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" <[email protected]>
Sent: Wednesday, February 01, 2012 10:04 AM
To: <[email protected]>
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" <[email protected]>
To: <[email protected]>
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"<[email protected]>
> To:<[email protected]>
> 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
>>
>
>
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