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LHS Episode #118: Making Flippy Floppy, Sol Style

November 27th, 2013 |

Hello, friends! Episode #118 of Linux in the Ham Shack is ready for your immediate consumption. Lots of ham radio and Linux related news in this episode, including discussion of Ham Radio Now, the sun's magnetosphere, digital contacts on 28MHz, Linux Mint, Linux news aggregation sites and more. Sit back in your easy chair, put on your headphones, and enjoy a sweet slice of podcast nirvana. Until next time...

73 de The LHS Guys

Solar Plasma Filament Eruption – The Sun – November 6,7 2013

November 7th, 2013 |

Author: Tomas NW7US

The Sun currently is active, with powerful, complex magnetic structures that have formed a healthy number of sunspots. We are seeing a fair number of x-ray flares, which push the 10.7-cm flux higher than we’ve seen in a while.

Sunspots and flares means better propagation in general, especially on the higher frequencies of the shortwave spectrum. While a flare can cause a short period of “blackout” conditions (especially on the lower frequencies) on the sunlit side of the Earth, such activity is part of the positive activity that ionizes the F-region, providing for DX.

Here’s a movie of one such flare and the release of solar plasma, a release known as a coronal mass ejection (CME): At about midnight, UTC, on 6 November 2013, a moderately-strong M-class flare erupted, with a “beautiful” CME: http://g.nw7us.us/18a0QvI

(Source: SOHO/SDO/NASA)

We will see continued flare activity over the weekend, so expect great conditions on the HF bands, with momentary blackouts. Keep up to the minute on space weather at http://SunSpotWatch.com

73 – de NW7US
Propagation Columnist, CQ Communications Magazine, Popular Communications Magazine
http://NW7US.us

At 522,000,000 miles per watt, Voyager 1 might be the ultimate in QRP.

October 2nd, 2013 |

Author: Owen KF5CZO

At 522,000,000 miles per watt, Voyager could be the ultimate in QRP … if you have the right antenna.

For most HAMs the experience of seeing sub-one watt WSPR signals decoded from across the globe is enough of a thrill. However, the fine folks at the National Radio Astronomy Observatory have taken this a little further and used the Very Long Baseline Array radio telescope to precisely pinpoint the position of the Voyager 1 space probe.

While the layperson might see detecting the glimmer of 22 watts across the vastness of space miraculous, the amateur radio community can see this feat as the natural evolution and refinement of the technology and medium we know and love.

From nrao.edu:

Earlier this year, the National Science Foundation’s Very Long Baseline Array telescope turned its gaze to NASA’s famed Voyager 1 and captured an image of this iconic spacecraft’s faint radio signal. The Green Bank Telescope also detected Voyager’s signal, picking it out from the background radio noise in less than one second.

Astronomers using the National Science Foundation’s (NSF) Very Long Baseline Array (VLBA) and Green Bank Telescope (GBT) spotted the faint radio glow from NASA’s famed Voyager 1 spacecraft — the most distant man-made object.

According to NASA’s Jet Propulsion Laboratory (JPL), the VLBA imaged the signal from Voyager 1’s main transmitter after the spacecraft had already passed beyond the edge of the heliosphere, the bubble of charged particles from the Sun that surrounds our Solar System.

Using NASA’s Deep Space Network, JPL continually tracks Voyager and calculates its position on the sky, which is known as the ephemeris. Since the VLBA has the highest resolution, or ability to see fine detail, of any full-time astronomical instrument, NRAO astronomers believed they could locate Voyager’s ephemeris position with unprecedented precision. This is unrelated to Voyager’s distance from the Sun or position relative to the heliosphere.

The initial observations, which were made on February 21, placed Voyager very near, but not precisely at its predicted location. The difference was a few tenths of an arcsecond. An arcsecond is the apparent size of a penny as seen from 2.5 miles (4 kilometers) away. The second observations on June 1 produced similar results.

“It is possible that these observations are at the milliarcsecond [one-thousandth of an arcsecond] level, or better,” said NRAO scientist Walter Brisken, who led the observations with the VLBA. At 11.5 billion miles — Voyager’s approximate distance at the time of the initial observations — one milliarcsecond would be roughly 50 miles across.

Voyager’s main transmitter shines at a feeble 22 watts, which is comparable to a car-mounted police radio or — in visible light — a refrigerator light bulb. Though incredibly weak by the standards of modern wireless communications, Voyager’s signal is astoundingly bright when compared to most natural objects studied by radio telescopes.

“The ability to pinpoint the location of Voyager and other spacecraft is critical as we explore the inner Solar System and beyond,” said Brisken. “The NRAO’s VLBA has the capability to do this vital task with unprecedented precision.”

Voyager 1, which was launched in 1977, is now headed away from the Sun at a speed of about 38,000 miles per hour.

In a remarkably sensitive complementary observation, the NRAO’s Green Bank Telescope (GBT), which is the world’s largest fully steerable radio telescope, easily detected Voyager’s signal, picking it out from the background radio noise in less than one second.

“Voyager is the first man-made object to penetrate the interstellar medium, and we really want to be able to receive the data from this new frontier,” said NRAO scientist Toney Minter, who oversaw the Green Bank observations. “This information will provide many clues about how the interstellar medium behaves and how the Sun interacts with it.”

“NRAO’s instruments have the capability to provide the most accurate position information of distant spacecraft like Voyager,” said NRAO Director Tony Beasley. “The remarkable sensitivity of GBT and VLBA’s sharp vision are essential for discovery but also have unique capabilities that have enabled us to make this contact with one of humanity’s most ambitious missions of exploration.”

The VLBA is a system of radio antennas located across the United States from Hawaii to St. Croix. The antennas work together as a single telescope nearly 5,000 miles across, giving the VLBA its ability to see fine details. Only seven of the VLBA’s full complement of 10 antennas were used to make these observations.

The 100-meter GBT is located in the National Radio Quiet Zone and the West Virginia Radio Astronomy Zone, which protect the incredibly sensitive telescope from unwanted radio interference. The GBT observations were made by NRAO scientists Toney Minter and Frank Ghigo, and Green Bank Director Karen O’Neil.

Geomagnetic data reveal unusual nature of recent solar minimum

March 19th, 2012 |

Author: Owen KF5CZO

An interesting article appeared on physorg.com yesterday regarding changes in the Earth’s magnetic field and its relation to solar activity. Although short on detail it hints at significant changes going on within our sun.

Since the mid-1800s, scientists have been systematically measuring changes in the Earth’s magnetic field and the occurrence of geomagnetic activity. Such long- term investigation has uncovered a number of cyclical changes, including a signal associated with 27-day solar rotation.

This is most clearly seen during the declining phase and minimum of each 11-year solar cycle, when the Sun’s magnetic dipole is sometimes tilted with respect to the Sun’s rotational axis. With the Sun’s rotation and the emission of solar wind along field lines from either end of the solar magnetic dipole, an outward propagating spiral-like pattern is formed in the solar wind and the interplanetary magnetic field that can drive 27-day, and occasionally 13.5-day, recurrent geomagnetic activity.

Recurrent geomagnetic activity can also be driven by isolated and semipersistent coronal holes, from which concentrated streams of solar wind can be emitted.

During the most recent solar minimum, which took place from 2006 to 2010, however, several researcher groups noticed 6.7-day and 9-day recurrent changes in geomagnetic activity, and similar patterns in the interplanetary magnetic field, and the solar wind. Using modern data covering the previous two solar minima, these higher-frequency occurrences were judged to be unusual.

Love et al. analyzed historical geomagnetic activity records from 1868 to 2011 and find that the 6.7-day and 9-day recurrent changes were actually unique in the past 140 years.They suggest that the higher-frequency changes in geomagnetic activity are due to an unusual transient asymmetry in the solar dynamo, the turbulent, rotating plasma deep within the sun which generates the magnetic field.

More information: Geomagnetic detection of the sectorial solar magnetic field and the historical peculiarity of minimum 23-24 Geophysical Research Letters, doi:10.1029/2011GL050702 , 2012

Provided by American Geophysical Union

“Geomagnetic data reveal unusual nature of recent solar minimum.”

March 19th, 2012. http://www.physorg.com/news/2012-03-geomagnetic-reveal-unusual-nature-solar.html

Solar news

March 7th, 2012 |

Author: Stephen VK2RH

Under the title “Earth braces for biggest space storm in five years” ABC Australia’s online news reports on the last 24 hours of solar activity.

A NOAA space scientist is quoted “Space weather has gotten very interesting over the past 24 hours”.

Further detail as usual from http://www.spaceweather.com and http://www.swpc.noaa.gov/today.html.

UPDATE: 24 hours later – “Space storm fizzle“!

AmateurRadio.com