Historic Treatise on the WSM Blaw-Knox Tower

[k4kyv]

This is the most detailed history and description of the WSM site I have seen to date. Includes photos and blue-prints of the tower and buildings on the site, and details of the history of the station following erection of the tower.

National Register of Historic Places Registration Form

[Ed/KB1HYS]

If it's a historic site, does that mean they won't be able to drop the antenna with out some sort of gov. approval?

[K5UJ]

Other links of interest:

John Hettish of Middle TN Two-Way had, at one time, over 100 photos on line of the WSM tower taken during a job they had on it.  There were closeups of the tower structure from top to bottom, guy anchors, cables from an angle looking down along them to the ground, the view from the top, ... everything.  Now for some reason, they're gone except for two or three.   

http://hawkins.pair.com/wsm.html

http://hawkins.pair.com/wsm/

http://hawkins.pair.com/blaw-knox.html

http://www.fybush.com/site-020424.html

http://www.oldradio.com/archives/stations/ccs/wsmtwr.htm

http://www.oldradio.com/archives/stations/ccs/wsmpix.htm

[W4AAB]

John's business partner passed away a few years ago, and John was left trying to keep up operations in two different cities. I haven't talked to him in some time.He was active on a 440 mHz repeater system around Nashville.I will check on him next week.

[Ed/KB1HYS]

WGIR in Manchester NH has a BK antenna.  I love to drive by it on the highway.  Admittedly I often wish I could run my rig through something that impressive.  I think the appearance alone is worth 3dB

[k4kyv]

...Prior to using the Blaw-Knox tower, WSM used a "cage" type antenna that was supported by two self-supporting towers. A wire was strung between the towers and a vertical feed wire fed the center from a tuning house directly centered between the towers. This was also referred to as a "flat top" antenna. Dr. George Brown et. al, of RCA fame, impressed the FRC with a vertical, series fed antenna that used 120 equally spaced quarter wavelength radials as 360 degree counter-poise. There have been no improvements on this basic design to date.

There has been some suggestion that the Blaw-Knox dual cantilever tower was designed to be "fat" in the middle to accommodate a current maximum in a 1/2 to 5/8-wave length tower. This was purely consequential and was not a consideration in the design of the tower. In one writing, Dr. Brown scoffed at “the arrogance of Blaw-Knox” in designing such a structure, insinuating it was for a visual image only.

Another frequently asked question is “why didn’t they use a 90 degree tower?” The answer is: Part 73.182(6)(0) of the FCC rules require a minimum field of 362 millivolts/meter/km at 1 kilowatt for class “A” AM stations. This field can only be developed by a radiator in height of 164.4 electrical degrees or higher and 120 ground radials with an average length of 90 electrical degrees.

W. Watt Hairston (K4WRF)
Chief Engineer, transmitters.
WSM, WSM-FM and WWTN
Nashville, TN.

http://www.oldradio.com/archives/stations/ccs/wsmtwr.htm