Received: from post.thorcom.com (post.thorcom.com [195.171.43.25]) by mtain-md01.r1000.mx.aol.com (Internet Inbound) with ESMTP id 8C7E53800008E; Wed, 24 Aug 2011 18:35:07 -0400 (EDT) Received: from majordom by post.thorcom.com with local (Exim 4.14) id 1QwM1W-0001Bb-79 for rs_out_1@blacksheep.org; Wed, 24 Aug 2011 23:34:14 +0100 Received: from [195.171.43.32] (helo=relay1.thorcom.net) by post.thorcom.com with esmtp (Exim 4.14) id 1QwM1V-0001BS-6R for rsgb_lf_group@blacksheep.org; Wed, 24 Aug 2011 23:34:13 +0100 Received: from relay2.uni-heidelberg.de ([129.206.210.211]) by relay1.thorcom.net with esmtp (Exim 4.63) (envelope-from ) id 1QwM1T-0001yD-L5 for rsgb_lf_group@blacksheep.org; Wed, 24 Aug 2011 23:34:13 +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 p7OMYA1l018635 (version=TLSv1/SSLv3 cipher=DHE-RSA-AES256-SHA bits=256 verify=NO) for ; Thu, 25 Aug 2011 00:34:10 +0200 Received: from [129.206.22.206] (pc206.iup.uni-heidelberg.de [129.206.22.206]) by freitag.iup.uni-heidelberg.de (8.12.11.20060308/8.11.2) with ESMTP id p7OMYALd010563 for ; Thu, 25 Aug 2011 00:34:10 +0200 Message-ID: <4E557B96.2060002@iup.uni-heidelberg.de> Date: Thu, 25 Aug 2011 00:30:46 +0200 From: =?UTF-8?B?U3RlZmFuIFNjaMOkZmVy?= 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: <790E5582101F4A069156B4677843CD78@AGB> <007f01cc6286$0f541490$0401a8c0@xphd97xgq27nyf> <1314211001.22166.YahooMailNeo@web125716.mail.ne1.yahoo.com> <4E55742F.9060103@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: WSPR or QRSS: which is better? Content-Type: multipart/alternative; boundary="------------090308000009000503050503" 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: 0:2:478038208:93952408 X-AOL-SCOLL-URL_COUNT: 0 x-aol-sid: 3039ac1d60554e557c9a792c X-AOL-IP: 195.171.43.25 X-AOL-SPF: domain : blacksheep.org SPF : none This is a multi-part message in MIME format. --------------090308000009000503050503 Content-Type: text/plain; charset=UTF-8; format=flowed Content-Transfer-Encoding: quoted-printable X-MIME-Autoconverted: from 8bit to quoted-printable by relay2.uni-heidelberg.de id p7OMYA1l018635 Hi Roger, Am 25.08.2011 00:21, schrieb Roger Lapthorn: > Yes I agree Stefan. > > I just wanted a clear answer from someone like Andy regarding the=20 > theoretical difference between WSPR (with it's strong error=20 > correction) and QRSS at various speeds. Oh yes, that was the initial question, i remember ;-) > In the limit very slow QRSS is bound to win but WSPR allows a lot of=20 > data to be fed back to the TX station immediately after just a 110sec=20 > burst. ... unless there is a decode at all! Roger, i invite you to leave trace on my grabber in QRSS-60 although=20 this night might not be the most suitable (regarding QRN) ;-) I'm sure you can increase your ODX with a given TX power and antenna=20 configuration. Lastly, do what you like to do! Don't want to convince you to things=20 that appear boring or so. 73, Stefan/DK7FC > > Still to try ROS! > > 73s > Roger G3XBM > > Via my iPod Touch 4g 2.4GHz handheld. > > On 24 Aug 2011, at 22:59, Stefan=20 > Sch=C3=A4fer > wrote: > >> Hello Roger, >> >> OK about WSPR beeing about equal to QRSS-3 in sensitivity. >> >> But if you just want to test how far you can get with your signal,=20 >> why don't you try QRSS-60? This must have an improvement of > 10 dB=20 >> and there are plenty of grabbers running arround your QTH. G4WGT,=20 >> F1AFJ, DK7FC, DF6NM, OE3GHB.... We all are monitoring the band=20 >> sectors all the time. Everybody can read the signals, meaningless if=20 >> QRSS or DFCW or slow hell... You can even have an offset of say 2 Hz=20 >> or a drift of say 1 Hz/hour. The grabbers are running anyway, so you=20 >> don't even have to ask for listening stations if you want to do tests.= .. >> >> Isn't that even simpler and ideal for such tests? >> >> 73, Stefan/DK7FC >> >> Am 24.08.2011 20:56, schrieb Roger Lapthorn: >>> Hi Marcelino >>> >>> Thanks for this. >>> >>> Yes I understand fully what is needed for LF/MF WSPR and have=20 >>> implemented simple and low cost WSPR solutions using transverters=20 >>> for both 136 and 500kHz with some excellent results on the latter=20 >>> band - see my website for details. On=20 >>> 136kHz WSPR my best DX is 148km with a VERY low ERP and simple antenn= a. >>> >>> This autumn I am improving the ERP on both bands and hope to better=20 >>> my DX on WSPR considerably. I also confidently predict that the=20 >>> system improvements will allow me to have my first CW QSO with G3KEV=20 >>> and others on 136kHz. I have already worked him on 500kHz CW with=20 >>> 1mW ERP thanks to his good ears and good system and antennas. >>> >>> 73s >>> Roger G3XBM >>> >>> >>> >>> On 24 August 2011 19:36, Marcelino Garcia >> > wrote: >>> >>> Roger, >>> I fully agree with your statements, but I'm afraid >>> that with a minimalist home made CW transmitter, let's say just >>> a one transistor xtal oscillator, it's not possible to use >>> WSPR, for this mode a little more complex transmitter, may be >>> SDR based, should be used. >>> 73, >>> Marcelino - LU7DSU >>> >>> -----------------------------------------------------------------= ------- >>> *De:* Roger Lapthorn >> > >>> *Para:* rsgb_lf_group@blacksheep.org >>> >>> *Enviado:* mi=C3=A9rcoles, 24 de agosto de 2011 15:18 >>> *Asunto:* Re: LF: WSPR or QRSS: which is better? >>> >>> Mal >>> >>> Thanks again for your comments, some of which are valid. >>> >>> There are times when CW is useful and times when more efficient >>> modes like WSPR really win out. >>> >>> As I have said countless times now, no other mode apart from >>> WSPR that I know of is able to give me almost instant feedback >>> (via the internet database) at a distance that (a) my signal is >>> being received at all, (b) how far it is getting, and (c) how >>> strong it is. To be able to get this information when using >>> simple, low powered and home made equipment is extremely useful. >>> A small change in the PA output or antenna efficiency is >>> measurable. >>> >>> It really comes down to what is the purpose of our experiments: >>> being able to make CW contacts is a perfectly reasonable aim - >>> please carry on. In my case it is to see just what is possible >>> with minimalist (hardware) equipment on the VLF, LF and MF >>> bands. Yes, I am gaining valuable dBs by the use of efficient >>> coding systems and clever PC software, but I see nothing wrong >>> in that. >>> >>> And finally, please do NOT call me an appliance operator: all my >>> VLF-MF equipment is home-made as is much of my HF and VHF gear. >>> I am happy to use modern technology to enhance my enjoyment of >>> the hobby and to exploit weak signal modes but I am equally >>> happy to have a CW QSO on any band when the opportunity arises. >>> >>> 73s >>> Roger G3XBM >>> >>> >>> >>> On 24 August 2011 18:48, mal hamilton >> > wrote: >>> >>> Jim take NOTE >>> Impulsive noise generates a random output that looks like a >>> valid callsign so this is also inventing a signal that you >>> imagine to exist. >>> An immediate positive ID, don't depend on it !! >>> An appliance communications operator is easily hoodwinked. >>> Bletchley Park CW expert Radio Operators managed to piece >>> messages together and achieved the object., and no doubt >>> used imagination. >>> No expertise is need to send/receive wspr and for that >>> matter a lot of other appliance operator modes, know in the >>> services today as IDIOT PROOF comms black boxes. >>> For a commercial operator that needs to shift thousands of >>> messages worldwide then automated digital modes are >>> necessary and useful, but for a radio hobbyist its like >>> using a sledge hammer to crack the proverbial nut >>> g3kev >>> Original Message ----- >>> >>> *From:* Andy Talbot >>> *To:* rsgb_lf_group@blacksheep.org >>> >>> *Sent:* Wednesday, August 24, 2011 6:06 PM >>> *Subject:* Re: LF: WSPR or QRSS: which is better? >>> >>> I know what you're referring to. In cases of impulsive >>> noise, there is a finite probability of something >>> eventually getting through the decoder and being >>> flagged as valid. The very nature of heavy source >>> coding, means that the resulting random output will look >>> like a valid callsign. However, WE then apply the next >>> level of error detection, by knowing the combination >>> must be rubbish. >>> 'jnt [and there is another example of source coding] >>> >>> >>> On 24 August 2011 17:47, Graham >> > wrote: >>> >>> >> and gives absolutely guaranteed error free >>> decoding, or nothing at all. << >>> Are you sure ? >>> G.. >>> >>> *From:* Andy Talbot >>> *Sent:* Wednesday, August 24, 2011 5:12 PM >>> *To:* rsgb_lf_group@blacksheep.org >>> >>> *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. =20 >>> Dot speed =3D WPM / 1.2) If we have 2s dots, that i= s >>> 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.=20 >>> 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/ >>> >>> >>> >>> >>> >>> >>> >>> >>> --=20 >>> http://g3xbm-qrp.blogspot.com/ >>> http://www.g3xbm.co.uk >>> http://www.youtube.com/user/g3xbm >>> https://sites.google.com/site/sub9khz/ >>> >>> >>> >>> >>> >>> >>> --=20 >>> http://g3xbm-qrp.blogspot.com/ >>> http://www.g3xbm.co.uk >>> http://www.youtube.com/user/g3xbm >>> https://sites.google.com/site/sub9khz/ >>> --------------090308000009000503050503 Content-Type: text/html; charset=UTF-8 Content-Transfer-Encoding: quoted-printable X-MIME-Autoconverted: from 8bit to quoted-printable by relay2.uni-heidelberg.de id p7OMYA1l018635 Hi Roger,

Am 25.08.2011 00:21, schrieb Roger Lapthorn:
Yes I agree Stefan.=C2=A0

I just wanted a clear answer from someone like Andy regarding the theoretical difference between WSPR (with it's strong error correction) and QRSS at various speeds.
Oh yes, that was the initial question, i remember ;-)

In the limit very slow QRSS is bound to win but WSPR allows a lot of data to be fed back to the TX station immediately after just a 110sec burst.
... unless there is a decode at all!

Roger, i invite you to leave trace on my grabber in QRSS-60 although this night might not be the most suitable (regarding QRN) ;-)
I'm sure you can increase your ODX with a given TX power and antenna configuration.
Lastly, do what you like to do! Don't want to convince you to things that appear boring or so.

73, Stefan/DK7FC


Still to try ROS!

73s
Roger G3XBM

Via my iPod Touch 4g 2.4GHz handheld.=C2=A0

On 24 Aug 2011, at 22:59, Stefan Sch=C3=A4fer<Stefan.Schaefer@iu= p.uni-heidelberg.de> wrote:

Hello Roger,

OK about WSPR beeing about equal to QRSS-3 in sensitivity.

But if you just want to test how far you can get with your signal, why don't you try QRSS-60? This must have an improvement of > 10 dB and there are plenty of grabbers running arround your QTH. G4WGT, F1AFJ, DK7FC, DF6NM, OE3GHB.... We all are monitoring the band sectors all the time. Everybody can read the signals, meaningless if QRSS or DFCW or slow hell... You can even have an offset of say 2 Hz or a drift of say 1 Hz/hour. The grabbers are running anyway, so you don't even have to ask for listening stations if you want to do tests...

Isn't that even simpler and ideal for such tests?

73, Stefan/DK7FC

Am 24.08.2011 20:56, schrieb Roger Lapthorn:
Hi Marcelino

Thanks for this.

Yes I understand fully what is needed for LF/MF WSPR and have implemented simple and low cost WSPR solutions using transverters for both 136 and 500kHz with some excellent results on the latter band - see my websit= e for details. On 136kHz WSPR my best DX is 148km with a VERY low ERP and simple antenna.

This autumn I am improving the ERP on both bands and hope to better my DX on WSPR considerably. I also confidently predict that the system improvements will allow me to have my first CW QSO with G3KEV and others on 136kHz. I have already worked him on 500kHz CW with 1mW ERP thanks to his good ears and good system and antennas.

73s
Roger G3XBM



On 24 August 2011 19:36, Marcelino Garcia <lu7dsu@yahoo.com.ar> wrote:
Roger,
=C2=A0=C2=A0=C2=A0=C2=A0=C2=A0=C2=A0=C2=A0=C2=A0=C2=A0= =C2=A0=C2=A0 I fully agree with your statements, but I'm afraid that with a minimalist home made CW transmitter, let's say just a one transistor xtal oscillator, it's not=C2=A0 possible to use WSPR, fo= r this mode a little more complex transmitter, may be SDR based, should be used.
73,
Marcelino - LU7DSU

De: Roger Lapthorn <rogerlapthorn@gmail.com><= br> Para: rs= gb_lf_group@blacksheep.org
Enviado: mi=C3=A9rcoles, 24 de agosto de 2011 15:18
Asunto: Re: LF: WSPR or QRSS: which is better?

Mal

Thanks again for your comments, some of which are valid.=C2=A0

There are times when CW is useful and times when more efficient modes like WSPR really win out.

As I have said countless times now, no other mode apart from WSPR that I know of is able to give me almost instant feedback (via the internet database) at a distance that (a) my signal is being received at all, (b) how far it is getting, and (c) how strong it is. To be able to get this information when using simple, low powered and home made equipment is extremely useful. A small change in the PA output or antenna efficiency is measurable.

It really comes down to what is the purpose of our experiments: being able to make CW contacts is a perfectly reasonable aim - please carry on. In my case it is to see just what is possible with minimalist (hardware) equipment on the VLF, LF and MF bands. Yes, I am gaining valuable dBs by the use of efficient coding systems and clever PC software, but I see nothing wrong in that.

And finally, please do NOT call me an appliance operator: all my VLF-MF equipment is home-made as is much of my HF and VHF gear. I am happy to use modern technology to enhance my enjoyment of the hobby and to exploit weak signal modes but I am equally happy to have a CW QSO on any band when the opportunity arises.

73s
Roger G3XBM



On 24 August 2011 18:48, mal hamilton <= g3kevmal@= talktalk.net> wrote:
Jim take NOTE
Impulsive noise generates a random output that looks like a valid callsign so this is also=C2=A0inventing a signal that you imagine to exist.
An immediate positive ID, don't depend on it !!
An appliance communications operator is easily hoodwinked.
Bletchley Park CW=C2=A0=C2=A0expert R= adio Operators managed to piece messages together and achieved the object., and no doubt used imagination.
No expertise is need to send/receive wspr and for that matter a lot of other appliance operator modes, know in the services today as IDIOT PROOF comms black=C2=A0boxes.
For a commercial operator that needs to shift thousands of messages worldwide then automated digital modes are necessary and useful, but for a radio hobbyist its like using a sledge hammer to crack the proverbial nut
=C2=A0
g3kev
=C2=A0
=C2=A0
=C2=A0
=C2=A0
=C2=A0Original Message -----
Sent: Wednesday, August 24, 2011 6:06 PM
Subject: Re: LF: WSPR or QRSS: which is better?

I know what you're referring to.=C2=A0 In cases of impulsive noise, there is a finite=C2=A0probability of=C2=A0something eventually =C2= =A0getting through the decoder and being flagged as valid.=C2=A0 The very nature of heavy source coding, means that the resulting random output will look like a valid callsign.=C2=A0=C2=A0 However, WE then apply the next level = of error detection, by knowing the combination must be rubbish.
=C2=A0
'jnt=C2=A0=C2=A0 [and there is another=C2=A0example of s= ource coding]


=C2=A0
On 24 August 2011 17:47, Graham <g8fzk@g= 8fzk.fsnet.co.uk> wrote:
>>=C2=A0 and gives absolutely guaranteed error f= ree decoding, or nothing at all.=C2=A0 <<
=C2=A0
Are you sure ?=C2=A0
=C2=A0
G..

From: Andy Talbot <= /div>
Sent: Wednesday, August 24, 2011 5:12 PM
Subject: Re: LF: WSPR or QRSS: which is better?

WSPR works=C2=A0in a 1.46Hz signal bandwidth and becau= se of its very high level of error correction and soft-decision decoding, means that=C2=A0it will work at a S/N of about 3dB in this bandwidth, and sometimes a bit lower still=C2=A0 (Normally, FSK with no correction at all=C2=A0needs about 10 - 12dB S/N for near error-free performance)
=C2=A0
QRSS=C2=A0has 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.=C2=A0 (A for= m of forward error correction is now in use here as well perhaps=C2=A0:-)=C2= =A0 So lets say 5dB S/N is a working value..
=C2=A0
So take=C2=A03dB in 1.46Hz=C2=A0as a starting point an= d derive the bandwidth for QRSS needed to get 5dB S/N with the same signal.=C2=A0 This will have to be narrower to get a 2dB higher S/N and works out as 1.46=C2=A0/ 10^(2/10) =3D 0.92Hz
=C2=A0
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.=C2=A0=C2=A0 Which is probably the info you wanted.
=C2=A0
But now compare source coding efficiencies.=C2=A0=C2=A0= WSPR fits a callsign, locator and power level into a 110 second transmission - and gives absolutely guaranteed error free decoding, or nothing at all.=C2=A0=C2=A0About 12 characters in actuality, but that is being a bit= unfair as the coding forces certain callsign and locator formatting.=C2=A0=C2=A0= So in all probablility, more like 7 or 8 effective characters (I'm being a bit empirical here)
=C2=A0
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.=C2=A0=C2=A0=C2=A0 Dot speed =3D WPM / 1.2) =C2=A0 If we= have 2s dots, that is 5 characters can be sent=C2=A0in the time for a WSPR transmission.
=C2=A0
So as a quick estimate, WSPR wins by=C2=A0roughly 2dB = in S/N terms for a given dot period / noise bandwidth.=C2=A0 And at similar S/N values, WSPR is about 1.5 times faster
Andy
=C2=A0
=C2=A0
=C2=A0
=C2=A0
On 24 August 2011 16:42, Roger Lapthorn <rogerlapthorn@gmail.com><= /span> 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

--
http://g3xbm-qrp.blogspot.com/
http://www.g3xbm.co.uk
http://www.youtube.com/user/g= 3xbm
https://sites.google.com= /site/sub9khz/








--
http://g3xbm-qrp.blogspot.com/
http:= //www.g3xbm.co.uk
http://www.youtube.com/user/g= 3xbm
https://sites.google.com= /site/sub9khz/






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

--------------090308000009000503050503--