Re: 1200 in Meffa

[Dan Strassberg <dan.strassberg@worldnet.att.net>]

At 06:28 PM 11/17/98 -0500, you wrote:
>>Be interested in seeing (WKOX's new) pattern, since 1230 in Salem must be
>protected.
>
>Bob...are you sure a station on 1200 has to protect all the way down to
>1230?  What's the cutoff point?  I imagine 50kW nondirectional would
>certainly pose a problem to WESX's metro Boston signal...but then, Boston
>isn't WESX's COL...and in its class, does it warrant protection?
>
Absolutely. No overlap of 25 mV/m ground-wave contours on the third-adjacent
channel. I find it hard to believe that there is any way that WKOX,
transmitting 50 kW from Medford, could possibly avoid prohibited overlap
with WESX. WESX's 25 mV/m contour very likely hits Boston (Dorchester),
because the path from Salem (the city in MA, that is, not the Christian
broadcasting company) to Dorchester is over salt water all the way. If the
distance is 25 miles or less (and I think it is), there is almost certainly
an overlap problem. WKOX might be able to create a daytime pattern that
would protect WESX, though. (Seems unlikely but maybe.) For sure, doing so
would reduce the signal strength over Boston. At night, WESX may not be a
problem because WESX, as a Class C AM, has no protected nighttime service
area. And then there's critical hours (the two hours after sunrise and
before sunset). If WKOX sends too much signal toward San Antonio TX (home of
WOAI, the dominant Class A station on 1200), WKOX will cause interference
within WOAI's protected service area. That could mean that WKOX would have
to reduce power during CH.

Although the WNRB site in Waltham is patently lousy from a soil conductivity
standpoint, it might be WKOX's best bet. The site is far enough from
Dorchester Bay that a simple pattern could probably provide the necessary
protection to WESX. Whereas WNRB has no towers on an east-west line (an
arrangement that is part of WKOX's current proposal and is also a
characteristic of the 590 array) the WNRB array could probably be made to
work for WKOX at night as well. You can do a lot with four towers in the
parallelogram configuration of the WNRB array. However, if it were necessary
to install new transmission lines, the cost would skyrocket. The lines are
buried deep (maybe 30 or 40 feet below ground level) and are covered with a
parking lot and buildings. Moreover, remediation of interference caused by
another 50-kW station at that site could cost several fortunes. The WNRB
site is in the middle of a densely populated area.

As far as the night service that WKOX would provide to most of greater
Boston from Wellington Circle, for the most part, (as they say in New York)
fuhgeddaboudit. You live in Florida, Shel, so you may never have heard
WXKS's night signal. Come to think of it, most of us around Boston have
never heard it either. WXKS has a pattern similar to WKOX's proposed night
pattern (a cardioid aimed east, deep null to the west). WKOX's 50 kW would
help (WXKS is only 1 kW at night), but interference-free night service would
still extend only about as far west as Somerville.

- -------------------------------
Dan Strassberg (Note: Address is CASE SENSITIVE!)
ALL _LOWER_ CASE!!!--> dan.strassberg@worldnet.att.net
(617) 558-4205; Fax (617) 928-4205

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End of boston-radio-interest-digest V2 #234
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