[HCDX] Don't shortchange your shortwave

["Zacharias Liangas " <greekdx@xxxxxxxxx>]

and just a news from mainstream media . mno comments 

Don't shortchange your shortwave

By Chris Handy
www.dailytexanonline.com/news/2007/07/23/Opinion/Dont-
Shortchange.Your.Shortwave-2926149.shtm

Shortwave radio is an excellent medium for keeping tabs on global 
events. Signals can be received from around the world at absolutely no 
cost to the listener, with a wider range of content than most local radio 
programming. Shortwave transmitters can be operated at a relatively 
low cost by organizations or even individual hobbyists, lending 
shortwave a freedom of expression unparalleled by mainstream media. 
In addition, the multilingual and multicultural content of shortwave 
fosters the development of a great diversity of perspectives. "DX'ing," 
or distance listening, is a rewarding hobby with little overhead required.

Despite being more affordable and easier to access than ever before, 
many people are completely unaware that shortwave exists. Technical 
considerations have also given a certain stigma to shortwave as difficult 
to use. The high frequency waves (3 megahertz to 30 megahertz) are 
too high to be picked up on an ordinary AM radio, requiring the 
purchase of special equipment. Sound quality is almost never as stable 
as local transmissions, and shortwave transmissions even have a 
tendency to drift to neighboring frequencies with changes in the 
weather.

But the close relationship between shortwave signals and the weather 
is the medium's greatest feature. What we call shortwave is simply a 
range of frequencies within the larger set of all electromagnetic 
radiation, which includes all other types of radio, as well as visible light, 
X-rays and microwaves. Signals in the shortwave range have a peculiar 
tendency to be reflected by our planet's ionosphere, a layer of gases 
extending from 50 to 600 miles above Earth's surface. Instead of 
beaming directly out into space, a shortwave signal sent from Earth at 
the proper frequency and angle will reflect back toward the planet's 
surface, where it can be received at another location.

By modifying the frequency and transmission angle, a shortwave 
transmitter can send signals to literally any point on the planet. Because 
the transmission relies on natural weather conditions rather than 
commercial satellites, there is no fee to receive the transmissions. 
Anyone wishing to receive a broadcast need only set up a suitable 
antenna and find the proper frequency.

The same atmospheric properties that keep shortwave listening free 
also prevent it from being commercially viable. Sound quality tends to 
be poor and is best suited to voice-only broadcasts, like the news. 
Sunspots and other cosmic events that interact with Earth's 
atmosphere can also interfere with shortwave transmissions. Time of 
day, season, temperature, cloud cover and other factors can all change 
the reception of any particular signal quite dramatically.

Yet shortwave continues to remain popular and is in many ways 
growing in popularity. A sturdy low-end receiver can be purchased for 
$150 or less, allowing full reception of the entire shortwave frequency 
range. Newer computer-controlled receivers make the task of finding 
signals much easier by providing scanning functions and visual maps of 
current planetary weather conditions. Some bold-hearted and 
technically inclined users even build their own receivers.

Many DX'ers enjoy listening for the quirky eccentricities of the 
shortwave spectrum, which carries a variety of unusual and often 
unidentifiable transmissions. Particularly intriguing, for example, are 
"number station" broadcasts, during which a voice reads out long 
strings of numbers, with no explanation of their purpose and no 
identification of the transmitter. Some people think these transmissions 
are coded instructions for international spies. Other signals to listen for 
include weather satellites and ham radios. Natural phenomena, such as 
the aforementioned sunspot activity, can also be received and studied, 
allowing the shortwave receiver to function as something like a low-end 
radio telescope.

Handy is an Asian cultures and languages graduate student.


http://zlgr.multiply.com (raidio monitoring site plus audio clips )
http://www.worldisround.com/articles/302315/ (Litohoro) 321199/Tinos 
http://www.flickr.com/photos/zachgr    pictures upload 
.
on my main : www.geocities.com/zliangas 
-tty-px.html : test of various TTY programs
-ethics.htm    : greek ethics , days and institutions 
-frape.htm: the greek way of cofee !!! 
Zacharias Liangas , Thessaloniki Greece 
greekdx @ otenet dot gr  ---  
Pesawat penerima: ICOM R75 , Lowe HF150 , Degen 1102,1103,108,
Tecsun PL200/550, Chibo c300/c979, Yupi 7000 
Antenna: 16m hor, 2x16 m V invert, 1m australian loop 


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