[BC] Faraday Fence - No Foreign Signals Allowed

[PeterH]

On Feb 18, 2010, at 9:41 AM, George Brand wrote:

> Of course the most famous CANADIAN border blaster would have to be  
> CKLW.

That:s certainly the most prominent example.

The Big 8:s day pattern was designed to cover Detroit and Toledo,  
with some deference being given to Cleveland and parts of Indiana,  
but it also had to protect Montreal, about which I will explain later.

The Big 8:s night pattern removed the lobe towards Toledo, thereby  
providing the required protection to Mexico, which is the actual I-A,  
in Juarez. The power had to go somewhere, so this improved service to  
Detroit and to Cleveland, with a good quality signal finally reaching  
that city, and then on to Buffalo.

The other true border blaster is also on 800, Montreal:s CJAD,  
operated by an English-speaker with religious interests.

CJAD:s array is four widely-spaced towers each of which are 195  
degrees tall, the ideal height for a Class A, but this station is a  
Class B.

The towers are driven somewhat similarly day ... 50 kW ... and  
night ... 10 kW, with the pattern being the multiplication of a three- 
leaved clover with a preference for Montreal, and one unwanted leaf,  
towards Mexico. This is multiplied by a figure-8 which accomplishes  
two things ... first, it enhances the radiation towards Montreal ...  
important especially for night operation with 10 kW ... and it  
cancels radiation towards the Class B in Quebec City and towards the  
Class A in Juarez, Mexico. This effect also reduces interference to  
WGY in Schenectady, which, as a Class A, must also be protected as it  
is plus 10 kHz from CJAD.

One might ask, what happened to the third lobe of the three-leaved  
clover?

Well, it saturates the New England area of the United States.

In the Northeast, the dominant station, although it is also a Class  
B, is the one in Quebec city, and CKLW and CJAD both protect that  
station, as do the two 800s which were eventually dropped-in, between  
CKLW and CJAD.