Re: WNTN (was WPTR)

[dan.strassberg@worldnet.att.net]

This is a pure guess because I don't know how strong the 
interfering signals really are. My guess is that 
interference-free service would extend to around the 25 
mV/m contour. I haven't run the numbers to see how far 
that would be from the TX, but probably two to three 
miles to the southeast, which means that most of Belmont 
and Watertown plus part of Arlington would receive a 
good signal. However, the signal would be listenable 
over a considerably larger area. When CBL was operating, 
my guess is that WJIB's nighttime interference-free 
contour might have gotten all the way to Fresh Pond 
Circle (1000 ft?). Yet people listened regularly over 
five miles away. You could hear the interference, yet it 
wasn't bad enough to scare off the listeners who wanted 
to hear the station. If a station transmitting from the 
1150 site with a pattern similar to WAMG's produced a 
listenable signal six miles to the southeast, the area 
in which a lot of people would be willing to listen 
would probably also include Allston and Brighton as well 
as parts of Cambridge and Newton. In fact, the pattern 
would be kind of a squashed (as well as smaller) version 
of WAMG's, because, at 1550, the towers are electrically 
further apart than they are at 1150. Especially if you 
want to limit radiation behind the array, the greater 
spacing leads to a fatter pattern--sort of like the 
pattern was a balloon and you pushed on the end opposite 
the point where you put in the air. If you look at 
WEEI's patterns you'll get the general idea. WEEI's 
towers are 120 electrical degrees apart. WAMG's are 80 
degrees apart. At 1550, the WAMG towers would be about 
108 degrees apart, so the pattern would be closer in 
shape to the WEEI patterns than to the WAMG patterns.

I'm assuming, of course, that the neighbors and the Town 
of Lexington would shoot down any proposal to construct 
additional towers at the site. If two towers could be 
added, to produce five equally-spaced towers, a power of 
several kW would be possible, and the pattern could be 
teardrop shaped--much more like WAMG's night pattern but 
with a good deal less radiation off the back of the 
array. This arrangement would not be ideal (towers would 
be spaced less than 54 degrees apart, which is 
considered close), but the design would probably be 
workable. The AM 860 in Philadelphia holds a CP for a 
five-tower in-line array quite like what I'm describing. 
My guess is that the Philly station is proposing to move 
two towers and increase from four towers to five to cut 
down on radiation to the northwest, which would enable 
them to get meaningful night power on the Canadian clear 
channel. The TX is 16 or 17 miles from downtown 
Philadelphia, and with all of the interference from 
CJBC, whatever night power is possible with the present 
four-tower array probably isn't sufficient.
 
> Just curious, what type of nighttime signal would be "as good as they could 
> get"? What type of coverage would that 500W get them? It sounds like it would 
> be counter-productive, since you said that a COL change would be needed (to 
> Belmont or Arlington), meaning their night signal wouldn't cover Newton 
> anyway. And how powerful could 500W on a graveyarder like 1550 be anyway?
> 
> -Sean