as a WSPR=20 signal.   Which is probably the info you wanted.
 
But now compare source coding efficiencies.   WSPR = fits a=20 callsign, locator and power level into a 110 second transmission - = and=20 gives absolutely guaranteed error free decoding, or nothing at=20 all.  About 12 characters in actuality, but that is = being a bit=20 unfair as the coding forces certain callsign and locator=20 formatting.   So in all probablility, more like 7 or 8 = effective=20 characters (I'm being a bit empirical here)
 
Assuming standard QRSS - not DFCW - , which if like standard = Morse,=20 then 5 characters takes about 50 dot symbols to send (12WPM =3D 60 = chars in=20 1 minute, =3D 1 char / second, or about 10 dot periods /=20 second.    Dot speed =3D WPM / 1.2)   If we = have 2s=20 dots, that is 5 characters can be sent in the time for a WSPR = transmission.
 
So as a quick estimate, WSPR wins by roughly 2dB in S/N = terms=20 for a given dot period / noise bandwidth.  And at similar S/N = values,=20 WSPR is about 1.5 times faster
Andy
 
 
 
 
On 24 August 2011 16:42, Roger Lapthorn = <rogerlapthorn@gmail.com> wrote:
A=20 question for the coding experts here: WSPR is an excellent weak = signal=20 beaconing mode, but at what QRSS speed is QRSS "better"=20 ?

73s
Roger G3XBM

--=20
http://g3xbm-qrp.blogspot.com/
http://www.g3xbm.co.uk
http://www.youtube.com/user/g3xbm
https://sites.google.com/site/sub9khz/

=

=
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