DALLAS — Nova Electronics has extensive experience in the design and construction of “elevated counterpoise” systems for AM radio stations. These systems have been shown to be operationally equal to a buried ground system, with drastic savings in labor and materials, and far less susceptible to damage and wear.
In an elevated counterpoise system the radials are not buried but are above ground. Here, for WDTW, the radials are attached at the base of the tower, then slope up 15 feet at about 20 feet out and continue until terminated by design or space limitations.
Elevated radials are an inexpensive and practical solution where there is sufficient property to install a minimum of six equally spaced radials a full quarter wave in length. They may be used to replace damaged buried systems or for new installations.
In new installations, these systems allow continued farm use of the land, installation in rocky areas where a buried system would not normally be employed and implementation of a station in environmentally-sensitive areas where the land disturbance associated with buried systems would be prohibited. Based on the experience base, concerns about stability in varying weather conditions or efficiency problems are unfounded when systems are designed and installed properly.
This design has been proven at many AM stations, including most recently at WDTW, and also WPCI, KXKW, WNJO, WGNY, WWJZ, WVNJ and KNGR. The only disadvantage is in directional antenna systems, as it is not currently accepted for MoM analysis, but that is expected to come. However, the large cost-saving over a traditional buried system will more than offset the additional cost of a traditional proof.
In probably one of the few reconstruction projects occurring in the Detroit area, WDTW recently was rebuilt from the ground up. WDTW started off just after World War II in 1946 as WKMH, and in 1963 became WKNR, “Keener 1310,” one of Detroit’s legendary rockers. At the end of 2012, then-owner Clear Channel announced they would be closing the station and donating it to the Minority Media and Telecommunications Council.
The station was dismantled and all towers demolished, with nothing but the transmitter building and tower bases remaining. In 2014 it was acquired by Pedro Zamora, and in March 2015 Nova Electronics was contracted to rebuild it.
The station was rebuilt under the existing license in order to save considerable time and money. Although the original array was an old Earl Cullum-designed distributed array, it was updated as much as possible to modern standards, while leaving the less-than-ideal original design parameters, due to the limited time remaining to return it to operation. So it was decided to make the best of what we had to work with, and find a way to make it perform to maximum potential.
Several changes were made, to improve performance and save considerable expense. The original towers were 105 degrees/210 feet tall, and the new Trylon towers were lowered to 195 feet through top-loading. Also, as the site was constantly wet, an elevated counterpoise was installed instead of a standard buried ground system.
At the lower height, no paint and lights were required, and the elevated counterpoise required only 7,000 feet of wire, as opposed to over 20 miles with the conventional system. It took only days instead of weeks to construct. Between the two, this resulted in a savings of almost $100,000. This eliminated the ability to perform a Method of Moments proof, but the extra expense of a standard proof was offset by the huge savings.
In running the Proof of Performance, we compared the new array with a proof from the last modification about 20 years ago. Measured performance was equal to slightly better, compared to the conventional buried ground system in use during the old proof. This stood as confirmation of the performance of an elevated counterpoise system. While saving a significant amount in materials and labor, no sacrifice in radiation efficiency was noted.
For information, contact Mike Vanhooser at Nova Electronics in Texas at (214) 725-5621 or visit www.novaelectronics.net.