On 14 Jun 2004 04:22:21 GMT, "David Eduardo"
wrote:


But you are concened about the damage to the local signal, not the abilty to
hear an AM hundreds of miles form its city of license.

With 5kw we're not expecting a usable signal hundreds of miles away
from the COL. But we are concerned about more than our metro coverage
area.


There is also some evidence that IBOC interference can affect home
metro groundwave coverage of adjacent channel stations.

But not much. I can listen to the 1050 in the Riverside market within 10
miles of the KTNQ 50 kw IBOC site.


I certainly hope so, since they are 30 kHz apart. But there is a real
problem with first-adjacent channel interference. I reference a
statement submitted by Clear Channel SVP/Engineering Jeff Littlejohn
to the National Radio Systems Committee regarding a test involving
WTOP, Washington (1500) and WARK, Hagerstown, MD (1490). Daytime
interference from WTOP's digital signal was found to be "significant"
at WARK's protected 0.50 mV/M contour, and "noticeable" at its 0.75
mV/M contour.
The full report can be found at
http://www.am-dx.com/clearchannelrprt.pdf

Mark Howell