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 to 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 allowed
to increase dotlength for the same reason.
Same transmission duration seems far more fair than same bit/dot length.
But then the dot length would have to differ for every call, so maybe we should
agree on an "average call" to determine the QRSS dot length. A traditional
method to determine CW speed is the PARIS method (PARIS includes exactly 50
dots, including the word spacing), inserting an average length number (7) would
give us the nice call PA7RIS, that contains 66 dots, including the word
spacing. As Opera transmits only a single word (call) the word spacing is not
used, so it can be ommted also in QRSS what leads to a (convenient) number of
60 dots.
Opera4 takes 246 seconds, so the QRSS speed to compare with should be 246/60 =
4(.096) seconds dot lenght.
73, Rik ON7YD - OR7T
________________________________________
Van: [email protected] [[email protected]]
namens qrss [[email protected]]
Verzonden: woensdag 1 februari 2012 11:20
Aan: [email protected]
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
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