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Re: [TowerTalk] antennas and towers near broadcast stations

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Subject: Re: [TowerTalk] antennas and towers near broadcast stations
From: "D.Calder" <>
Date: Sun, 15 Feb 2009 06:11:55 -0500
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"Then, we had to repeat the proof of performance, which entailed almost $20k
in labor, plus a consulting engineer's fee of 14k."

Who did your work? I have to get pre and posts studies done every day for
our cell sites and they are approx $1200 each.
I don't pay 20k for a de-tuning kit install, little alone to get a study
done! Maybe you need a name thrown your way.

Every time a new carrier installs on one of our cell sites within the
required distance of the AM station we need
to get it done. The tower could be there for years. If they even change
antennas, we need it done.

Jim is right though, it's not unreasonable. It's meant for companies I work
for. You can't change the AM's pattern.
I have never known a ham to effect an AM stations pattern. I know some that
live REAL close with steel in the air beside

73 Dave

Dave Calder

N2EA Comments:   This is perfectly reasonable, on its face.    
Commercial interests bear the responsibility of assuring
that their construction... towers or power lines, for example... do  
not impact the pattern of a directional array AM station.
The cost of re-certifying a directional array... repeating the proof,  
is something on the order of $20,000,  in today's dollars,
before you add in the consulting engineer's fees.    Been there, done  
that, as they say.   4 times, in fact.

I had a 4 tower AM station go out of licensed Field Strength  
parameters, and had to operate on waivers, for
over a year, until we identified a high tension line at 2 miles  
distant as the offending construction.   Lawsuit
followed.   It was $100k legal fees, out of pocket, until the utility  
in question lost, paid up, and detuned their towers.
Then, we had to repeat the proof of performance, which entailed  
almost $20k in labor, plus a consulting engineer's
fee of 14k.

Like the idea that amateurs should be exempt from stupid driving  
while distracted by our radios, we are not exempt
from causing inadvertent harm to commercial operations by our  
construction.  Much as we might like it to be otherwise.
Thoughtful consideration is in order, with all we do.   (Like  
climbing safely!)

I think the real concern here is cell towers, not us,  just to be  
practical.   Oh,  and just to crank a few numbers,
a wavelength at 1 MHz is 936'.   10 wavelengths is 1.8 miles.    At  
1.5Mhz, that's 1.2 miles.   Odds of us affecting
them at that distance are quite small.   But why should we be exempt,  
if we cause harm?

If we make a vertical resonant on our operating frequency, it is, de- 
facto, non-resonant at the broadcast freq.
i.e.  decoupled.    And we shouldn't have to worry.

Unreasonable rule making?   I don't think so.

Jim Jarvis, MBA, President
The Morse Group, LLC
Leadership and Supervisory Development * Strategic Planning *  
Corporate Coaching


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