Re: [IRCA] More IBOC In Philly

["Tim Kridel" <tkridel@xxxxxxxxx>]

Regarding "under the old rules a signal of 25 mV/m was required over your
downtown area," how was that measured? I ask because I assume that the
signal strength will vary significantly around the concrete canyons of a
major downtown. If that's correct, is an average or something else used?
Just curious.

-----Original Message-----
From: irca-bounces@xxxxxxxxxxxxxxxx [mailto:irca-bounces@xxxxxxxxxxxxxxxx]
On Behalf Of Rene Tetro
Sent: Friday, September 23, 2005 3:50 PM
To: 'Mailing list for the International Radio Club of America'
Subject: Re: [IRCA] More IBOC In Philly

David,

I would suggest you check out the FCC Allocation Rules.  Most radio stations
are protected to their 0.5 mV/m contour.  Class A stations - like WABC,
WCBS, etc - are protected even more - out to their 0.1 contour.  0.5 mV/m
is, and always has been considered to be a station's "primary" coverage
area, and is the contour used on most coverage maps.
This, of course, does not mean you're going to get a perfect signal at these
levels; it means that no other stations are allowed to cause interference
within that contour.  (We are, of course, talking daytime.
Nighttime is a whole different ball game).

Read FCC rules section 73.182 at
http://a257.g.akamaitech.net/7/257/2422/12feb20041500/edocket.access.gpo
.gov/cfr_2004/octqtr/47cfr73.182.htm

City grade contour is something entirely different.  A station is required
to put 5.0 mV/m over their city of license.  Most put much more, and under
the old rules a signal of 25 mV/m was required over your downtown area.

73,
Rene'



On Friday 23 September 2005 11:53, David Gleason wrote:
> I don't think a 0.5 contour is primary. The primary is 5 mvm, I
believe
> and the city grade is 25 mvm if I remember the definitions correctly.
In
> most urban areas, a 5 mvm contour will not produce much listening; 
> consensus is that it takes about 10 mv/m or better to generate AM 
> listening.




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