[Hammarlund] Hammarlund Restoration & Noise Level
Frank Barnes
fbw4npn at gmail.com
Thu Jun 6 17:31:24 EDT 2019
The mid-to-late 1950's was when I got into ham radio. We could work into
nearly any location with low power. Sure wish those old sunspots would
come back.
On Thu, Jun 6, 2019 at 4:22 PM D.J.J. Ring, Jr. <djringjr at gmail.com> wrote:
> The *Maunder Minimum*, also known as the "prolonged sunspot minimum", is
> the name used for the period around 1645 to 1715 during which sunspots
> <https://en.m.wikipedia.org/wiki/Sunspot> became exceedingly rare, as was
> then noted by solar observers.
>
> The term was introduced after John A. Eddy
> <https://en.m.wikipedia.org/wiki/John_A._Eddy>[1]
> <https://en.m.wikipedia.org/wiki/Maunder_Minimum#cite_note-1> published a
> landmark 1976 paper in *Science*
> <https://en.m.wikipedia.org/wiki/Science_%28journal%29>.[2]
> <https://en.m.wikipedia.org/wiki/Maunder_Minimum#cite_note-MM_PAPER-2> Astronomers
> before Eddy had also named the period after the solar astronomers Annie
> Russell Maunder <https://en.m.wikipedia.org/wiki/Annie_Russell_Maunder> (1868–1947)
> and her husband, Edward Walter Maunder
> <https://en.m.wikipedia.org/wiki/Edward_Walter_Maunder> (1851–1928), who
> studied how sunspot latitudes changed with time.[3]
> <https://en.m.wikipedia.org/wiki/Maunder_Minimum#cite_note-3> The period
> which the spouses examined included the second half of the 17th century.
>
> Two papers were published in Edward Maunder's name in 1890[4]
> <https://en.m.wikipedia.org/wiki/Maunder_Minimum#cite_note-4> and 1894,[5]
> <https://en.m.wikipedia.org/wiki/Maunder_Minimum#cite_note-5> and he
> cited earlier papers written by Gustav Spörer
> <https://en.m.wikipedia.org/wiki/Gustav_Sp%C3%B6rer>.[6]
> <https://en.m.wikipedia.org/wiki/Maunder_Minimum#cite_note-6> Because
> Annie Maunder had not received a university degree, restrictions at the
> time caused her contribution not to be publicly recognized.[7]
> <https://en.m.wikipedia.org/wiki/Maunder_Minimum#cite_note-bruck1994-7>
>
> Spörer noted that, during a 28-year period (1672–1699) within the Maunder
> Minimum, observations revealed fewer than 50 sunspots.
>
> This contrasts with the typical 40000 – 50000 sunspots seen in modern
> times (over similar 25 year sampling).[8]
> <https://en.m.wikipedia.org/wiki/Maunder_Minimum#cite_note-8>
> Like the Homeric Minimum <https://en.m.wikipedia.org/wiki/Homeric_Minimum>
> , Dalton Minimum <https://en.m.wikipedia.org/wiki/Dalton_Minimum> and the Spörer
> Minimum <https://en.m.wikipedia.org/wiki/Sp%C3%B6rer_Minimum>, the
> Maunder Minimum coincided with a period of lower-than-average
> <https://en.m.wikipedia.org/wiki/Little_Ice_Age> European temperatures.'
>
> '[image: Graph of average yearly sunspot numbers showing the 11-year
> solar cycle.]
> <https://www.britannica.com/science/Maunder-minimum/media/1/369980/143502>
>
>
> Maunder Minimum
>
> The *Maunder Minimum*, also known as the "prolonged sunspot minimum", is
> the name used for the period around 1645 to 1715 during which sunspots
> <https://en.m.wikipedia.org/wiki/Sunspot> became exceedingly rare, as was
> then noted by solar observers.
>
> The term was introduced after John A. Eddy
> <https://en.m.wikipedia.org/wiki/John_A._Eddy>[1]
> <https://en.m.wikipedia.org/wiki/Maunder_Minimum#cite_note-1> published a
> landmark 1976 paper in *Science*
> <https://en.m.wikipedia.org/wiki/Science_%28journal%29>.[2]
> <https://en.m.wikipedia.org/wiki/Maunder_Minimum#cite_note-MM_PAPER-2> Astronomers
> before Eddy had also named the period after the solar astronomers Annie
> Russell Maunder <https://en.m.wikipedia.org/wiki/Annie_Russell_Maunder> (1868–1947)
> and her husband, Edward Walter Maunder
> <https://en.m.wikipedia.org/wiki/Edward_Walter_Maunder> (1851–1928), who
> studied how sunspot latitudes changed with time.[3]
> <https://en.m.wikipedia.org/wiki/Maunder_Minimum#cite_note-3> The period
> which the spouses examined included the second half of the 17th century.
>
> Two papers were published in Edward Maunder's name in 1890[4]
> <https://en.m.wikipedia.org/wiki/Maunder_Minimum#cite_note-4> and 1894,[5]
> <https://en.m.wikipedia.org/wiki/Maunder_Minimum#cite_note-5> and he
> cited earlier papers written by Gustav Spörer
> <https://en.m.wikipedia.org/wiki/Gustav_Sp%C3%B6rer>.[6]
> <https://en.m.wikipedia.org/wiki/Maunder_Minimum#cite_note-6> Because
> Annie Maunder had not received a university degree, restrictions at the
> time caused her contribution not to be publicly recognized.[7]
> <https://en.m.wikipedia.org/wiki/Maunder_Minimum#cite_note-bruck1994-7>
>
> Spörer noted that, during a 28-year period (1672–1699) within the Maunder
> Minimum, observations revealed fewer than 50 sunspots.
>
> This contrasts with the typical 40000 – 50000 sunspots seen in modern
> times (over similar 25 year sampling).[8]
> <https://en.m.wikipedia.org/wiki/Maunder_Minimum#cite_note-8>
>
> Like the Homeric Minimum <https://en.m.wikipedia.org/wiki/Homeric_Minimum>
> , Dalton Minimum <https://en.m.wikipedia.org/wiki/Dalton_Minimum> and the Spörer
> Minimum <https://en.m.wikipedia.org/wiki/Sp%C3%B6rer_Minimum>, the
> Maunder Minimum coincided with a period of lower-than-average
> <https://en.m.wikipedia.org/wiki/Little_Ice_Age> European temperatures.
>
>
>
>
>
>
>
--
Frank Barnes
W4NPN
Chapel Hill, NC
Grid Square FM05
Cell 919.260.7955
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