[BC] WKOX site

[RichardBJohnson@comcast.net]

I can't beleive I read this!

 > anything good for the way an AM station gets out, but I suspect that the
 > effects of such trees are generally rather minor. So the root system breaks
 >

You really should browse
http://ecfr.gpoaccess.gov/cgi/t/text/text-idx?c=ecfr;sid=a0586f92fff9cf0b57d53c4c7c2ce042;rgn=div6;view=text;node=47%3A4.0.1.1.2.1;idno=47;cc=ecfr

In particular look at at the math in 73.150 then, without crossing 
your fingers, claim with a straight face that they have anything to 
do with an antenna system in a forest. I am not the FCC. Both you and 
me are the "owners" of the radio frequency spectrum. Stations obtain 
a license to use "our stuff" providing, amongst other things, that 
they comply with good standards of engineering practice.

As an engineer with some considerable training in electro-magnetics 
and electrostatics, I can assure you that any lossy material within 
the immediate field of an antenna will dissipate radio frequency 
power. That's why there was a requirement for a ground-screen in 
addition to ground-radials near the base of the tower. The 
electrostatic field is high there. You are not supposed to even let 
grass grow there! A single radiator, in its simplest form, is a 
series inductor, capacitor, and resistor. The resistor is the 
radiation resistance (fixed by physical things having to do with 
electrical height) and parasitic (loss) resistance having to do with 
grass, tall weeds, items that can absorb and re-radiate such as 
light-wires, and ... trees. When Don Howe, (retired from WPI at 90, 
now diseased) invented directional antennas for broadcast use, he 
would never have thought that anybody would have trees anywhere near 
a directional antenna site!

I see just too much of his work thrown away. His first directional 
array was WRMS (yes root-mean-square). It eventually became WARE on 
Coy Hill, in Warren. His second was WORC in Worcester. Both of these 
stations are in worse shape than WKOX that somehow you are trying to 
defend. WKOX was just an easy-to-find (on the web) example of 
transmitter site neglect.

A problem with AM transmitter site neglect is that even if 50 percent 
of the power is dissipated by trees, it will hurt the signal strength 
only 6 dB. This just might make you think that the trees don't hurt 
anything. They do. They propagate poor engineering.

--
Cheers,
Richard B. Johnson


  -------------- Original message ----------------------
From: "Dan Strassberg" <dan.strassberg at att.net>
 > Richard Johnson objected to my complaints about the arial photo of the WKOX
 > array.
 >
 > I never said that the photo misrepresented the location of the trees
 > relative to the towers. But the photo DOES give a decidedly false impression
 > about the orientation of the array. And BTW (you must know this; you work
 > for Analogic, so presumably you are in the Boston area), the array now
 > serves three stations (WKOX--until it moves to Newton later this year, at
 > which point CCU will probably license the Mt Wayte site as an auxiliary for
 > WKOX, WBIX (days only but two patterns), and WSRO. I believe the major
 > factor affecting the conformance of the three measured patterns (two for
 > WBIX, one for WKOX) with the corresponding standard patterns is the tall
 > smoke stack at the Framingham Municipal Incinerator across Mt Wayte Ave on
 > the north side of the property. (Must be beyond the edge of the photo.) That
 > stack must have a greater effect on the patterns than that of all of the
 > trees in the photo combined. Of the three patterns, only WBIX's CH pattern
 > has any augmentations and that pattern is augmented in the region of its
 > minimum to the south, suggesting that the smoke stack to the north probably
 > does reradiate the signal. Moreover, the installation of the WBIX array
 > about five years ago involved some first-class engineering people. If they
 > felt that the patterns were affected in any important way by the trees, you
 > can bet that they would have gotten CCU to clear the trees--unless the Town
 > of Framingham objected--a definite possibility.
 >
 > I can't believe that trees growing in the middle of the ground system do
 > anything good for the way an AM station gets out, but I suspect that the
 > effects of such trees are generally rather minor. So the root system breaks