Message-ID: <004f01cd6a8c$7566a7c0$0401a8c0@xphd97xgq27nyf>
From: "mal hamilton" <g3kevmal@talktalk.net>
To: <rsgb_lf_group@blacksheep.org>
References: <CAK59VFNOneVPmCEjVc1kK3FpvfmCX5qp_gZo5-AFy58Hmiq-6g@mail.gmail.com> <500FF064.1030109@iup.uni-heidelberg.de> <DEF0879101734958AE61D0D590E070DF@AGB> <500FFDDD.6070204@iup.uni-heidelberg.de> <16CA55FCF4C44B789AA114D2CCB51D1B@AGB>
Date: Wed, 25 Jul 2012 17:39:35 -0000
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Subject: Re: LF: 4X OP32 report
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Graham es Co
While Opera es other data modes are an alternative to CW for a change they
need another level of demodulation and cannot really compete with the basic
CW mode or QRSS CW.
I often see traces of all data modes that could easily be identified in QRSS
but they do not decode therefore the purpose of the transmission is lost.
de mal/g3kev

----- Original Message -----
From: "Graham" <g8fzk@g8fzk.fsnet.co.uk>
To: <rsgb_lf_group@blacksheep.org>
Sent: Wednesday, July 25, 2012 4:07 PM
Subject: Re: LF: 4X OP32 report


> schrieb   Stefan, :)
>
> Why do you think so?
>
> Its linked to the  DSP  engine  in Op , there is a  timing  issue  , if
> other  applications  lock the  sound  card at a  different   rate , due to
> the  % tolerances  , low level  decodes  can be  lost ,   noting, Op is a
> 'data  mode  , so the  overheads in the  transmission  are  much  higher ,
> as are the  DSP  engine  requirements , as can be seen  with  'older' pc's
> cpu loading  can be a  issue , as  is a  one-pass  system , all  the
> processing  is  taking place in real  time
>
> But  on with the  show ,
>
> 73 -G..
>
> -76 dB  in 28  mHz  b/w    , what  is  that  when  translated  to  2.5Khz
> B/w ?
>
>
>
>
> --------------------------------------------------
> From: "Stefan Schäfer" <Stefan.Schaefer@iup.uni-heidelberg.de>
> Sent: Wednesday, July 25, 2012 3:08 PM
> To: <rsgb_lf_group@blacksheep.org>
> Subject: Re: LF: 4X OP32 report
>
> >
> > Am 25.07.2012 15:51, schrieb Graham:
> >>
> >> Pity  nothing decoded  in the  US last night , but  signal 's in 1500
> >> /2000 mile  range where  quite  substantial ...
> >> from this , it seems  that propagation  on 136  is  really  linked to
the
> >> seasons ?
> >
> > Yes (of course) and no. W1VD received me quite well a few weeks ago, see
> > https://dl.dropbox.com/u/19882028/LF/07_July2012.jpg
> > Not to forget W1TAG:
> > https://dl.dropbox.com/u/19882028/LF/DK7FC_Juli2012.jpg
> >
> > So there is some propagation in summer but of course it depends on the
> > solar activity. Don't know how the condx have been yesterday.
> >
> >> One  point  from previous  trials , If  Spec-lab  is  used  with  Opera
> >> , then  SL must  be  set to  48Khz  sample  rate , or  OP can loose
low
> >> level decode sensitivity.
> > Why do you think so? As long as the frequency range of a SSB bandwidth
at
> > audio levels passes through the SL filter, then it should be fine. So 8
> > kHz SR should be fine. Of course it depends on which shift frequency you
> > have to use. I have to use 11 kHz shift and so i choosed a SR of 30 kHz.
> >
> >
> > 73, Stefan
> >
>