Blaw-Knox Tower
Encyclopedia
Pittsburgh, Pennsylvania
Pittsburgh is the second-largest city in the US Commonwealth of Pennsylvania and the county seat of Allegheny County. Regionally, it anchors the largest urban area of Appalachia and the Ohio River Valley, and nationally, it is the 22nd-largest urban area in the United States...
. The company is today best known for its radio towers
Mast radiator
A mast radiator is a radio mast or tower in which the whole structure itself functions as an antenna. This design is commonly used for transmitting antennas operating at low frequencies, in the VLF, LF and MF ranges, in particular those used for AM broadcasting. The metal mast is electrically...
, most of which were constructed during the 1930s in the United States
United States
The United States of America is a federal constitutional republic comprising fifty states and a federal district...
. Although Blaw-Knox built many kinds of towers, the term Blaw-Knox tower (or radiator) usually refers to the company's unusual "diamond cantilever" design, which is held upright by guy wires attached only at the vertical center of the mast, where its cross-section is widest. A 1942 advertisement claims that 70% of all radio towers in the U.S. were built by Blaw-Knox.
Extant examples
Many Blaw-Knox towers, of both conventional (uniform cross-section) and diamond design, remain in use in the United StatesUnited States
The United States of America is a federal constitutional republic comprising fifty states and a federal district...
. Few of the diamond towers were built, and several remain; all transmit AM radio signals:
- WSMWSM (AM)WSM is the callsign of a 50,000 watt AM radio station located in Nashville, Tennessee. Operating at 650 kHz, its clear channel signal can reach much of North America and various countries, especially late at night...
, Nashville, TennesseeNashville, TennesseeNashville is the capital of the U.S. state of Tennessee and the county seat of Davidson County. It is located on the Cumberland River in Davidson County, in the north-central part of the state. The city is a center for the health care, publishing, banking and transportation industries, and is home...
: 808 ft (246 m); originally 874 ft (267 m); tower located in Brentwood, TennesseeBrentwood, Tennessee-Demographics:As of the census of 2000, there were 23,445 people, 7,693 households, and 6,808 families residing in the city. The population density was . There were 7,889 housing units at an average density of . The racial makeup of the city was 94.63% European American, 1.89% African American,...
. - WLWWLWWLW is a clear channel talk radio station located in Cincinnati, Ohio, run by Clear Channel Communications. The station broadcasts locally on 700 kHz AM...
, Cincinnati, OhioCincinnati, OhioCincinnati is a city in the U.S. state of Ohio. Cincinnati is the county seat of Hamilton County. Settled in 1788, the city is located to north of the Ohio River at the Ohio-Kentucky border, near Indiana. The population within city limits is 296,943 according to the 2010 census, making it Ohio's...
: 747 ft (227 m); originally 831 ft (253 m); tower located in Mason, OhioMason, OhioMason is an affluent city in southwestern Warren County, Ohio, United States, 22 miles away from Cincinnati . As of the 2010 census, Mason's population was 30,712. Mason has experienced fast growth, with its historic Main Street remaining at the center of the community...
. - WBTWBT (AM)WBT is a radio station in Charlotte, North Carolina, broadcasting on the AM dial at 1110 kHz. A 50,000-watt clear-channel station, it can be heard across most of the eastern half of North America at night. It simulcasts on WBT-FM, at 99.3 MHz in Chester, South Carolina. It is owned by Greater...
, Charlotte, North CarolinaCharlotte, North CarolinaCharlotte is the largest city in the U.S. state of North Carolina and the seat of Mecklenburg County. In 2010, Charlotte's population according to the US Census Bureau was 731,424, making it the 17th largest city in the United States based on population. The Charlotte metropolitan area had a 2009...
: three towers, 428 ft (130 m) each (one original, two reproductions from the original plans after the originals were destroyed by Hurricane HugoHurricane HugoHurricane Hugo was a classical, destructive and rare Cape Verde-type hurricane which struck the Caribbean islands of Guadeloupe, Montserrat, St. Croix, Puerto Rico and the USA mainland in South Carolina as a Category 4 hurricane during September of the 1989 Atlantic hurricane season...
) - WFEAWFEA-History:WFEA has been broadcasting continuously since 9:00 a.m. on March 1, 1932, making it New Hampshire's oldest radio station. It has always had the same call letters. During its long life, WFEA has had 10 owners. Saga Communications of New England LLC has operated WFEA since April, 1991. Saga...
, Manchester, New HampshireManchester, New HampshireManchester is the largest city in the U.S. state of New Hampshire, the tenth largest city in New England, and the largest city in northern New England, an area comprising the states of Maine, New Hampshire, and Vermont. It is in Hillsborough County along the banks of the Merrimack River, which...
: 400 ft (121 m) - WBNSWBNS (AM)WBNS — branded 1460 ESPN — is a radio station that broadcasts from Columbus, Ohio. The station, which originally went on the air as WCAH in 1922, currently broadcasts a sports talk format and carries ESPN talk programming. WBNS is also the flagship of the Ohio State Buckeyes radio network. It is...
, Columbus, OhioColumbus, OhioColumbus is the capital of and the largest city in the U.S. state of Ohio. The broader metropolitan area encompasses several counties and is the third largest in Ohio behind those of Cleveland and Cincinnati. Columbus is the third largest city in the American Midwest, and the fifteenth largest city...
: 380 ft (116 m)
Several additional diamond-cantilever towers were built at stations in the Central Valley of California
California
California is a state located on the West Coast of the United States. It is by far the most populous U.S. state, and the third-largest by land area...
but are less well-known. These towers were much smaller in both height and cross-section than the towers listed elsewhere; only one — KSTN, Stockton
Stockton, California
Stockton, California, the seat of San Joaquin County, is the fourth-largest city in the Central Valley of the U.S. state of California. With a population of 291,707 at the 2010 census, Stockton ranks as this state's 13th largest city...
— remains in use for broadcasting.
The following Blaw-Knox diamond-cantilever towers remain standing in Europe:
- Lisnagarvey MastLisnagarvey transmitting stationThe Lisnagarvey transmitting station is a facility for mediumwave broadcasting located in the townland of Magherageery, on the southern edge of Lisburn, Northern Ireland...
(constructed: 1936) at Lisnagarvey, Northern Ireland - Lakihegy TowerLakihegy TowerThe Lakihegy Tower is a 314 metre high radio mast at Szigetszentmiklós-Lakihegy. The Blaw-Knox type tower was built in 1933 and was one of Europe's tallest structures at the time of construction...
(constructed: 1933, height: 314 metres) at SzigetszentmiklósSzigetszentmiklósSzigetszentmiklósis a city in Pest county in Hungary with approximately 26,662 inhabitants.- Name :* Sziget – island: Szigetszentmiklós is a town in the Csepel Island* Szent Miklós – Saint Nicholas, who is the patron saint of Szigetszentmiklós...
-Lakihegy, HungaryHungaryHungary , officially the Republic of Hungary , is a landlocked country in Central Europe. It is situated in the Carpathian Basin and is bordered by Slovakia to the north, Ukraine and Romania to the east, Serbia and Croatia to the south, Slovenia to the southwest and Austria to the west. The...
(The tallest Blaw-Knox tower ever built) - Vakarel TransmitterVakarel TransmitterThe Vakarel Transmitter is a large broadcasting facility for long- and medium wave near Vakarel, Bulgaria. The Vakarel Transmitter was inaugurated in 1937. It has one directional antenna consisting of three guyed masts and another consisting of two masts....
(constructed: 1937, height: 215 metres) at Vakarel, Bulgaria - Stara Zagora TransmitterStara Zagora TransmitterThe Stara Zagora Transmitter is a high power mediumwave broadcasting station near Stara Zagora in Bulgaria. It has at least 3 guyed masts. One of these masts is a Blaw-Knox Tower. It is one of the few Blaw-Knox towers in Europe, along with similar masts at Vakarel, Bulgaria, at Riga, Latvia,...
at Stara ZagoraStara ZagoraStara Zagora is the sixth largest city in Bulgaria, and a nationally important economic center. Located in Southern Bulgaria, it is the administrative capital of the homonymous Stara Zagora Province...
, Bulgaria
Gallery
File:Radio-transmitter-antena-at-Vakarel.jpg|Vakarel radio transmitter