[BC] Real cases of IBOC interference wanted for research purposes

[RSTYPE@aol.com]

In a message dated 7/19/2006 3:27:32 PM Eastern Standard Time, 
paul at amtower.com writes:
believe the 1290 in Ann Arbor Michigan gets a lot of interference from
WXYT 1270's IBOC.  I think the same with the 940 in Lima OH, from 950 WWJ in
Detroit around Findlay Ohio.

Paul Smith

It appears to me that both of these cases have been blown way out of 
proportion (if something is repeated often enough it must be true).  

WLBY (1290) is not licensed to Ann Arbor.  It is licensed to Saline, to the 
southwest of Ann  Arbor and has the nulls of its directional pattern in the 
direction of Ann Arbor.  Contrary to what some here have claimed, it does not 
place its 5 mV/m contour over Ann Arbor, especially when one considers that the 
actual soil conductivity in the Ann Arbor area is less than the 8 mS/m value 
specified on the M3 map, even in the winter.  In a past life, I spent some time 
as a chief in Ann Arbor and distinctly recall that the station had a marginal 
signal in most of Ann Arbor.

Findlay is not located within the 0.5 mV/m protected daytime contour for WLJM 
(940) and is predicted to receive daytime interference to its groundwave 
service area in the Findlay area from the analog facilities of WWJ.  This 
situation existed long before WWJ implemented IBOC operation (and long before they 
improved their daytime operating facilities from 5 kilowatts nondirectional to 50 
kilowatts directional).  I also spent time in the distant past working in the 
Lima market and actually designed and tuned the presently licensed WLJM 
pattern.

One thing everyone needs to remember is that, even without IBOC, areas 
outside a station's protected daytime contour where it may presently have a 
"listenable" signal can, and always could, be lost to interference resulting from 
modifications and improvements to other station's analog facilities.

Roy Stype
Carl E. Smith Consulting Engineers