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Date: Wed, 01 Feb 2012 17:59:56 +0000
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Subject: Re: LF: Re: Opera v qrs evaluation
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> not too unexpectedly  , follows the  usual pie  fight 
If you see me joining the fun of the pie fight you know I must be 
feeling better.

> 'you  cannot use  on/off  keying  for a  data  mode'  because .....
It will never work (garden fences spring to mind) that's why no one has 
done it before except for old Sam silly old fool, why didn't I think of 
it grrrr.

E

On 01/02/2012 17:43, Graham wrote:
> Talking of  digging holes , in this case ,   digging  in the noise , 
> the OP32  mode  should provide the best s/n   with  decode possible 
> with  over 50/55% of the  data
>
> Its  possible to  run this  on 500  , just  select  136  and set  the  
> dial frequency  as  500  , the  web -spots will  be showing  136  of  
> course , if your  not  cat  linked , but the  comparison  would  be  
> most valid at the lower end of  the  mode  s/n  ability .. or  on 136  
> where  there  is quite a  lot of  activity using  OP8 , which  is  
> giving quite  reliable  dx decodes . OP4  seems  to  be the  mode  of 
> choice for  500 ,   options  of 2/8 may  be better  suited as the  
> majority  of decodes  (Ed apart !)  are well  inside the  OP2 limits , 
> with  OP8  perhaps  better suited to  dx ... one  for the  'to try 
> list'  , though  development  did take place  with 2/8  on 500.
>
> Better  would  be a high  power  test  on 136 to  see  the  
> difference  of the  systems  at range, but to  date this  has yet to 
> happen...
>
> Mal is  right , its possible  to  have the  signal  showing on the  
> screen , but  no  decode , if over  50/55% of the  data  is lost then, 
> no  decode is  possible, that  is  the  balance  on the  Tx time , 
> too  short  and loose  s/n  . too  long  and qsb  might  remove  too  
> much  data  ..
>
> Keeping a  eye  on the  longer  term  aim of a  'data mode'  the  
> beacon  is providing  useful test  data  and  reliable web linked   
> s/n  measurements, as well  as the seemingly  unlimited opportunity 
> to  rake over the coals  of established 'technical facts' ,
>
> Thanks to  Mal  for  running the  tests  , as perhaps,  not too 
> unexpectedly  , follows the  usual pie  fight , which has produced 
> some useful  analysis, as usual there's  madness  in the method on 
> all  sides ..
>
> Tie  braking  question :)
>
> 'you  cannot use  on/off  keying  for a  data  mode'  because ........
>
> 73 -G..
>
> --------------------------------------------------
> From: "mal hamilton" <g3kevmal@talktalk.net>
> Sent: Wednesday, February 01, 2012 10:04 AM
> To: <rsgb_lf_group@blacksheep.org>
> Subject: Re: LF: Re: Opera v qrs evaluation
>
>> I would say your qrs on 500 was heard/seen but no one could be 
>> bothered to
>> report it.
>> I personally do not report QRS beacon acty on any band.
>> The majority of 500 Beacons are normal CW and I can hear the USA and 
>> Canada
>> frequently and strong enough for a QSO
>> I thought a PIC was an implement to dig a hole with !!
>>
>>
>> ----- Original Message -----
>> From: "qrss" <qrss@talktalk.net>
>> To: <rsgb_lf_group@blacksheep.org>
>> Sent: Wednesday, February 01, 2012 9:29 AM
>> Subject: Re: LF: Re: Opera v qrs evaluation
>>
>>
>>> Mal
>>>
>>> Fact. Everyone including G3KEV has missed my QRS3 and QRS10 on 500kHz
>>> every time I have had it on, using this same TX, in fact I removed the
>>> PIC which sends the QRS and inserted OPERA, viola PA0's at 493km decode
>> me.
>>>
>>> Please be technical not emotional about the subject it doesn't help.
>>>
>>> 73 Eddie
>>>
>>>
>>> On 01/02/2012 09:10, mal hamilton wrote:
>>> > QRSS does NOT get lost or missed  in the noise as you suggest and one
>> can
>>> > always see at least part of the information trace, whereas Opera 
>>> is all
>> or
>>> > nothing and I have noticed at times a TRACE but NO DECODE.
>>> > I wonder what your next distortion of the facts will be
>>> > g3kev
>>> >
>>> > ----- Original Message -----
>>> > From: "qrss"<qrss@talktalk.net>
>>> > To:<rsgb_lf_group@blacksheep.org>
>>> > Sent: Tuesday, January 31, 2012 11:37 PM
>>> > Subject: Re: LF: Re: Opera v qrs evaluation
>>> >
>>> >
>>> >> Dear Jim, Rik, Laurence
>>> >>
>>> >> Thanks for the information, it does seem from all tests that QRS3 
>>> and
>>> >> OP4 are about equivalent.
>>> >> QRS as we know takes a human to notice its there among noise and can
>> get
>>> >> missed. With OPERA (and WSPR) if there is an RX on in range it's
>> de-coded.
>>> >>
>>> >> 73 Eddie G3ZJO
>>> >>
>>> >>
>>> >> On 31/01/2012 22:51, James Moritz wrote:
>>> >>> Dear Eddie, LF Group,
>>> >>>
>>> >>> I did a rough and ready comparative test on the "sensitivity" of 
>>> >>> QRSS3
>>> >>> and Op4 using your back-to-back transmissions. For 500kHz 
>>> reception,
>>> >>> broadband noise from the broadcast stations just east of here is 
>>> >>> being
>>> >>> nulled out using a loop oriented N-S. Rotating the loop out of the
>>> >>> null position gives a convenient way of adjusting the SNR on 
>>> Eddie's
>>> >>> signal. So I increased the noise level until I judged Eddie's 
>>> QRSS >>> was
>>> >>> just fully readable (using 0.3Hz FFT resolution), then left >>> 
>>> everything
>>> >>> in the same position for 4 transmissions, during which signal and
>>> >>> noise levels stayed nearly constant (see the attachment). Opera
>>> >>> reported an SNR of -31dB on Eddie's Op4 signal for all the
>>> > transmissions.
>>> >>> So, from what Graham said, Op4 may have a small margin in SNR with
>>> >>> these conditions. You could argue about what constitutes "readable"
>>> >>> QRSS, but there can't be more than a few dB difference between this
>>> >>> signal and something indecipherable without prior knowledge. It 
>>> takes
>>> >>> 4 minutes to send a callsign using Op4; you could increase the dot
>>> >>> length perhaps to 4s  and transmit most callsigns in 4 minutes, 
>>> which
>>> >>> would gain you about 1.2dB. But for practical purposes I think, in
>>> >>> this test anyway, the two modes are approximately equivalent in 
>>> their
>>> >>> efficiency in sending callsigns.
>>> >>>
>>> >>> Cheers, Jim Moritz
>>> >>> 73 de M0BMU
>>> >>
>>> >
>>> >
>>>
>>>
>>
>>
>
>