Armstrong Tower

{{short description|Radio tower in Alpine, New Jersey}}

Image:USA NJ ArmstrongTower.jpg]]

The Armstrong Tower, also known as Alpine Tower, is a distinctive {{nowrap|129.5 meter}} (425 foot) tall lattice tower featuring three large cross-arms, located atop the Alpine, New Jersey palisades overlooking the Hudson River a few kilometers north of New York City at 40°57'39.0" N and 73°55'21.0" W (40.9607 -73.9225). It is owned by Alpine Tower Company and managed by {{nowrap|CSC Management, LLC}},{{cite web |url=https://www.cscmgt.net/history.php|accessdate=2020-06-02 |title=Tower history |publisher=CSC Management}} both owned by Charles E. Sackermann, Jr.{{cite web |url=https://www.cscmgt.net/team.php |accessdate=2020-06-02 |title=Our Team |publisher=CSC Management}}

The tower is the permanent transmitter site for locally based experimental station WA2XMN and Fairleigh Dickinson University's educational FM station WFDU, in additional to numerous directional radio services (including as a cell site). It is clearly visible from across the Hudson River and is used as a Visual flight rules waypointFAA New York Sectional Aeronautical Chart Legend by aircraft flying within the New York City Special flight rules area.{{cite web |url=https://www.faasafety.gov/files/gslac/courses/content/79/776/kneeboard.pdf |title=New York Special Flight Rules Area |publisher=Federal Aviation Administration |accessdate=2017-04-10 }}

The tower was originally constructed by inventor Edwin Howard Armstrong in 1938 for developmental activities that led to modern {{nowrap|FM radio}}. The original transmissions (W2XMN) occurred at {{nowrap|42.8 MHz}}.[https://archive.org/details/Radio-Craft_1939_04/page/n13/mode/1up/ "At Long Last---Static-free Radio!"], Radio Craft, April 1939, pages 588, 618-619.{{cite web |url=https://www.fybush.com/sites/2005/site-050610.html |first=Scott |last=Fybush |title=The Birthplace of FM Broadcasting, Alpine, N.J. |work=Tower Site of the Week |date=2005-05-10 |accessdate=2020-06-02}} At the tower base is a building originally used for research by Armstrong, which still has the W2XMN call sign engraved above its main entrance. This building currently houses the Armstrong Field Laboratory, and serves as a museum containing artifacts from the development of FM radio technology.{{cite web |url=http://www.nparc.org/2006/Armstrong/armstrongtower.htm |title=Armstrong Tower Field Trip |publisher=New Providence Amateur Radio Club |year=2010 |accessdate=2011-08-22}}

The structure was also used as a temporary transmitter site for some of New York City's television stations after the collapse of the World Trade Center, including its transmitting antenna, following the September 11, 2001 attacks.[https://www.nytimes.com/2001/10/14/nyregion/a-nation-challenged-a-tower-in-alpine-keeps-new-york-tv-on-the-air-now.html "A Nation Challenged: A Tower in Alpine Keeps New York TV On the Air Now"] by Robert Strauss, New York Times, October 14, 2001.{{cite web |url=https://www.fybush.com/wtc-recovery/ |title=9/11 Plus One |work=NorthEast Radio Watch |first=Scott |last=Fybush |date=2002-09-10 |accessdate=2017-04-10}}