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Hi Mike,
I basically support your point of
view.
In my opinion, automatic frequency selection to
what Opera (or any other software) thinks is a clear frequency does not make
much sense on LF. A good human operator would make a careful decision
involving many aspects. For example, he would surely avoid a
known intercontinental beacon frequency (sic!), even if his receiver
cannot currently detect this signal. Or possibly avoid a Japanese
Loran line... For weak signal detections, a posteriori knowledge of your exact
frequency and timing is extremely helpful - what do you do if your
signal has been visible but not decodible, and you can't even tell what QRG
your software has randomly chosen?
Of course you can still select your frequency
manually if you use Opera to key an external oscillator instead of
connecting the audio to an upconverter. But why would you want to enter the
traditional QRSS band, where people like me like to stare into the noise, trying
to decipher bits of human readable code?
Why the need for more spectrum anyway? Opera may
not be overly sensitive, but as Mike has pointed out, it's single frequency and
thus as bandwidth efficient as QRSS. It certainly could put tens of stations
into say just 50 Hz. If you really want to let Opera go DX, it would be better
to adopt something like the TA / Eu split band scheme, and define two
narrow slots with a large gap inbetween.
Regarding DCF39 sidebands, the situation has
worsened here since the advent of their new "dirty" transistor
transmitter. The density of FSK telegrams has increased over the years. In that
respect it would be attractive to center QRSS even lower, and make use
of the spectral gap around 137635 Hz.
BTW If you google for "ros anti jamming" or
similar you may find a past history, where Jose's suggestions for HF band
usage were at least "not undisputed". I would rather not have this kind of
hackling in our narrow and difficult LF band.
That's just my five cents' - I admit it may be a
bit biased, because I didn't like the unclosed coding in the first place.
And I just haven't been convinced of the advantage of using Opera
rather than QRSS/DFCW (human readable), WSPR or MFSK (faster and more
sensitive), Wolf, etc...
Flames invited ;-)
Best 73,
Markus (DF6NM)
Sent: Saturday, March 17, 2012 12:36 PM
Subject: LF: Opera will QRM 137k QRSS
Some of you may have missed my last post on this subject
because it
had 'Opera' in the title and you thought it didn't concern you.
But
it does.
The Opera data mode evolves almost daily and is still in
its Beta
stage. It recommends operating frequencies, and indeed won't work
outside these frequencies without mis-using it. The early versions
recommended 137.3 to 137.5kHz for Opera 8 and 137.5 to 137.6kHz for
the
slower Opera 32, both beacon only. So far, so good.
Just over a week ago,
version 1.3.3 introduced a new 'QSO mode' and
recommended 137.4 to 137.6 for
this activity. It then moved Op8
beacons to 137.6-137.8kHz. My last post on
this subject protested in
strong terms at this flagrant disregard for
long-standing
bandplanning. In particular it would have caused interference
to the
137.777kHz America-Europe DX watering hole.
I have been away
for a week and have downloaded Opera version 1.3.9
(I did say it evolved
daily) and this has improved the bandplanning,
probably thanks to some
members of this group who are closer to the
Opera team than I am.The
threat to the DX wateringhole has gone but
the encroachment on the QRSS
window is still there.
The new frequencies are: 137.5 to 137.6kHz for
Op32 and 137.6 to
137.7kHz for Op8. The 'QSO mode' seems to have been
dropped on this
band.
This still means that Opera 8 beacons will
occupy the area between
137.65 and 137.70 which has for many years been used
for QRSS 3 and
10 QSOs, including the centre frequency (137.70) itself.
Whilst Opera may be regarded as machine generated/read QRSS and
therefore a good bedfellow for QRSS, it uses a different (non-Morse)
coding. Therefore an Opera user will not be able to read QRSS (and
won't
even know it is there it if he turns off the resource-hungry
waterfall
display) and the QRSS user will struggle to read what he
thinks is a weak
QRSS station, but will in fact be Opera.
It could be argued that
QRSS operators could use 137.70 to 136.75kHz,
but this disregards the
substantial QRM from DCF39 sidebands which
affect all of western Europe,
especially Germany. In any case, why
should they have to halve the available
slot?
However, much more to the point, bandplanning on this band has been
the subject of considerable discussion on this group right from the
very
start, and has evolved to suit all concerned. By contrast, the
Opera team
appear to have made arbitrary decisions based perhaps on a
poll of a handful
of keen Opera fans without any consultation with
users of other,
long-standing modes.
When Opera first came out, I was accused of
old-fashioned thinking
when I referrred to local adjacent channel QRM. If
Opera is so
frequency-efficient, why does it need 200Hz when QRSS3/10 has
got by
with 80-100Hz for years?
Lastly, I am not anti-Opera. Until a
week ago I used it every day, on
both modes and regard it as a useful tool.
But it must be compatible
with users of other, well-established,
modes.
Does anyone else feel as angry I do about a software writer
dictating
our bandplans?
Mike,
G3XDV
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