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Re: [perseus_SDR] Low received signal level.

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  • Roelof Bakker
    Hello José, The sensitivity of the PERSEUS drops at the higher bands, however it is still OK for use on ten meters with a decent antenna. A way to check is to
    Message 1 of 2 , Jul 12, 2013
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      Hello José,

      The sensitivity of the PERSEUS drops at the higher bands, however it is
      still OK for use on ten meters with a decent antenna.

      A way to check is to run HF Span set to 0-40 MHz.
      This gives an excellent view of HF conditions, noise floor and local noise.
      Could you forward a screen shot direct to me?

      I might be able to provide some advise.

      73,
      Roelof Bakker, pa0rdt
    • José Angel Amador
      I have been using a Perseus both with its own software and HDSDR 2.62. All fine below 10 MHz, where there is plenty of noise as well. But above 14 MHz there is
      Message 2 of 2 , Jul 12, 2013
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        I have been using a Perseus both with its own software and HDSDR 2.62.
        All fine below 10 MHz, where there is plenty of noise as well. But above
        14 MHz there is almost no background noise seen on the spectrum or the
        waterfalls, weak signals can be received aurally, but almost on the
        blind. There is no problem with filters or attenuators, as the radio
        works well on the lower frequencies, to the point of saturating on
        medium wave and below. Not a problem at all, the attenuator takes care
        of that properly. I have switched filters and attenuators in and out,
        and there is nothing broken, only that I would like to be able to see
        the noise floor as grass as well as on lower frequencies.

        Is there any adjustment, I suppose that in software, to raise the output
        level?

        I am conscious that the situation I have attempted to describe may obey
        to some proper level calibration issue, but I am lost about getting
        working solutions for my particular case. I live in the outskirts of
        Havana, but I have a 13.8 kV power line that passes near my home, and
        above the tips of the trees I can see EHV power lines some 300 meters
        away. And it gives a background noise level of about S-6 on 7 MHz. I am
        aware of that because when we were without power for two days in
        November 2001 after hurricane Michelle passed just nearby, all such
        noise disappeared. Signals popped out of nowhere on my FT-757 running
        on a 12V truck battery.

        Using heterodyne receivers with quadrature sampling detectors (like the
        Genesis G40 I have also been using) it is just a matter of increasing
        the line input audio gain to get to see the grass, and signals above it.
        But I don't know what to do in the case of the Perseus, feeding the PC
        with a USB data stream instead of audio.

        My soundcard with the G40 is a 24 bit Audigy 2.

        Weak signals audio with HDSDR becomes choppy, as the squelch attempts to
        act even when I always believed it was wide open, with the squelch
        threshold red line at the lower end of the S meter travel,

        Looking forward for suggestions, ideas, and hints about what to read,

        José, CO2JA
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