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Realistic noise levels

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  • Mark D Mobile
    Hello to all. I’ve been using my Perseus with various verticals; 30-foot and 50-foot. I ve been careful to find quiet locations. Reviewing the recordings,
    Message 1 of 15 , Jul 1, 2012
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      Hello to all. I’ve been using my Perseus with various verticals; 30-foot
      and 50-foot. I've been careful to find quiet locations.

      Reviewing the recordings, I’m seeing MW noise floors (around 1750 kHz) that
      average about –112 dbm at 6.04 kHz bandwidth.

      C/N for even the weak stations is 20db or better.

      I’m wondering if this is considered good noise performance? What's your
      experience?

      Mark Durenberger
      On the Road
    • Werner Karn
      Hello Mark, the noise floor of my Perseus at 6 kHz bandwidth is around -118dBm. If your antenna adds another 6 dB than you are making full use of your receiver
      Message 2 of 15 , Jul 1, 2012
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        Hello Mark,
         
        the noise floor of my Perseus at 6 kHz bandwidth is around -118dBm. If your antenna adds another 6 dB than you are making full use of your receiver sensitivity and the signal to noise ratio will be fully dependant on your antenna and the local noise situation. Most local noise is not broadband, so you can see it in the spectrum and measure it and look for a quite location. The rest, to my experience, is just antenna length or antenna area, height and diagram. For MW beverages or big loops should give best results.
         
        73,
         
        Werner 
        2012/7/1 Mark D Mobile <Mark4@...>
         

        Hello to all. I’ve been using my Perseus with various verticals; 30-foot
        and 50-foot. I've been careful to find quiet locations.

        Reviewing the recordings, I’m seeing MW noise floors (around 1750 kHz) that
        average about –112 dbm at 6.04 kHz bandwidth.

        C/N for even the weak stations is 20db or better.

        I’m wondering if this is considered good noise performance? What's your
        experience?

        Mark Durenberger
        On the Road


      • Wolfgang Bueschel
        Seen very quiet Perseus levels around -138dbm at Victor 4S7VK in Sri Lanka and also seen here on Ulm university unit too, -135dbm at Jerry s place in Iowa-USA.
        Message 3 of 15 , Jul 1, 2012
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          Seen very quiet Perseus levels around

          -138dbm at Victor 4S7VK in Sri Lanka
          and also seen here on Ulm university unit too,
          -135dbm at Jerry's place in Iowa-USA.

          But in my Stuttgart suburb suffer by -78dbm rather noisy. 73 wb df5sx

          ----- Original Message -----
          From: "Werner Karn" <werner.karn@...>
          Sent: Sunday, July 01, 2012 4:43 PM
          Subject: Re: [perseus_SDR] Realistic noise levels

          Hello Mark,
          the noise floor of my Perseus at 6 kHz bandwidth is around -118dBm. If your
          antenna adds another 6 dB than you are making full use of your receiver
          sensitivity and the signal to noise ratio will be fully dependant on your
          antenna and the local noise situation. Most local noise is not broadband,
          so you can see it in the spectrum and measure it and look for a quite
          location. The rest, to my experience, is just antenna length or antenna
          area, height and diagram. For MW beverages or big loops should give best
          results.
          73, Werner

          2012/7/1 Mark D Mobile <Mark4@...>
          > Hello to all. I’ve been using my Perseus with various verticals; 30-foot
          > and 50-foot. I've been careful to find quiet locations.
          >
          > Reviewing the recordings, I’m seeing MW noise floors (around 1750 kHz)
          > that average about –112 dbm at 6.04 kHz bandwidth.
          >
          > C/N for even the weak stations is 20db or better.
          >
          > I’m wondering if this is considered good noise performance? What's your
          > experience?
          >
          > Mark Durenberger
          > On the Road
        • Werner Karn
          Wolfgang, What bandwidths are you referring to ? Mark gave 6 kHz for comparison. 73, Werner ... Wolfgang, What bandwidths are you referring to ? Mark gave 6
          Message 4 of 15 , Jul 1, 2012
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            Wolfgang,

            What bandwidths are you referring to ? Mark gave 6 kHz for comparison.

            73,

            Werner

            Am Sonntag, 1. Juli 2012 schrieb Wolfgang Bueschel :
            Seen very quiet Perseus levels around

            -138dbm at Victor 4S7VK in Sri Lanka
            and also seen here on Ulm university unit too,
            -135dbm at Jerry's place in Iowa-USA.

            But in my Stuttgart suburb suffer by -78dbm rather noisy. 73 wb df5sx

            ----- Original Message -----
            From: "Werner Karn" <werner.karn@...>
            Sent: Sunday, July 01, 2012 4:43 PM
            Subject: Re: [perseus_SDR] Realistic noise levels

            Hello Mark,
            the noise floor of my Perseus at 6 kHz bandwidth is around -118dBm. If your
            antenna adds another 6 dB than you are making full use of your receiver
            sensitivity and the signal to noise ratio will be fully dependant on your
            antenna and the local noise situation. Most local noise is not broadband,
            so you can see it in the spectrum and measure it and look for a quite
            location. The rest, to my experience, is just antenna length or antenna
            area, height and diagram. For MW beverages or big loops should give best
            results.
            73, Werner

            2012/7/1 Mark D Mobile <Mark4@...>
            > Hello to all. I’ve been using my Perseus with various verticals; 30-foot
            > and 50-foot. I've been careful to find quiet locations.
            >
            > Reviewing the recordings, I’m seeing MW noise floors (around 1750 kHz)
            > that average about –112 dbm at 6.04 kHz bandwidth.
            >
            > C/N for even the weak stations is 20db or better.
            >
            > I’m wondering if this is considered good noise performance? What's your
            > experience?
            >
            > Mark Durenberger
            > On the Road



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          • Keith
            Using the 55x110 ft superloop here and my average is about -117 dbm on 1750khz using the 6 khz bw. On 500 khz it s about -114 dbm. Keith McGinnis Hingham MA
            Message 5 of 15 , Jul 1, 2012
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              Using the 55x110 ft superloop here and my average is about -117 dbm on
              1750khz using the 6 khz bw. On 500 khz it's about -114 dbm.

              Keith McGinnis
              Hingham MA

              On 7/1/2012 8:05 AM, Mark D Mobile wrote:
              > Hello to all. I’ve been using my Perseus with various verticals; 30-foot
              > and 50-foot. I've been careful to find quiet locations.
              >
              > Reviewing the recordings, I’m seeing MW noise floors (around 1750 kHz) that
              > average about –112 dbm at 6.04 kHz bandwidth.
              >
              > C/N for even the weak stations is 20db or better.
              >
              > I’m wondering if this is considered good noise performance? What's your
              > experience?
              >
              > Mark Durenberger
              > On the Road
              >
              >
              >
            • Roelof Bakker
              Hello Mark, The only thing that counts is the signal to noise ratio. Look e.g. at the same antenna used at home or at a field location. It had a 9 dB higher
              Message 6 of 15 , Jul 1, 2012
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                Hello Mark,

                The only thing that counts is the signal to noise ratio.
                Look e.g. at the same antenna used at home or at a field location.
                It had a 9 dB higher noise floor in the field, however still weak signal
                work was better due to a better signal to noise ratio.

                Working for the lowest possible noise floor with the same antenna is the
                way to go.
                This is a tricky game and I use stations within close range for testing.
                The noise will often vary over the band and this should be taken into
                account as well.

                However, the PERSEUS is a very nice tool to evaluate your noise situation.
                For a wide band view, HF-Span is very nice indeed.
                And very educational!

                73,
                Roelof Bakker, pa0rdt
              • Mark D Mobile
                Thank you Werner for your input. I guess I’m not too far off the reservation, because the vertical also does a dandy job with signals. Mark Durenberger On
                Message 7 of 15 , Jul 1, 2012
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                  Thank you Werner for your input.  I guess I’m not too far off the reservation, because the vertical also does a dandy job with signals.
                   
                  Mark Durenberger
                  On the Road
                   
                  Sent: Sunday, July 01, 2012 9:43 AM
                  Subject: Re: [perseus_SDR] Realistic noise levels
                   
                   

                  Hello Mark,
                   
                  the noise floor of my Perseus at 6 kHz bandwidth is around -118dBm. If your antenna adds another 6 dB than you are making full use of your receiver sensitivity and the signal to noise ratio will be fully dependant on your antenna and the local noise situation. Most local noise is not broadband, so you can see it in the spectrum and measure it and look for a quite location. The rest, to my experience, is just antenna length or antenna area, height and diagram. For MW beverages or big loops should give best results.
                   
                  73,
                   
                  Werner
                  2012/7/1 Mark D Mobile <Mark4@...>
                   

                  Hello to all. I’ve been using my Perseus with various verticals; 30-foot
                  and 50-foot. I've been careful to find quiet locations.

                  Reviewing the recordings, I’m seeing MW noise floors (around 1750 kHz) that
                  average about –112 dbm at 6.04 kHz bandwidth.

                  C/N for even the weak stations is 20db or better.

                  I’m wondering if this is considered good noise performance? What's your
                  experience?

                  Mark Durenberger
                  On the Road


                • Mark D Mobile
                  Roelof, thank you for that perspective. I always try to log “C/N” (Carrier-to-Noise)...can be same thing as S/N I suppose. C/N must be a hangover from my
                  Message 8 of 15 , Jul 1, 2012
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                    Roelof, thank you for that perspective.  I always try to log “C/N” (Carrier-to-Noise)...can be same thing as S/N I suppose.  C/N must be a hangover from my satellite days.
                     
                    Mark Durenberger
                    On the Road
                     
                    Sent: Sunday, July 01, 2012 10:59 AM
                    Subject: Re: [perseus_SDR] Realistic noise levels
                     
                     

                    Hello Mark,

                    The only thing that counts is the signal to noise ratio.
                    Look e.g. at the same antenna used at home or at a field location.
                    It had a 9 dB higher noise floor in the field, however still weak signal
                    work was better due to a better signal to noise ratio.

                    Working for the lowest possible noise floor with the same antenna is the
                    way to go.
                    This is a tricky game and I use stations within close range for testing.
                    The noise will often vary over the band and this should be taken into
                    account as well.

                    However, the PERSEUS is a very nice tool to evaluate your noise situation.
                    For a wide band view, HF-Span is very nice indeed.
                    And very educational!

                    73,
                    Roelof Bakker, pa0rdt

                  • Mark D Mobile
                    Thanks to all who added information to this topic. I learn there’s always room for improvement; even 1 db at a time adds up! When I return to land I’ll
                    Message 9 of 15 , Jul 2, 2012
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                      Thanks to all who added information to this topic.  I learn there’s always room for improvement; even 1 db at a time adds up!
                       
                      When I return to land I’ll post a couple of fairly-quiet MW recordings to Guy Atkins’ site.
                       
                       
                      Mark Durenberger
                      On the Road
                       
                      From: Keith
                      Sent: Sunday, July 01, 2012 10:49 AM
                      Subject: Re: [perseus_SDR] Realistic noise levels
                       
                       

                      Using the 55x110 ft superloop here and my average is about -117 dbm on
                      1750khz using the 6 khz bw. On 500 khz it's about -114 dbm.

                      Keith McGinnis
                      Hingham MA

                      On 7/1/2012 8:05 AM, Mark D Mobile wrote:
                      > Hello to all. I’ve been using my Perseus with various verticals; 30-foot
                      > and 50-foot. I've been careful to find quiet locations.
                      >
                      > Reviewing the recordings, I’m seeing MW noise floors (around 1750 kHz) that
                      > average about –112 dbm at 6.04 kHz bandwidth.
                      >
                      > C/N for even the weak stations is 20db or better.
                      >
                      > I’m wondering if this is considered good noise performance? What's your
                      > experience?
                      >
                      > Mark Durenberger
                      > On the Road
                      >
                      >
                      >

                    • aperseus2
                      Thank you very much Dave and Guy for these files. It makes a lot of fun. 73 Hans, DL4YBP
                      Message 10 of 15 , Jul 5, 2012
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                        Thank you very much Dave and Guy for these files. It makes a lot of fun.

                        73
                        Hans, DL4YBP


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