From: Rik Strobbe <Rik.Strobbe@fys.kuleuven.be>
To: "rsgb_lf_group@blacksheep.org" <rsgb_lf_group@blacksheep.org>
Date: Wed, 1 Feb 2012 11:52:30 +0100
Thread-Topic: OPERA and QRS
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References: <4F2911FC.3020709@talktalk.net>
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Subject: LF: RE: OPERA and QRS
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Hello Eddy,

comparing Opera and QRSS with identical bit lengths seems not correct to me=
 as Opera uses "ticks" (such as Forward Error Correction) to improve SNR.
Assuming a simple 8 bit character set it takes only 48 bits to transmit a 6=
 character call. With clever coding (as used in WSPR) it is even possible t=
o fit a 6 character call into 28 bits. But each Opera transmission contains=
 240 bits.
So if Opera is allowed to use FEC in order to improve, QRSS should be allow=
ed to increase dotlength for the same reason.
Same transmission duration seems far more fair than same bit/dot length.=20
But then the dot length would have to differ for every call, so maybe we sh=
ould agree on an "average call" to determine the QRSS dot length. A traditi=
onal method to determine CW speed is the PARIS method (PARIS includes exact=
ly 50 dots, including the word spacing), inserting an average length number=
 (7) would give us the nice call PA7RIS, that contains 66 dots, including t=
he word spacing. As Opera transmits only a single word (call) the word spac=
ing is not used, so it can be ommted also in QRSS what leads to a (convenie=
nt) number of 60 dots.
Opera4 takes 246 seconds, so the QRSS speed to compare with should be 246/6=
0 =3D 4(.096) seconds dot lenght.

73, Rik  ON7YD - OR7T=20

________________________________________
Van: owner-rsgb_lf_group@blacksheep.org [owner-rsgb_lf_group@blacksheep.org=
] namens qrss [qrss@talktalk.net]
Verzonden: woensdag 1 februari 2012 11:20
Aan: rsgb_lf_group@blacksheep.org
Onderwerp: LF: OPERA and QRS

We all seem to have agreed to compare OPERA with a QRS speed which takes
the same time to send a call sign, correct or not?
A QRS beacon can send the call continuously all day and successive
periods are often used to establish the information.

How about comparing like for like in the timing of Data Bits, OPERA uses
digital techniques and no doubt repeats the data in  the 4 minute period
of OP4. In this case we would need to be comparing it with QRS1 or
QRS1.025 if you like.

I feed a coding session coming on.

73 Eddie G3ZJO=