Wait a minute, let me get my lawyer out of the closet.
73, Dick, W1KSZ> Date: Sat, 14 Feb 2009 17:16:36 -0500> From:
jimjarvis@optonline.net> To: towertalk@contesting.com> Subject: Re: [TowerTalk]
antennas and towers near broadcast stations> > > Bottom post... see below:> >
(edited for space...)> Message: 6> Date: Fri, 13 Feb 2009 20:47:25 -0600> From:
"Its from Onion" <aredandgold@msn.com> Subject: [TowerTalk] > Antennas and
towers near broadcast stations> > The FCC has without much notice in Amateur
circles passed was: > "quietly snuck," a poor choice of words, a Rule that will
affect non- > broadcast radio licensees including Radio Amateurs.> excerpt:> >
Quote:> ?1.30002 Tower construction or modification near AM stations.> (a)
Construction near a nondirectional AM station. Proponents > of construction or
significant modification of a tower which is > within one wavelength of the AM
station, and is taller than 60 > electrical degrees at the> AM frequency, must
notify the AM station at least 30 days in > advance. The proponent
shall examine the potential impact of the > construction or modification as
described in paragraph (c). If the > construction or> modification would
distort the radiation pattern by more than > 2 dB, the licensee shall be
responsible for the installation and > maintenance of any detuning apparatus
necessary to restore proper > operation of the> nondirectional antenna.> (b)
Construction near a directional AM station. Proponents of > the construction or
significant modification of a tower which is > within the lesser of 10
wavelengths or 3 kilometers of the AM > station, and is taller than 36
electrical degrees at the AM > frequency, must notify the AM station at least
30 days in advance.> The proponent shall examine the potential impact of the >
construction or modification as described in paragraph (c). If the >
construction or modification would result in radiation in excess of > the AM
station's licensed standard pattern or augmented standard > pattern values, the
licensee
shall be responsible for the > installation and maintenance of any detuning
apparatus necessary to > restore proper operation of the directional antenna.>
(c) Proponents of construction or significant modification of > a tower within
the distances defined in (a) and (b) herein of an AM > station shall examine
the potential effects thereof using a moment > method analysis. The moment
method analysis shall consist of a model > of the AM antenna together with the>
potential reradiating tower in a lossless environment. The > model shall employ
a simplified version of the methodology specified > in ? 73.151(c) of this
chapter. The AM antenna elements may be > modeled as a Federal Communications
Commission FCC 08-228 series of > thin wires driven to produce the required
radiation pattern, without > any requirement for measurement of tower
impedances.> (d) A significant modification of a tower in the immediate >
vicinity of an AM station is defined as follows:> (1) Any change that
would alter the structure's physical > height by 5 electrical degrees or more
at the AM frequency.> (2) The addition of one or more antennas or a
transmission > line to a tower that has been detuned or base insulated.> (e)
The addition or modification of an antenna or antenna > supporting structure on
a building shall not be considered significant.> (f) With respect to an AM
station that was authorized pursuant > to a directional proof of performance
based on field strength > measurements, the proponent of the tower construction
or modification > may, in lieu of the study described in paragraph (c),
demonstrate > through measurements taken before and after construction that
field > strength values at the monitoring points do not exceed the licensed >
values. In the event that the pre-construction monitoring point > values exceed
the licensed values, the proponent may> demonstrate that post-construction
monitoring point values do > not exceed the pre-construction values.> Al
ternatively, the AM station may file for authority to > increase the relevant
monitoring point value after performing a > partial proof of performance in
accordance with ? 73.154 to establish > that the licensed radiation limit on
the applicable radial is not > exceeded.> (g) Tower construction or
modification that falls outside the > criteria described in the preceding
paragraphs is presumed to have no > significant effect on an AM station. In
some instances, however, an > AM station may be affected by tower construction
notwithstanding the > criteria set forth above. In such cases, an AM station
may submit a > showing that its operation has been affected by tower
construction or > alteration. If necessary, the Commission shall direct the
tower > proponent to install and maintain any detuning apparatus necessary to >
restore proper operation of the AM antenna.> >
LINK<http://fjallfoss.fcc.gov/edocs_public/attachmatch/FCC-08-228A1.pdf>> > A
vertical resonant at 1.8 MHz is 81
degrees tall at 1.6 MHz and > would be if not detuned at the BC frequency
forbidden within 2 miles > (approx) (or 10 wavelengths at its frequency if
less) of a > directional AM station. An 80 meter vertical falls to it as well,
as > well as many shorter towers according to their electrical length.> >
Considering the impact the unnoticed Part 73 action has had in > Amateur
circles, a reconsideration could be in order if only to > accept our comments.>
-0-> > 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 li
censed 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 affect
ing> 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.> >
N2EA> Jim Jarvis, MBA, President> The Morse Group, LLC> www.themorsegroup.net>
Leadership and Supervisory Development * Strategic Planning * > Corporate
Coaching> > > > _______________________________________________> > > >
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