On 8 February 2012 20:17, Roger Lapthorn <
[email protected]> wrote:
> Rik's comment that WSPR is roughly equivalent to QRSS10 is interesting and
> ties up well with my own experience: with QRPp and a small antenna QRSS3 was
> a struggle (100km) , QRSS30 got me a decent distance (300km +) and WSPR got
> me somewhere in the middle (250km) .
>
> It still surprises me that more people don't use WSPR on 136kHz for
> beaconing when it is stable, reliable, very well documented and has all the
> advantages of an internet database to almost instantly check how well your
> signal is being propagated. I guess the disadvantages are the need for a
> linear PA and the timing accuracy. I've still not re-installed OPERA as I
> know it would be a CPU struggle with my PC.
>
> 73s
> Roger G3XBM
>
>
>
> On 8 February 2012 18:32, James Moritz <
[email protected]> wrote:
>>
>> Dear Andy, Rik, LF Group,
>>
>>
>> G4JNT wrote:
>> ...>When you generasted the Opera and WSPR audio files, did you take into
>> account that Opera should be compared using the mean power? With its
>> 50% duty cycle, this means an Opera Tx has to have twice the power
>> rating of one running WSPR for equal S/N ratios...>
>>
>> ... But on the other hand, you could argue that since the TX power is in
>> practice normally limited by the PEP available from the PA. So by having
>> 100% duty cycle, WSPR effectively doubles the available average output power
>> from a given transmitter, compared to Opera. I suppose it depends whether
>> you are more worried about corona on the antenna, or your electricity bill
>> ;-)
>>
>> I think it is interesting that there is only a small difference between
>> "average" and "top 10" operators - down to about 70% correct copy, there
>> appears be less than 1dB between "good" and "average". Surely any lower
>> levels of accuracy would be pretty useless for communicating information,
>> even in an amateur context. This suggests the "human factor" in QRSS
>> reception is perhaps quite a small factor.
>>
>> Cheers, Jim Moritz
>> 73 de M0BMU
>>
>>
>>
>>
>>
>>
>>
>>
>>
>> If you used peak power (ie. the same transmitter amplitude), the curve
>> plotted for Opera will have to move 3dB to the right, making it more
>> comparable with WSPR - and then more as one would expect.
>>
>> Given the similarity of the error correction overhead for Opera and
>> WSPR, and nearly matching symbol rate for OP2 ,and that OOK and FSK
>> have comparable error rates for the same mean power, suggests the two
>> modes should give roughly similar performance.
>>
>> Only 27 responses, that doesn't seem very many compared with the
>> numbers that monitor this reflector.
>>
>> Andy G4JNT
>>
>>
>> On 8 February 2012 16:00, Rik Strobbe <
[email protected]> wrote:
>>>
>>> Dear all,
>>>
>>> the results of the "QRSS3 challenge" can be found at
>>>
http://on7yd.strobbe.eu/QRSS/
>>> Hit refresh if you still see the old challenge.
>>>
>>> Thanks to all who participated !
>>>
>>> 73, Rik ON7YD - OR7T
>>>
>>> ________________________________
>>> Van: Rik Strobbe
>>> Verzonden: donderdag 2 februari 2012 18:17
>>> Aan:
[email protected]
>>> Onderwerp: QRSS3 "challenge"
>>>
>>> Dear all,
>>>
>>>
>>>
>>> as mentioned some days ago I generated a whole series of Opera, WSPR
>>> and QRSS3 audio with a known SNR.
>>>
>>> For Opera and WSPR it was easy to determine the lowest SNR for a proper
>>> decode. But for QRSS3 it is much more difficult as it depends on the
>>> operators "sharp eye". It must be somewhere in the range of -24 to -28dB
>>> SNR
>>> (@ 2.5kHz BW).
>>>
>>> Today I did put all the QRSS3 screenshots in this range in a
>>> website, where you can fill in what you see (decode) for each screenshot.
>>>
>>> I would like to invite all of you to give it a try and send me the
>>> results
>>> (the more entries the better the statistics).
>>>
>>> After some time (Feb 10th) will put all results into some nice tables
>>> and graphs and make them available.
>>>
>>> Of course no personal (individual) results will be published. But based
>>> on
>>> the results every participant (who keeps his results) can see where he
>>> ends.
>>>
>>>
>>>
>>> The "QRSS3 Challenge" can be found at
http://on7yd.strobbe.eu/QRSS/
>>>
>>>
>>>
>>> 73, Rik ON7YD - OR7T
>>
>>
>>
>>
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>>
>>
>
>
>
> --
>
http://qss2.blogspot.com/
>
http://g3xbm-qrp.blogspot.com/
>
http://www.g3xbm.co.uk
>
https://sites.google.com/site/sub9khz/
>
>
