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[Linrad] Re: Perseus with Linrad
- Subject: [Linrad] Re: Perseus with Linrad
- From: yo4aul <arrl.net; yo4aul@xxxxxxxxxxxxxxxx>
- Date: Wed, 2 Jul 2008 09:21:18 -0700 (PDT)
Thanks for comments
> Also noticed that even if in Linrad baseband waterfall the signal was
> still visible, you could not detect the signal audio output by ear...
why is that? Can this signal however be decoded by wsjt software?
Something is wrong with your blanker observations. Otherwise
I think it is correct (but very limited.)
I admit that it is possible that my settings were not optimum
On Jul 2, 5:22 pm, Leif Asbrink <l...@xxxxxxxxxx> wrote:
> Hi Corneliu,
> > I guess that your calibration files for Perseus
> > will be useful to all Perseus owners.
> > I have tested Perseus plus a downconverter 144/28 with a signal
> > generator and a calibrated attenuator with 1 dB steps
> > for MDS and have discovered that Linrad and Winrad main waterfalls are
> > about 10 dB more sensitive than Perseus software.
> There is not really any limit. You can set the bandwith extremely
> narrow in Linrad and average over VERY long times so you can find
> signals that are very much weaker if you wish. That is really the problem
> with Linrad. Any setup I might suggest will be targeted to some
> particular usage and your interest could be something else. That
> is why I do not supply parameters for any particular hardware
> but rather for specific usages.http://www.sm5bsz.com/rf_library.htmhttp://www.sm5bsz.com/linuxdsp/usage/examples.htm
> There are many links here:http://www.sm5bsz.com/linuxdsp/linroot.htm
> Some of them give examples on various usages of Linrad.
> > also noticed that even if in the Perseus main waterfall you could not
> > see anymore the signal, in the extended window the signal was still
> > about 10 db above noise floor.
> This just depends on the parameters you have selected. Linrad allows
> you th have it the other way around in case that is what you want.
> > Also noticed that even if in Linrad baseband waterfall the signal was
> > still visible, you could not detect the signal audio output by ear...
> > I have noticed also that the dumb noiseblanker is quite effective
> > except in the condition when the signal is very close to the noise
> > floor when also the signal gets attenuated by blanker
> That is because you do not use the dumb blanker properly. (I think)
> > I would appreciate if you could supply the Linrad optimized settings
> > for Perseus week signal detection
> There is no such thing. Your local QRM/QRN situation might make
> it optimal to use a different calibration or different sizes
> for transforms. What you mean by weak signal is also a personal
> matter. Chasing weak EME signals is quite different from
> chasing weak SSB bursts in meteor scatter SSB. If you want to work
> weak signals in a terrestrial contest I guess you would not want
> the delay from antenna to loudspeaker to exceed 2 seconds or so.
> (In EME, 10 seconds is fine.)
> I have asked (many times) for recordings of situations where a signal
> is difficult to copy in order to use such examples here:http://www.sm5bsz.com/rf_library.htm
> There are many interesting aspects of interference fighting
> and signal detecting that I would like to demonstrate - but
> I want to do it on real signals not just simulations of mine.
> > Pls also advise if the a.m. findings are correct.
> Something is wrong with your blanker observations. Otherwise
> I think it is correct (but very limited.)
> Leif / SM5BSZ
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