Meteor Scatter

Meteor scatter communications are also known as Meteor burst communication. It's a types of signal bounce possible only under specific circumstances. When a meteor enters the atmosphere of Earth an area of the E-layer is ionized.  This area is roughly cylindrical and like the tail of the meteor, it is long. When it first forms it is able to reflect and scatter radio signals.This ionization is brief, lasting from a few seconds to about a minute. The effect is observable from about 25 MHz up to about 10 GHz. Meteor skip allows a radio signal to bounce upwards of 900 miles.

 The earliest recorded observation of meteor scatter was by Hantaro Nagaoka of Nagasaki, Japan. He was then the chief physicist at the Institute of Physical and Chemical Research in Tokyo.  In 1929 he published a paper on his findings titled "The Possibility of radio Transmissions Being Disturbed by Meteoric Showers."  It sounds dry, but the 1929 Volume 5 issue of the Imperial Japanese Academy of Tokyo became a classic. The NRAO described his breakthrough

Nagaoka was impressed with the coincidence of height (~100 km) between the ionospheric layer and where visual meteors occur. Not only might meteors directly cause quick ionization, but he argued that long-lived fine dust resulting from disintegration of the original meteor particles would act as nuclei for collecting ions or electrons from the surroundings, thus causing a region of less ionization, or a "disturbance"

In 1931, Greenleaf Whittier Pickard made his own observations on the phenomena. He noticed that bursts of long distance propagation occurred during meteor showers. He published his paper "A Note on the Relation of Meteor Showers and Radio Reception" in July 1931.

 At about the same time Albert. Melvin Skellett a researcher at Bell Labs was theorizing a relationship between the kinetic energy of a meteor and the ionization of the ionosphere. Skellett spent 2 years testing his ideas with his colleagues. In November of 1932, during the Leonids meteor shower they tested the meteoric effect. More here. He assumed three crucial and correct details:

1. Meteors as a class could contribute, along with cosmic rays, the bulk of the energy needed to maintain charged particles in the ionosphere.
2. A large meteor could produce as many as 1,000,000 electrons and a critical mass of ions. (enough to effect radio) 
3. The variation in the strength of shortwave radio signals indicates turbulence in the ionosphere caused by the constant mixing action of the meteors.

The first signifigant attempt to use meteor scatter for anything useful was by the Communications Defense Centre in Canadia (CRC)  In the 1950s they launched project, "JANET."  It was code named JANET for Janus, the Roman god of the doorways, beginnings, endings and time. Janus is often depicted with two heads, facing opposite directions. I take that as a metaphor for transmission and reflection. In JANET they sent bursts of data when conditions were ideal trying to catch those short partial minute windows. to detect the window they broadcast a 90 MHz carrier wave and monitored it for sudden changes in strength.  They bounced signals from their radar research station in  Saskatchewan all the way to Toronto, a distance over 600 miles. The system was operational from 1955 until about 1960. The average character error rate was only 1.5 percent!  the Friends of CRC sumarized their data and bandwidth allocation:

"It may seem that the Janet technique was somewhat wasteful of spectrum space because of the relatively high instantaneous signaling rates which are required to achieve modest average information rates. This defect was offset by the fact that Janet systems, using the same frequency assignments, can be located much closer to each other than can other systems operating over comparable distances."

It is generally the case that frequencies between 50 to 80 MHz are ideal for meteor scatter communication. The FM band itself  (88.1 – 107.9 MHz) also works quite well. During meteor showers, laypeople can still perform basic experiments and get recognizable results. All you need is to know when the metoer showers are. Here's what fun to look for in 2011

• Quadrantids - January 3
• Lyrids - April 21
• Eta Aquarids -May 5
• Perseids - August 13
• Draconids - October 8
• Orionids - October 21
• Leonids - November 17
• Geminids - December 13

The Death of Smooth Jazz!

The common wisdom is that Smooth Jazz has been on the downhill slope for years now. WSJT in Tampa dropped it at the end of August.  107.7 WJCD in Norfolk dropped smooth jazz for oldies only 48 hours ago. Even stations in California, where the format did well historically are dropping smooth jazz as KKSF did in San Francisco last Summer. major markets like Philadelphia, New York and Chicago no longer have a Smooth Jazz station at all.  In September 1995 Billboard was describing Smooth Jazz as a format that could bump up a station's ratings:

"Shoring up sagging ratings plays a part in virtually every format flip, with station managers stepping back and anxiously hoping they have made the right musical move. That means there are a handful of happy programmers in Kansas City, MO, Honolulu, Norfolk, VA, Buffalo, NY and Washington DC who recently jumped to Jazz/AC where success has come quicker than imagined..."

Today it's more often described as rats leaving a sinking ship. But it's really all piffle without some statistics.  A stack of anecdotal articles does not amount to the end of a format. But the doom-mongering has been roiling for years.the articles have been almost universally negative, each pronouncing the death of a format that is  at very least still breathing at retail. Here's a sampling of the nay-saying.

The UTNE Reader (May of 2008)

"A Shallow Grave for Smooth Jazz"

Pop Matters (April 2008)

"R.I.P. Smooth Jazz 1985 - 2008"

Jazz Artistry (May 2010)

"So Now that Smooth Jazz Is Dead"

The deletion of the The Jones Radio network feed for "Smooth Jazz" in September of 2008 is usually considered the turning point. But the half-dozen stations using that feed all switched over to carry the Smooth Jazz satellite feed from Broadcast Architecture. All things considered, it wasn't much of a turning point, really more of a blip.  Wikipedia sums up the descent in a single sentence.  "...in 2007, the popularity of the format began to slide." Today we do the real math.

But as with all math there are caveats. I do not have exact dates for every smooth jazz flip that has occurred in the last decade. Rather than try to concatenate and sort the varied data points of varied reliability, I will use select data of known reliability focusing on the top 150 markets. It reduces the sample but that reduces my chances of introducing bad data which would skew my sample. The trend line here is logarithmic to avoid the drama of a facetious linear 0 point, but in all honesty, the difference is trivial.

The above data set runs for 6 years, from October 2004 to October 2010. What you see is a drop from 47 stations in the top 150 markets to a total of 18 in those same markets. While the markets that make up the top 150 have changed somewhat over that time window I think it's still a fair indicator for the trend line. Interesting also is that there is a noticeable plateau from September 2005 through April 2007, the total number varied over those 20 months but each time returned to about 40. Then it began the sharp fall into it's contemporary abyss. Yet even today this is not a dead format. The data set appears to be starting another plateau where it may sit for many more months or even dwindling years.