Boston downtown radio towers (1956)

[Dan.Strassberg]

KTLK (1150) is diplexed with KTNQ (1020). Both stations run 50 kW-D. KTNQ
also runs 50 kW-N KTLK's night power is very close to 50 kW (44 kW, IIRC).
There are five towers at the site. Both stations use all five by day. KTLK
also uses all five at night. KTNQ uses four towers at night. The towers are
quite tall--180 degrees at 1020 (480'), which makes them 203 degrees at
1150.

When the KTNQ array was built, it was not a rooftop setup. It still isn't
exactly a rooftop setup. What happened was that the land around the towers
was sold and a large one-story warehouse was built around the tower bases
and beneath the guy wires. The ground system was relocated upward by
approximately 18' (the height of the building) to the warehouse roof. Each
tower base is in a sort of well in the roof. I'm guessing, but the wells are
probably close to 20' square. The ground radials for each tower run down the
sides of the well and converge on the tower bases. Very likely, there are
also mesh ground screens at the bottoms of the wells. The ground screens
probably extend up the sides of the wells and continue for a short distance
on the warehouse roof. The engineers who dreamed up this scheme were quite
ingenious. Constructing the warehouse without accidentally felling one or
more towers must have represented one heck of a challenge. And remember, the
towers were live with RF during much of the construction!

A historic rooftop AM DA belonged to the AM 550 in Cincinnati (WKRC now;
though it may have had different calls when the rooftop DA existed). It was
a two-tower array and the building was a hotel, which I believe still
stands. The rooftop towers may also still stand but they have not been used
as a DA for many decades. The towers may have begun life as the supports for
a long-wire antenna and may later have been converted to the vertical
radiators of the station's original DA. The rooftop antenna was
decommissioned many years ago when the station built a conventional
two-tower DA in a suburban location.

A true rooftop DA of much more recent vintage exists atop a warehouse
building in Oakland CA. The four-tower setup belongs to the 1510 station
licensed to Piedmont CA, which I believe is across SF Bay in Marin County.
The station's current calls are KSFN, but in a previous life were KPIG. At
one time, this array had five radiating elements (though only four towers).
The fifth element was a drop-wire suspended from a cable that joined the
tops of two of the towers.

There is a kind of bizarre connection between the Cincinnati station that
once had a rooftop DA and the Piedmont CA station that has a rooftop DA. The
Cincy station's calls were WKRC, which is very close to the fictional WKRP,
also in Cincinnati. WKRP's fictional crosstown competitor (at least in the
mind of WKRP's ND, Les Nesman) was WPIG. One of the former call signs of the
Piedmont CA station with the rooftop DA was KPIG.

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

----- Original Message ----- 
From: "Laurence Glavin" <lglavin@mail.com>
To: "Kevin Vahey" <kvahey@gmail.com>; "Boston Radio Group"
<boston-radio-interest@lists.BostonRadio.org>
Sent: Wednesday, September 26, 2012 2:26 PM
Subject: Re: Boston downtown radio towers (1956)


> >----- Original Message -----
>>From: Kevin Vahey
>>Sent: 09/26/12 03:41 AM
>>To: Boston Radio Group
>>Subject: Boston downtown radio towers (1956)
>
> >After seeing this picture I have a vague recall of these towers, but I
> >have >no clue who they transmitted. Anybody have a clue?
> > >https://sphotos-b.xx.fbcdn.net/hphotos-ash4/470934_4296181715469_1623633222_o.jpg
>
>
> In my experience (WLLH, Lawrence and some time back WLLH in Lowell, and
> WALE-AM 1400 in Fall River) and through
> photos on Scott's tower calendars, few if any AMs ran directional arrays
> atop office buildings. I lived in the
> Seattle area when I was in the USAF (the US never lost a war during my
> period of active-duty) and KXA-AM 770
> there also had a wire suspended between two towers just like the ones
> pictured in this post. It appears that
> KTLK-AM 1150 in Los Angeles has multiple towers for a directional array
> atop what looks like a warehouse
> building if I type the coordinates in Google or Bing maps and click on
> satellite or birdseye view.