AmateurRadio.com

Shortwave radio history – communications in and out of New Zealand in 1939. This history is rich with adventure and successes that are profound. Our modern communications all stems from this historic work…

This is a short film about the romance of the radiotelegraph service that utilized the high frequency spectrum known as “shortwave” (from 3 MHz up to 30 MHz) as well as the longwave and medium frequency spectrum (below 3 MHz).  This is a short film about communication to and from New Zealand on these shortwaves, using Morse code (eventually, using CW modulation). This film is a 1939 Government film scanned to 2K from a 16mm combined B/W reduction print.

http://g.nw7us.us/1cIn92f 

Every approximately eleven years, the Sun produces a “cycle” of sunspot activity. At the very lowest point in this cycle, there are few, if any, sunspots observed. Such a lack of sunspots can last for weeks. During the peak of the sunspot cycle, there can be a multitude of sunspots, ranging in size. This cycle is known as the sunspot cycle. It is caused, in part, by the magnetic activity within the Sun. Every eleven years, the Sun’s magnetic polarity flips–the north becomes south, the south becomes north. This is normal. Every twenty two years, then, the Sun goes through one full magnetic flip cycle. The flipping seems to coincide with the timing of solar cycle maxima. When it flips, we know about where we are in the eleven-year cycle. The magnetic polarity of the Sun appears to be in the process of reversing, over the next few months. If so, then we’ve pretty much reached the sunspot cycle maxima for Cycle 24. Observers note that this cycle is quite a bit less active than the last few eleven-year cycles.

A video that talks about this reversal is here:

The flipping of the Sun’s magnetic poles: Sunspot Cycle 24

More information on the Sun and the cycle, radio propagation, and related topics:

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A magnificent eruption ejected a massive cloud of solar plasma out away from the Sun, into interplanetary space on September 29th (2013/09/29).  A long filament of plasma hovered above the photosphere, captured by the magnetism in the Sun’s northern hemisphere.  Then, it erupted in spectacular energy as seen by the Solar Dynamics Observatory, and by Stereo and SOHO spacecraft. This plasma eruption produced a stunningly beautiful coronal mass ejection (CME).

Coronal mass ejections are often associated with solar activity such as solar flares, but a causal relationship has not been established. A coronal mass ejection is also produced when a plasma filament (or prominence) breaks away from the magnetic clutch of the Sun, escaping the gravitational pull. While many plasma ejections originate from active regions on the Sun’s surface, such as groupings of sunspots associated with frequent flares, any plasma formation could break away. Near solar maxima, the Sun produces about three CMEs every day, whereas near solar minima, there is about one CME every five days or even less frequently.

When a CME passes Earth (not all CMEs are directed toward the Earth), it could cause geomagnetic disturbances, triggering aurora and causing disruption of shortwave radio communications.

Although this CME was not aimed at Earth, it passed by the Earth with a glancing blow from the plasma cloud on October 2-3 2013. This caused a geomagnetic storm (minor level), which lowered the Maximum Usable Frequency (MUF) over many ionospheric radio-wave propagation paths on shortwave radio.  This lowing of the MUF is often regarded as a
degradation of shortwave radio conditions.  Some aurora is also produced, though this event did not cause much significant aurora.

Here’s a video showing the magnificent plasma eruption and CME:

Credit: SOHO/Stereo/SDO/NASA

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Aurora Watch: http://Aurora.SunSpotWatch.com