[PPRAANet] Fwd: Solid state navigation devices... may substitute for radio these days, except for cloudy days.

[Glenn]

     "PRE" GPS days!!!
     Glenn   n3ulw
*An interesting bit of USPS history...*
**
All over the USA, seventy foot concrete arrows can be found in remote 
locations. Follow them, and they’ll point you out of the desert.
01-giant-arrows
They come courtesy of the US Postal Service’s Air Force and will point 
you all the way across the continental United States.
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They were constructed in 1924 to guide postal planes in the right 
direction as they carried mail from coast to coast.
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These old planes couldn’t rely on radio as much at the time, so they 
used these arrows, along with beacon towers, to navigate.
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05-giant-arrows
The arrows and beacons bisect the United States from San Francisco to 
New York City.
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The towers were 50 feet tall and fixed with gas lights that could be 
seen from 10 miles away, in order to help lost pilots find their way.
This is a model of the arrows and towers in their heyday.
07-giant-arrows
World War II brought new advances in radio technology that effectively 
made the towers and arrows system obsolete.  The towers were mostly 
dismantled.
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There has been an effort to restore and preserve some of them, however. 
Like this one in New Mexico complete with its generator shack.
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This is a pretty cool piece of history, even if it was short lived. To 
think of those early postal pilots navigating like this from coast to 
coast is mind blowing.