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Re: Question About Band Scope Performance

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  • 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 1 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 2 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 3 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 4 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 5 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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