ABUS34

["Lorraine Smith" <smithl@alden.com>]

     I thought some of you dx'rs might be interested in this item...
     
     Lorraine
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PUBLIC INFORMATION STATEMENT
NATIONAL WEATHER SERVICE LAKE CHARLES LA 
1110 PM CDT THU JUL 10 1997
     
...VERY GOOD RADIO/TELEVISION RECEPTION EXPECTED TONIGHT...
     
CLEAR SKIES OVER MUCH OF THE REGION IS LEADING TO GOOD RADIATIONAL 
COOLING OF THE EARTH'S SURFACE TONIGHT. THIS COMBINED WITH WARMING
AT AROUND 5000 FEET ABOVE GROUND LEVEL IS LEADING TO WHAT IS KNOWN AS 
A TEMPERATURE INVERSION...MEANING THAT TEMPERATURE INCREASES WITH 
HEIGHT ABOVE THE SURFACE INSTEAD OF THE NORMAL REGIME OF DECREASING 
TEMPERATURES WITH HEIGHT. THIS CAUSES RADIO WAVES TO BEND SHARPER 
THAN NORMAL TOWARDS THE GROUND...IN SOME CASES BOUNCING ALONG THE 
SURFACE FOR MUCH GREATER DISTANCES THAN WHAT WOULD OTHERWISE
OCCUR. THE PHENOMENA ENDS WITHIN AN HOUR OR TWO AFTER SUNRISE AS 
SURFACE TEMPERATURES RISE AND TEMPERATURES ONCE AGAIN BEGIN TO 
DECREASE WITH HEIGHT.
     
WHAT THIS MEANS IS THAT RADIO AND TV RECEPTION FROM FURTHER DISTANCES 
WILL BE FAIRLY CRISP TONIGHT...IN SOME CASES OVERWHELMING CLOSER 
SIGNALS. FOR EXAMPLE...IN LAKE CHARLES THIS WOULD MEAN PICKING UP 
STATIONS FROM HOUSTON AND BATON ROUGE RELATIVELY EASILY WHILE SOME
OF THE LOWER POWER STATIONS IN THE AREA WOULD BE OVERWHELMED BY THOSE 
STATIONS MUCH FARTHER AWAY. HAM RADIO OPERATORS WILL ALSO BE ABLE TO 
REACH FURTHER DISTANCES THAN NORMAL...ABLE TO CONTACT PERSONS NOT 
NORMALLY WITHIN THEIR RANGE.
     
THIS PHENOMENA IS MUCH MORE COMMON IN WINTER MONTHS...SO ENJOY A MID 
WINTER TREAT...AND BASK IN THE GREATER VARIETY OF TV AND RADIO SIGNALS 
OUT THERE OVERNIGHT.
     
     

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