Radio Station Antennas

Anyone interested 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.


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.


740 CHWO Toronto, Canada

CHWO antenna tower is 650 feet tall.  It is located in Hornby (north of Mississauga), Ontario.  Two transmitters feed this antenna, CHWO 740 kilocycles and CJBC 860 kilocycles (french language programming).
CBL 740 kilocycles was on the air here before CHWO took over, and together with CJBC were the backbone Canadian Broadcasting System (CBC) stations of southern Ontario.

Close view of the tower base.

The original 50,000 watt Continental transmitter on 740 kilocycles, used by CHWO.


1010 CFRB Toronto, Canada

Directional array 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.

CFRB Transmitter, with output of 50,000 watts on 1010 kilocycles, is manufactured by Continental.


1050 CHUM Toronto, Canada

1050 CHUM was Canada's famous number one rock and roll top 40 radio station in the 1960's and 1970's.  The 6 tower directional array on 1050 kilocycles is located right on the shore of Lake Ontario in Clarkson (Mississauga), Ontario.  Using two or more towers and feeding them with appropriate amounts of the total radio energy and with delayed phase from the main tower allows the radiation pattern to have deep nulls or cancellations in specific directions while increasing the radiation in other directions.  The main reason for doing so is to prevent interference in the direction of other radio stations on the same frequency, especially at night when the radio waves can travel thousands of miles distance.

Close view of the CHUM towers by Lake Ontario.

The famous 1050 CHUM transmitter - a Continental model 317C-2 serial number 299 - from which came 50,000 watts of rock and roll during the 1960's and 1970's when music history was being made.  Everyone under age 35 it seemed listened to 1050 CHUM in Toronto back then!



700 WLW Cincinnati, Ohio

700 WLW Cincinnati Antenna of 700 WLW Cincinnati, Ohio is 831' high. 700 WLW Cincinnati 700 WLW Cincinnati The base of the WLW tower - a porcelain insulator supporting 200 TONS of steel!
Notice the lightning protection gap at the right, which passes lightning energy safely from the tower to ground instead of into the transmitter building.

The transmitter room.


1080 WTIC Hartford, Connecticut

1080 WTIC Hartford 1080 WTIC Hartford Another view of the two towers
1080 WTIC 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 Hartford WTIC 1080 Hartford
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 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 WNBC) and 880 WCBS, New York City, NY

Close view of antenna on High Island, NY.

WFAN transmitter, a Continental 50,000 watt unit

WCBS transmitter, a Harris 50,000 watt transistorized unit

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.

Before 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, NY.