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187Re: [dxatlas] 90-day SSN data for HamCAP

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  • Alex, VE3NEA
    Apr 9, 2005
      > Yet the average montthly sunspots for the past 3 months are:
      > 2005 01 31.3
      > 2005 02 29.1
      > 2005 03 24.8
      > Average = 28.4, which is very close to the built-in 30 and current
      > NOAA predicted 28.5.
      > ftp://ftp.ngdc.noaa.gov/STP/SOLAR_DATA/SUNSPOT_NUMBERS/MONTHLY.PLT
      > How can IonoProbe's computed 90-day SSN possibly be 47? This is
      > different by nearly a factor of two!

      I am not sure how monthly values presented on that page are calculated.
      IonoProbe just averages the last 90 daily values from
      http://www.sec.noaa.gov/ftpdir/latest/DSD.txt and
      http://www.sec.noaa.gov/ftpdir/indices/old_indices/




      > Could IonoProbe's calculation be off by one year? I notice 47 is very
      > close to the SSN numbers for this time last year:
      > 2004 52.0 49.3 47.1 45.6 43.9 41.7 40.2 39.2 37.5
      > ftp://ftp.ngdc.noaa.gov/STP/SOLAR_DATA/SUNSPOT_NUMBERS/SMOOTHED
      > And the average of 49.3, 47.1, and 45.6 is 47.3. Maybe the logic of
      > the calculation has an error somewhere in its data collection.

      IonoProbe does not have access to the data from the last year.


      > Definitely so. The current 90 day average (1 Jan 05 - 31 Mar 05) is
      > 28.4 using this data:
      > ftp://ftp.ngdc.noaa.gov/STP/SOLAR_DATA/SUNSPOT_NUMBERS/RIDAILY.PLT

      These are the RI indices, not daily SSN values.



      > Anyhow, now I
      > know what to use and will probably just go with the NOAA forecast
      > which seems to be fairly accurate at this stage of the cycle.

      You may want to enter the latest NOAA forecasts in the SSN.dat file using
      Notepad, then HamCap will use these data automatically.


      73 Alex VE3NEA
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