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Question About Band Scope Performance

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  • Ryan
    First off, I can t wait for this scanner to be released. I m salivating. In the manual: Band Scope Mode searches a frequency range and displays the signal
    Message 1 of 6 , Dec 9, 2008
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      First off, I can't wait for this scanner to be released. I'm
      salivating.

      In the manual:

      "Band Scope Mode searches a frequency range and displays the signal
      level in real time."

      Does that mean the display updates in real time? What exactly is
      'real time' any way. I imgaine it has to tune each frequency in the
      range, right? So - the fastest it can go is 300 steps a second (with
      5kHz steps), or 100 steps a second when using any other step size.
      What I was unable to determine was how large a range you can set. Is
      there a limit?

      I am no expert, and maybe someone can check my math. In the visuals
      in the manual it shows a range between 850 and 852, with a 12.5khz
      step. That's 160 steps to search through, at 100 steps a second...
      meaning the display will update no faster than 1.6 seconds. Is this
      what "real time" means?

      Does this accuratly depict how this feature would work?
    • Ryan
      I accidentally hit return and this message got sent before I was able to modify it, so I am stuck responding to my own post. :-( ... Yes there is. It is in
      Message 2 of 6 , Dec 9, 2008
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        I accidentally hit 'return' and this message got sent before I was
        able to modify it, so I am stuck responding to my own post. :-(

        --- In BCD396XT@yahoogroups.com, "Ryan" <ryanisflyboy@...> wrote:
        > What I was unable to determine was how large a range you can set. Is
        > there a limit?

        Yes there is. It is in the manual. Here are the possible range spans:
        "You can select from 0.2 / 0.4 / 0.6 / 0.8 / 1 / 2 / 4 / 6 / 8 / 10 /
        20 / 40 / 60 / 80 / 100 / 120 / 140 / 160 /
        180 / 200 / 250 / 300 / 350 / 400 / 450 / 500 (MHz)."

        > I am no expert, and maybe someone can check my math. In the visuals
        > in the manual it shows a range between 850 and 852, with a 12.5khz
        > step. That's 160 steps to search through, at 100 steps a second...
        > meaning the display will update no faster than 1.6 seconds. Is this
        > what "real time" means?

        Based on information in the manual, this does look to be accurate
        (assuming my math is correct). This means the bigger the range, the
        longer it will take to refresh the scope. Band scope mode is
        essentially a visualization of a search operation. From the manual:
        "The search time changes depending on the search step size."

        I think my previous math was wayyyy off. What might be interesting is
        viewing, say, the entire FM broadcast range. How do you calculate
        the refresh time? If I have a 100Mhz range, 1,000 total frequencies
        at a step size of 100kHz, search rate of 100 per second = 10 seconds
        to refresh the band scope? I did fail math, you know. So don't trust
        me.

        > Does this accuratly depict how this feature would work?

        Still no clue. I'm still guessing. From the manual it looks like
        there is actually a visual indication where it is in the 'refresh'
        process (I think that is what the little "ray" icon shows). Also,
        with 32 bars to show the whole scope, I'm totally lost as to how easy
        it will be to tune to a 'spike' you are seeing in the scope. Nor do I
        understand how easy it will be to view a band, move center, zoom in,
        scan the band again, repeat. I look forward to seeing YouTube videos
        of this some day soon.

        To see what this looks like (statically), look here:
        http://info.uniden.com/mediawiki/index.php?title=Band_Scope_mode
      • Uniden UPMan
        You should also look in the software reference (page 189). I set my unit to a center frequency of 450 MHz, span of 6 MHz, and step of 12.5 kHz. Took about 6
        Message 3 of 6 , Dec 9, 2008
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          You should also look in the software reference (page 189).

          I set my unit to a center frequency of 450 MHz, span of 6 MHz, and step of 12.5 kHz. Took about 6 seconds to sweep.
          Changed to a 5 kHz step, it took about 13 seconds.
           UPMan




          ________________________________
          From: Ryan <ryanisflyboy@...>
          To: BCD396XT@yahoogroups.com
          Sent: Tuesday, December 9, 2008 4:44:08 PM
          Subject: [BCD396XT] Re: Question About Band Scope Performance


          I accidentally hit 'return' and this message got sent before I was
          able to modify it, so I am stuck responding to my own post. :-(

          --- In BCD396XT@yahoogroup s.com, "Ryan" <ryanisflyboy@ ....> wrote:
          > What I was unable to determine was how large a range you can set. Is
          > there a limit?

          Yes there is. It is in the manual. Here are the possible range spans:
          "You can select from 0.2 / 0.4 / 0.6 / 0.8 / 1 / 2 / 4 / 6 / 8 / 10 /
          20 / 40 / 60 / 80 / 100 / 120 / 140 / 160 /
          180 / 200 / 250 / 300 / 350 / 400 / 450 / 500 (MHz)."

          > I am no expert, and maybe someone can check my math. In the visuals
          > in the manual it shows a range between 850 and 852, with a 12.5khz
          > step. That's 160 steps to search through, at 100 steps a second...
          > meaning the display will update no faster than 1.6 seconds. Is this
          > what "real time" means?

          Based on information in the manual, this does look to be accurate
          (assuming my math is correct). This means the bigger the range, the
          longer it will take to refresh the scope. Band scope mode is
          essentially a visualization of a search operation. From the manual:
          "The search time changes depending on the search step size."

          I think my previous math was wayyyy off. What might be interesting is
          viewing, say, the entire FM broadcast range. How do you calculate
          the refresh time? If I have a 100Mhz range, 1,000 total frequencies
          at a step size of 100kHz, search rate of 100 per second = 10 seconds
          to refresh the band scope? I did fail math, you know. So don't trust
          me.

          > Does this accuratly depict how this feature would work?

          Still no clue. I'm still guessing. From the manual it looks like
          there is actually a visual indication where it is in the 'refresh'
          process (I think that is what the little "ray" icon shows). Also,
          with 32 bars to show the whole scope, I'm totally lost as to how easy
          it will be to tune to a 'spike' you are seeing in the scope. Nor do I
          understand how easy it will be to view a band, move center, zoom in,
          scan the band again, repeat. I look forward to seeing YouTube videos
          of this some day soon.

          To see what this looks like (statically) , look here:
          http://info. uniden.com/ mediawiki/ index.php? title=Band_ Scope_mode






          [Non-text portions of this message have been removed]
        • Uniden UPMan
          And just did it again using your example of the FM broadcast range: CF: 98 MHz Span: 20 MHz Step: 100 kHz Sweep time = just under 9 seconds per sweep (10
          Message 4 of 6 , Dec 9, 2008
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            And just did it again using your example of the FM broadcast range:

            CF: 98 MHz
            Span: 20 MHz
            Step: 100 kHz

            Sweep time = just under 9 seconds per sweep (10 sweeps took 88 seconds)
             UPMan




            ________________________________
            From: Uniden UPMan <uniden.upman@...>
            To: BCD396XT@yahoogroups.com
            Sent: Tuesday, December 9, 2008 5:07:48 PM
            Subject: Re: [BCD396XT] Re: Question About Band Scope Performance


            You should also look in the software reference (page 189).

            I set my unit to a center frequency of 450 MHz, span of 6 MHz, and step of 12.5 kHz. Took about 6 seconds to sweep.
            Changed to a 5 kHz step, it took about 13 seconds.
             UPMan

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            [Non-text portions of this message have been removed]
          • piccoracing
            Speaking of the band scope, what s the formula for converting RSSI(0-1023) to absolute dBm?
            Message 5 of 6 , Dec 10, 2008
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              Speaking of the band scope, what's the formula for converting
              RSSI(0-1023) to absolute dBm?
            • Ryan
              ... seconds) Perhaps this is much slower than I thought. Clearly I was way off regarding how to use a band scope. I apologize for not having a professional
              Message 6 of 6 , Dec 10, 2008
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                --- In BCD396XT@yahoogroups.com, Uniden UPMan <uniden.upman@...>
                wrote:
                > And just did it again using your example of the FM broadcast range:
                >
                > CF: 98 MHz
                > Span: 20 MHz
                > Step: 100 kHz
                >
                > Sweep time = just under 9 seconds per sweep (10 sweeps took 88
                seconds)

                Perhaps this is much slower than I thought. Clearly I was way off
                regarding how to use a band scope. I apologize for not having a
                professional background. I'm not even a competent amateur (put me in
                the beginner hobbyist category). Is the following right?

                20,000,000 Hz range.
                100,000 hz step
                -----------------
                200 possible steps in that range. right?

                Let's use the bigger benchmark you posted. In 10 sweeps it would look
                at 2,000 steps. 88 seconds to perform those 2,000 steps means it has
                a performance of about 22.72 steps a second. Is that right?

                Looking at the previous post:

                6,000,000 Hz range.
                12,500 Hz step = 480 steps / 6 seconds = 80 s/sec.
                5,000 Hz step = 1,200 steps / 13 seconds = 92 s/sec.

                Am I right? Maybe those of you good with math can create an easy to
                use forumla for determining band scope performance.

                The reason why I ask is really about the term 'real time.' Marketing
                people love this term, but the truth is there are so many ways to
                define it. What it means in this case (I would guess) is that the
                display updates in real-time, whenever the scanner actually gets
                around to checking that step (which may be quite a while depending on
                step size, range, etc).

                For those of you who are experts, can you share how this feature
                compares to other band scopes in the market?

                -Ryan
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