[TowerTalk] The history of using multiple towers for directional purposes

[Jim Brown]

This is a very interesting piece. The best job I ever had as a student 
was working in Pete Johnson's consulting office. It was in 1961. Pete, 
along with the late Carl Smith, had written the FCC technical Rules for 
AM broadcasting after WWII, which included the standards for protecting 
other stations from interference, how to document proposed antenna 
designs in a license application, and how to make the field measurements 
of a completed system to prove that they met their design goals.

Pete's practice consisted of the design of very sophisticated 
multi-tower arrays, in which array geometry, as well as the amplitude 
and phase of the current fed to each tower, was adjusted to produce the 
required protections. And this for a broadcast band that had been full 
for 20 years!

Our EE senior class got to tour both the WLW transmitter site and the 
adjacent Voice of America site in Mason, OH. Until it was torn down 
decades ago, the massive VOA antenna farm (two Sterba Curtains and 
something like 21 Rhombics) was visible from I-75, roughly midway 
between Dayton and Cincinnati. During our visit to WLW, they fired up 
the 500kW rig into a dummy load, which was cooled by a water bath out 
front of the building.

73, Jim K9YC

On 10/27/2023 5:49 PM, Radio KH6O wrote:
> Not sure if I sent this earlier:
> 
> https://www.radioworld.com/columns-and-views/roots-of-radio/the-development-of-the-directional-am-broadcast-antenna?utm_term=5E35C2B9-3044-4235-9961-04D879406E09&utm_medium=email&utm_content=5816E138-5287-4D1C-BBFA-9CA84B94BB6D&utm_source=SmartBrief