Directional ex-Class IA AMs

[Dan.Strassberg]

Back in the day. there were four Class IA clear-channel stations that
operated DA-1 (same facilities day and night): WBZ, WWL, WEAF (now
WFAN), and WTAM. Of those, two remain directional. In all cases,
really, the reason for directionalizing was the same, not to protect
any station but to send the signal over land (where people live) and
not waste it over water (where only fish and a smaller number of
crustaceans live).

In WBZ's case, the water is the Atlantic Ocean to the east; in WWL's
case, it is the Gulf of Mexico to the south; in WEAF's case, it was
Long Island Sound to the east; and in WTAM's case it was Lake Erie to
the north. Of these four stations, WBZ is the most directional (sends
the least signal--the equivalent of ~1 kW ND--over Mass Bay). WWL
sends something approaching the equivalent of 5 kW ND to the south; I
don't know why. I have never seen WTAM's or WEAF's patterns. but my
understanding is that neither of these stations (both then owned by
RCA/NBC) was strongly directional.

WEAF's transmitter was in Port Washington on Long Island's north shore
in Nassau County, a pretty good distance from mid-town Manhattan. The
signal was boosted to the west to level the playing field with New
York's other Class IA clears, WJZ 770, which transmitted from New
Jersey (I think it was Bound Brook until the 1943 move to the current
Lodi site) and WABC 880. (For those who don't remember that far back,
the WABC calls were on 880 until, I think, 1943. 880, then as now, was
on an island east of the Bronx in Long Island Sound--but it was a
different island back then.) WEAF's signal to the east over Long
Island and Connecticut was pretty potent--I've heard the equivalent of
25 kW ND, but I can't verify that.

As for WTAM, there was a significant potential audience in Ontario, 50
miles or so across Lake Erie. Also, the transmitter itself may have
been south of downtown Cleveland. The antenna was quite unusual for a
US station. The designer, the legendary Carl Smith, used a technique
that has been used successfully in Mexico and Europe but was never
popular with the FCC. It was a one-tower, two element, DA. The tall
uniform cross-section, guy-supported tower was, of course, one of the
elements. The second element was a wire dropped from one of the
supporting guys, resulting in unequal element heights and rather close
spacing between the elements. Neither of those characteristics was a
killer and, indeed, those characteristics are shared by many current
two-element DAs constructed of two conventional towers. I remember
seeing a polar plot of the WTAM pattern. It was not very directional
and the radiation efficiency was HUGE--much higher than that of WTAM's
current conventional half-wave tower. I don't know the height of the
old tower; presumably, it was more than helf wave--maybe as much as
5/8 wave.

There were other Class IA AMs that might have benefitted from using
DAs but never chose to do so. The most notable was KFI, which, back in
the '30s, could have built a two-tower array (or even a one-tower
setup like WTAM's) on Catalina Island. I suspect, however, that KFI's
owner, auto dealer Earl C Anthony, figured that the publicity from
having the station's 750' tower right next to his auto dealership was
a good trade-off for the coverage KFI could have gained in southern
California's then-sparsely populated desert areas. Also, there might
have been problems with getting the audio to a transmitter "26 miles
across the sea." I don't know in what year Pacific T&T installed its
first undersea cable between Santa Monica and Avalon.

As for what stations the directional operations protect, although that
was not an issue when any of these ex-IA stations was built, changes
in the FCC rules might make it an issue now if WBZ or WWL wanted to
abandon its DA-1 operation. WBZ's radiation toward a station in Puerto
Rico might become an issue if WBZ wanted to operate ND. And I believe
that there is now at least one full-time station on 1030 in Florida.
WWL's limited radiation to the south now protects several signals in
(I believe) Venezuela and surrounding countries.

-----
Dan Strassberg (dan.strassberg@att.net)
eFax 1-707-215-6367

----- Original Message ----- 
From: "A. Joseph Ross" <joe@attorneyross.com>
To: "Dan.Strassberg" <dan.strassberg@att.net>
Cc: "Boston Radio Group" <boston-radio-interest@lists.BostonRadio.org>
Sent: Monday, November 23, 2009 12:30 AM
Subject: Re: UHF in Southern New England (was WHNB/WVIT Channel 30
(was Re:WTAG-TV?))
>
> Why does WBZ have a directional signal at all?  What do they have to
> protect?
>
> -- 
> A. Joseph Ross, J.D.                           617.367.0468
> 92 State Street, Suite 700                   Fax 617.507.7856
> Boston, MA 02109-2004                    http://www.attorneyross.com
>
>