LTAR 7/22: WSUN

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

In 1931, when WSUN St Petersburg became the first directional station in the
US, it and WFLA Tampa shared time on 620. Because much of the path from
Tampa Bay to Milwaukee is over salt water, the station interfered with WTMJ
at night and the FCC had threatened to change the hours of operation to
daytime. The DA was constructed to prevent that draconian measure.

The array consisted of two vertical radiators. Contrary to what Garrett
suggested, there was no element that consisted of the former vertical feed
wire of a long-wire antenna. But there were several antennas that used
exactly that device to effect a conversion from a long-wire to a DA.

The most famous such conversion was probably that of WOR in Carteret NJ.
It's unknown whether the designers of WOR's long-wire were extremely lucky
or whether they were prescient and foresaw the evolution of the DA and thus
positioned the support towers of the long wire in such a way that they could
later be combined with the feed wire to form a three-element DA. What _is_
known is that when the long wire was converted to a DA, the DA was a perfect
match for the requirements of WOR. Carteret is just west of Staten island,
and the figure-eight pattern sent signal maxima over New York City and
toward Hartford as well as toward Philadelphia, where WOR became the
strongest out-of-market signal and often appeared in the Philadelphia
ratings. In addition, nulls were positioned over the Atlantic and toward
legacy co-channel station CKVM, Ville Marie PQ. WOR's converted long-wire
was so effective that it wasn't until the early 1960s that the station got
around to replacing it with the more modern asymmetrical three-tower array
in Lyndhust NJ. That was almost a quarter century after the other New York
stations had replaced their long wires with base-insulated towers.

There is still one converted long wire in use in the US (or if it's no
longer in use, it was just recently taken out of service). That's at the AM
1260 north of Los Angeles. The COL used to be San Fernando; it might be
Beverley Hills now.

WSUN/WFLA's pioneering DA was soon followed by another DA in the Tampa Bay
area (the second DA in the US). This one was at WDAE Tampa, then probably on
1210 or 1220. Whereas the WSUN/WFLA DA had used a transmission line as a
phasor and was thus extrmently difficult to tune, WDAE's lumped-element
phasor was more compact and much simpler to tune. The technology in WDAE's
phasor is employed in all modern AM DAs.

--
Dan Strassberg, dan.strassberg@att.net
617-558-4205, eFax 707-215-6367