Radio Station Antennas
in radio is interested in radio antennas. The first antennas in the
early 1900's were necessarily large structures, because the radio frequencies
originally used were low, and therefore the radio waves had a long wavelength.
In order for the antenna to radiate electromagnetic waves efficiently and
present a high enough electrical resistance for connection to a practical
radio transmitter at such frequencies, it had to be physically large.
The imposing towers and array of wires were impressive to say the least.
Today, there is a remnant of these original antennas in existence!
These are the AM radio station antennas, because the AM broadcast band
still uses low radio frequencies, namely 540 - 1600 kilocycles per second.
How long this band will be used into the 21st century is not known, although
there are still many hundreds of millions of legacy AM radio receivers
in homes and cars. In emergencies, the simple AM radio has proven
to be a lifesaver and the only reliable communications to the public in
this digital computer age when everything else is shut down or damaged
(satellites, FM radio, TV towers on buildings) or overloaded (internet,
cell phones). This plus the fact that low frequencies can travel
thousands of miles away at night, is the main reason AM radio is still
here. But however you look at it, now is the time to photograph these
antennas and to enjoy them.
Types of radio antennas
There are two basic
types of radio antennas that can be used. All antennas are variations
or modifications of these two types. They are the Marconi and Hertz.
The Marconi antenna is a wire or tower at the earth's surface, mainly
vertical, although the upper parts of it may be bent horizontally.
The ground is an integral part of the antenna, and aids in its radiation.
The Hertz antenna is a wire, either horizontal or vertical. The Hertz
antenna does not rely on the ground for its operation, and in fact, usually
performs best when installed far above the earth's surface. A Hertz
antenna must be twice the size of a Marconi antenna, everything else being
equal. Thus at low frequencies where any antenna will be very large
to begin with, the Marconi antenna is the only practical antenna since
it is the smallest size possible, and also at the same time benefits from
physical stability by having the ground available for a support.
The real feature of a vertical Marconi antenna is its nondirectional radiation
property - it radiates radio waves equally well in all directions, since
it is symmetrical in all horizontal angles, making it ideal for broadcasting
over a wide circular area surrounding the antenna.
Pictures of antennas
This is a typical Marconi
antenna from the mid 1910's era. The parallel horizontal wires on
the spreaders are merely loading devices to bring the resonant frequency
of the antenna down to the low frequencies generated by the transmitter.
The heights of the masts are 50' and 60', 100' apart. Ironically,
the main radiating part of this antenna is the somewhat vertical lead wire
(can't be seen in the photograph) between the far end of the antenna and
the attic window. Obviously this antenna will not be nondirectional,
however, it does radiate low frequency radio waves efficiently. This
is the home antenna of amateur radio operator Hiram Percy Maxim in Hartford
Connecticut, 1915. This same type of antenna was used on the ship
Titanic, and by the first radio broadcasting stations.
When steel structures
were developed, commercial radio broadcast stations used vertical tower
antennas which could then be the full electrical length without horizontal
bends, for true nondirectional radiation.
TORONTO, CANADA RADIO ANTENNAS
590 CJCL (formerly 1430 CKFH) Toronto, Canada
1430 CHKT (formerly 590 CKEY) Toronto, Canada
1540 CHIN Toronto, Canada
These are the Toronto
Islands, with Center Island in the foreground, and the city of Toronto
on the mainland looking north. The beach in the foreground is called
Gibraltar Point. Currently you can see an array of 6 towers near
the north end of Center Island, and to the south of this, on the
water treatment plant green square, an array of 5 towers. The somewhat
confusing history of radio transmission from this Island follows.
There used to be an
antenna array of 5 towers, each 150 feet high, built right in the water
about 1600 feet south off Gibraltar Point. This was the antenna system
of the famous 590 CKEY in the 1960's and 1970's transmitting 10,000 watts
- Toronto's number 2 station (1050 CHUM was number 1).
The 6 tower array of
150 feet height visible on the north side of the Island was the home of
1430 CKFH, 50,000 watts, which in 1981 became 1430 CJCL.
Then came big changes...
In 1985 590 CKEY moved
to a 9 tower array in Grimsby, Ontario with 50,000 watts power, and the
5 tower antenna in the water was demolished. 590 CKEY became 590
CKYC in 1991. In 1995 CKYC, which was a commercial failure, was sold
off, and the new owners decided to sell 590 CKYC to 1430 CJCL which allowed
the programming of the two stations to be swapped. Thus CJCL went
to the more valuable frequency 590 kilocycles using the 9 tower array in
Grimsby, Ontario, and CKYC went to 1430 kilocycles (the 6 tower array still
on the Island). So CKEY indirectly started and ended its life on
the Toronto Islands - from the old 5 tower array in the water to the present
6 tower array! Finally in 1997 CKYC was sold and became the current
1430 CHKT, with Chinese programming. What a change from being the
number 2 rock and roll station in Toronto!
Satellite view of
the 6 tower array on Center Island, now used by 1430 CHKT Toronto.
In 1985, CHIN 1540 moved
to the Toronto Island and built a new 5 tower antenna array on the Gibraltar
Point water treatement plant grounds as seen in this satellite view (same
as the green square seen in the first photograph in this section), directly
south of the 6 tower array then being used by 1430 CJCL. 1540 CHIN
transmits 15,000 watts of power.
640 CFMJ (formerly CFGM 1320) Toronto, Canada
The 8 tower directional
array, 361 feet, of 640 CFMJ Toronto. The towers are just south of
Lake Ontario in Lincoln, and beam the signal north across the lake to Toronto.
The original station was 1310 CFGM and then 1320 CFGM in 1976, from an
antenna site in Mississauga, Ontario. In 1988 the station moved to
the current site and became 640 CFGM. In 1990 it changed to 640 CHOG.
In 1999 it changed to 640 CFYI. Finally it became the current 640
CFMJ in 2002.
680 CFTR (formerly 680 CHFI) Toronto, Canada
The 8 tower directional
array, 410 feet, of 680 CFTR Toronto. The towers are just south of
Lake Ontario in Grimsby, and beam the signal north across the lake to Toronto.
The Rogers Broadcasting owned 680 CHFI became 680 CFTR in 1971, the "TR"
representing Ted Rogers. The station moved to this site in 1985 from
Mississauga, Ontario with full time day and night power of 50,000 watts.
1010 CFRB Toronto, Canada
of 4 antenna towers, each 550 feet tall, in Clarkson (Mississauga), Ontario,
near the lake shore. They are just northwest of the 1050 CHUM towers.
with output of 50,000 watts on 1010 kilocycles, is manufactured by Continental.
UNITED STATES RADIO ANTENNAS
Close pictures of 1080
WTIC Hartford, showing the antenna tuning coils in line between the transmitter
and the towers, and the base of the giant east tower. Obviously,
being daytime, the east tower is OFF, allowing the engineer to safely touch
the antenna! This is real radio!
1080 WTIC Hartford, Connecticut
Another view of the two towers
Hartford, Connecticut, uses only the left (west) tower during the day.
At night both towers are used and provide a null in a direction to protect
a distant station on the same frequency, namely 1080 KRLD Dallas, Texas.
1080 WTIC 50,000 watt Continental transmitter.
770 WABC New York City, NY
770 WABC New York City. Antenna tower is actually in Lodi, NJ, and
is 648' high.
770 WABC General Electric transmitter - 50,000 watts.
660 WFAN (formerly 660
WNBC) and 880 WCBS, New York City, have shared this single 528' antenna
since 1963. It is on High Island, NY. The two transmitters
feed the single main antenna through a filtered power combiner.
1963, 660 WNBC was located in Port Washington, NY, and 880 WCBS was located
on Columbia Island, NY. Before 1946, 660 WNBC was the famous 660
WEAF, the flagship station of the NBC radio network of the 1930's and 1940's,
and was located in Bellmore, L.I., NY from the 1920's until 1940.
Old 660 WEAF antenna in Bellmore, L.I., NY.
Original WEAF transmitter in 1929 - 50,000 watts.
Later WEAF RCA transmitter in Bellmore, L.I., NY, 1932 - 50,000 watts.
660 WEAF in Port Washington, NY, with two 322' towers directional antenna,
1940. Note the "swimming pool" in front - a cooling pond for the
circulating water pumped to cool the transmitter tubes inside!
Overall view of 660 WEAF in Port Washington, NY, 1940.
660 WEAF RCA transmitter in Port Washington, NY, 1940 - 50,000 watts.
Old 880 WCBS antenna on Columbia Island, NY.
Old 880 WCBS transmitter built by Federal Telephone, on Columbia Island,