[BC] Tower Location Change For WLAN 1390

[RichardBJohnson at comcast.net]

Yes. In the days when Part 15 was created, circa 1960, the around-town distribution was 2300 volts! Then, using the same wires and same insulators, the distribution was upped to 4200 volts! There was some interference when the insulators got wet so some "double petticoat" insulators were developed to replace the troublesome ones. Then, using the exact same wires and these new insulators, the distribution voltage was upped to 14 kV! Now, new installations use a four-wire three-phase group, the top being ground (not neutral), sometimes run through trees: http://2.bp.blogspot.com/_xzFgCqavcFI/SVWdW92n7jI/AAAAAAAAAQ8/UUdwcQ8Ictk/s1600-h/WiresTrees.jpg

The result being that there is no way that any Part 15 regulations are observed. Furthermore, I have been told by electrical distribution design engineers that the current design requirements are for equal corona and copper (resistive) losses. This is considered to be "optimum."

That, in a nutshell, is why AM radio is going away. Creating more sensitive radios will only cause their AGC circuits to suppress the sensitivity because the typical background noise from corona is now about 200 uV at the antenna input. In the '50s, AM's heyday, AM background noise was 5 to 10 uV.

Cheers,
Richard B. Johnson
Book: http://www.AbominableFirebug.com/

----- Original Message -----
From: "Ron Youvan" <ka4inm at tampabay.rr.com>

<snipped...>

I believe 100% of the 4,200 Volt distribution circuits (to all pole mounted transformers) have been 
replaced with 14 kV circuits.

-- 
Ron KA4INM