[BC] Documented harmful interference

[Phil Alexander]

On 21 Jan 2006 at 14:56, Barry McLarnon wrote:

> Huh?  What's "secondary" got to do with it?  Secondary coverage refers to 
> nighttime skywave coverage, and is therefore irrelevant in this context.
> The primary daytime coverage of a Class A station is protected to its 0.1 
> mV/m contour against co-channel interference, and to its 0.5 mV/m contour 
> against adjacent channel interference.  Period.

Yet a Class A station cannot de jure render primary service unless its 
signal strength exceeds the levels stated below. Thus I misused the
term "secondary" referring to the protected area (within 100 uV/m, but
outside 500 uV/m) where primary service cannot be rendered, as a matter
of definition, to a community. Essentially all the geography of the
area in question falls within "community" boundaries. AFAIK the entire
state of Massachusetts is divided into cities and towns and the same
situation, or very nearly, exists in Connecticut. 

> > 73.182(d) further defines, "The groundwave signal strength required to
> > render primary service is 2 mV/m for communities with populations of
> > 2,500 or more and 0.5 mV/m for communities with populations of less than
> > 2,500.
> 
> Also not relevant in this context.  This deals with minimum levels of 
> service, not interference protection per se.

If a station cannot provide the minimum level of service established by
the rules, how can it be interfered with de jure?

> > Thus, it appears WTIC would have to show objectional interference as
> > defined by relative signal strengths within their 0.5 mV/m contour in
> > a town having a population of less than 2,500, or within their 2.0
> > contour in one more than 2,500. Based on such a showing, the FCC might
> > grant relief, or depending on the next report and order, a higher
> > threshold may be set. Realistically, they will probably have to show
> > that WILD exceeds the NRSC-5 mask within their primary service area
> > before anything is done about it.

The part of the above that may not be obvious is that, as above, there is
essentially NO land in the area in question that is not within city or
town boundaries.

> The COL stuff should not really enter into the equation... a protected 
> contour is a protected contour, no matter where it lands.  Granted, you 
> may not get very far complaining about interference in an area inside that 
> contour that is largely uninhabited.

There are many FM rimshots into metro areas from surrounding "local" (Class A)
stations. I seriously doubt their complaints of interference within the metro
area that they are NOT licensed to serve will get much consideration. IOW, if
the area in question is outside their 60 dBu I suspect a deaf ear will be
turned. AM's cannot expect better treatment although their situation is
somewhat more complex.

See the language of 73.182(a)(1) vs. 73.182(a)(2) vs. 73.182(a)(3). Having
created the mess, it would appear reasonable if the FCC tries to construe the
application of the word "service" as narrowly as possible. The FCC will have
more meritorious complaints before it as the pattern bandwidth factor comes
into play.

<snip>
> 
> Let the litigation begin!

If it does, there is a strong possibility it will be vs. the FCC by an
applicant for a NEW station based on 73.182(b)


Phil Alexander, CSRE, AMD
Broadcast Engineering Services and Technology 
(a Div. of Advanced Parts Corporation) 
Ph. (317) 335-2065   FAX (317) 335-9037





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