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Re: [perseus_SDR] Re: Perseus Vs AR7030

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  • Tracey Gardner
    Hello Alex Agreed, but how much nicer to have the Perseus software provide the selectivity. I m used to listening with the 20Hz xtal filters in my selective
    Message 1 of 23 , Mar 2, 2008
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      Hello Alex

      Agreed, but how much nicer to have the Perseus software provide the
      selectivity.
      I'm used to listening with the 20Hz xtal filters in my selective level
      meters and then through a 6/7Hz bandwidth audio filter.
      I am hoping that Nico will eventually look at esoteric requests like mine
      :-)

      73s Tracey

      ----- Original Message -----
      From: "Alex Crow" <alex@...>
      To: <perseus_SDR@yahoogroups.com>
      Sent: Sunday, March 02, 2008 12:28 PM
      Subject: Re: [perseus_SDR] Re: Perseus Vs AR7030


      > Tracey,
      >
      > You could always feed the Perseus output into Spectrum Labs or the
      > like...
      >
      > I have VAC installed but I'm not sure if it's actually being used for
      > this. I just mute the Perseus (button above the Vol slider) and launch
      > whatever program and I seems to work OK.
      >
      > Cheers
      >
      > Alex
      >
      >
      > On Sun, 2008-03-02 at 12:17 +0000, Tracey Gardner wrote:
      >> Hello Martin
      >>
      >> 75Hz selectivity is like a barn door for my interests :-)
      >>
      >> Cheers
      >>
      >> Tracey
      >>
      >> ----- Original Message -----
      >> From: "Martin Elbe" <elbe@...>
      >> To: <perseus_SDR@yahoogroups.com>
      >> Sent: Sunday, March 02, 2008 12:13 PM
      >> Subject: Re: [perseus_SDR] Re: Perseus Vs AR7030
      >>
      >> Am 02.03.2008 um 12:28 schrieb John Faulkner:
      >>
      >> > I will probably be ordering my Perseus in the next week or two.
      >>
      >> A very wise decision, you won't regret.
      >> Concerning your question on filters: You can go down to 75 Hertz.
      >>
      >> --
      >> Tschüß,
      >> Martin http://home.wolfsburg.de/elbe/
      >>
      >> Yahoo! Groups Links
      >>
      >> --
      >> No virus found in this incoming message.
      >> Checked by AVG Free Edition.
      >> Version: 7.5.516 / Virus Database: 269.21.3/1306 - Release Date:
      >> 01/03/2008
      >> 17:41
      >>
      >>
      >>
      >>
      >>
      >
      >
      >
      >
      > Yahoo! Groups Links
      >
      >
      >
      >
      >
      > --
      > No virus found in this incoming message.
      > Checked by AVG Free Edition.
      > Version: 7.5.516 / Virus Database: 269.21.3/1306 - Release Date:
      > 01/03/2008 17:41
      >
      >
    • schiffhauer.nils
      Tracey - for what purposes you use those very small bandwidths? I do also need small bandwidths, sometimes in the millihertz-range, to enhance the
      Message 2 of 23 , Mar 2, 2008
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        Tracey - for what purposes you use those very small bandwidths? I do
        also need small bandwidths, sometimes in the millihertz-range, to
        enhance the signal/noise-ratio & to resolve "co-channel"-stations
        differing a fraction of a hertz. So for me, small bandwidths mean
        great resolution (also to show doppler-effects, and x-/o-rays). But I
        don't have/want to listen at these bandwidths, I am using them in
        audio analyzing software like SBSpectrum.
        Maybe the extraordinary in-band dynamic range and the pure oscillator
        of Perseus will make your wishing such small bandwidths superfluous?
        73 Nils, DK8OK

        --- In perseus_SDR@yahoogroups.com, "Tracey Gardner"
        <tracey.gardner@...> wrote:
        >
        > Hello Martin
        >
        > 75Hz selectivity is like a barn door for my interests :-)
        >
        > Cheers
        >
        > Tracey
        >
        > ----- Original Message -----
        > From: "Martin Elbe" <elbe@...>
        > To: <perseus_SDR@yahoogroups.com>
        > Sent: Sunday, March 02, 2008 12:13 PM
        > Subject: Re: [perseus_SDR] Re: Perseus Vs AR7030
        >
        >
        >
        > Am 02.03.2008 um 12:28 schrieb John Faulkner:
        >
        > > I will probably be ordering my Perseus in the next week or two.
        >
        > A very wise decision, you won't regret.
        > Concerning your question on filters: You can go down to 75 Hertz.
        >
        > --
        > Tschüß,
        > Martin http://home.wolfsburg.de/elbe/
        >
        >
        >
        >
        > Yahoo! Groups Links
        >
        >
        >
        >
        >
        > --
        > No virus found in this incoming message.
        > Checked by AVG Free Edition.
        > Version: 7.5.516 / Virus Database: 269.21.3/1306 - Release Date:
        01/03/2008
        > 17:41
        >
      • Udo Deutscher
        Nils, I can very well understand Tracey. These bandwidths are needed in NDB (beacon) DXing to separate an ident modulation from a nearby carrier. In Europe,
        Message 3 of 23 , Mar 2, 2008
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          Nils, I can very well understand Tracey.

          These bandwidths are needed in NDB (beacon) DXing to separate an ident
          modulation from a nearby carrier.

          In Europe, where many countries use 1020 Hz A2a modulation, the beacon
          ident comes e.g. for a beacon on 352 kHz: on 350.98 and 353.02 kHz. If
          I have strong carriers on 351 and on 353 kHz, the only way to identify
          the beacon of 352 consists in having a very narrow filter.

          I also would like to get such filters like 20Hz bandwith in my Perseus.

          73
          Udo, DL3GN
        • schiffhauer.nils
          Hi, Udo & Tracey - I do also receive NDBs, plus receiving faint radio stations, 30 or more dB too weak to be heard. For these purposes I do use audio
          Message 4 of 23 , Mar 2, 2008
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            Hi, Udo & Tracey - I do also receive NDBs, plus receiving faint radio
            stations, 30 or more dB too weak to be heard. For these purposes I do
            use audio analyzers, providing bandwidths well below 0.1 Hz, and
            analyzing the results graphically. Due to the modulation of the NDBs,
            there should be a limit of around 1 to 0,1 Hz to recover the callsign.
            Thus, this will give an enhancement of 10 to 20 dB over a 10 Hz filter
            (plus some additional dBs by the specific pattern recognition of the
            system of eyes & brain). The very wide dynamic range, also for stations
            within tight vicinity, of the receiver will deliver perfect results and
            undigging even some "new ones".
            There are really no problems to seperate so-called "co-channel"
            stations on medium wave, only a fraction of an hertz apart. I made this
            some ten years ago with conventional receivers (like EK071, AGC OFF, IF-
            bandwidth around 100 Hz), and a Motorola DSP kit. Nowadays, we can do
            this all in software only. And with Perseus we do have a receiver with
            a pure local oscillator, plus a wide dynamic range - a must to resolve
            these situations.
            Thus, I may have overlooked something, because I never missed IF
            filters under 100 Hz - at least for my purposes. It is even possible to
            distinguish between x- and o-rays of one signal, if their Doppler
            difference measures only some millihertz.
            For all these tasks, I do prefer SBSpectrum, but e.g. SpectrumLab of
            course is a more versatile software, whereas NDBfinder
            (http://www.coaa.co.uk/ndbfinder.htm) is more specialzed to NDBs.
            Thus, from my point of view there is no need for smaller filter
            bandwidth (especially in an SDR without classical "roofing filters")
            than e.g. 100 Hz or so for even the most demanding purposes.
            But I have the feeling, I didn't get the clue. So any hint is welcomed!
            Have fun; 73: Nils, DK8OK



            --- In perseus_SDR@yahoogroups.com, "Udo Deutscher" <udo.deutscher@...>
            wrote:
            >
            > Nils, I can very well understand Tracey.
            >
            > These bandwidths are needed in NDB (beacon) DXing to separate an ident
            > modulation from a nearby carrier.
            >
            > In Europe, where many countries use 1020 Hz A2a modulation, the beacon
            > ident comes e.g. for a beacon on 352 kHz: on 350.98 and 353.02 kHz. If
            > I have strong carriers on 351 and on 353 kHz, the only way to identify
            > the beacon of 352 consists in having a very narrow filter.
            >
            > I also would like to get such filters like 20Hz bandwith in my
            Perseus.
            >
            > 73
            > Udo, DL3GN
            >
          • Leif Asbrink
            Hi Udo, ... Hmmm, another alternative would be very narrow notch filters:-) ... Maybe you could make a recording of a case that you find very difficult with
            Message 5 of 23 , Mar 2, 2008
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              Hi Udo,

              > Nils, I can very well understand Tracey.
              >
              > These bandwidths are needed in NDB (beacon) DXing to separate an ident
              > modulation from a nearby carrier.
              >
              > In Europe, where many countries use 1020 Hz A2a modulation, the beacon
              > ident comes e.g. for a beacon on 352 kHz: on 350.98 and 353.02 kHz. If
              > I have strong carriers on 351 and on 353 kHz, the only way to identify
              > the beacon of 352 consists in having a very narrow filter.
              Hmmm, another alternative would be very narrow notch filters:-)

              > I also would like to get such filters like 20Hz bandwith in my Perseus.
              Maybe you could make a recording of a case that you find very difficult
              with the best tools currently at your disposal. I would be interested
              to try with Linrad to see how well can receive these signals.

              73

              Leif / SM5BSZ
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