Most Popular Articles
WAOK-AM Uses Method of Moments Proof
The antenna system employs Kintronic Labs VSU-1 voltage sampling units.
WAOK MoM Proof Methodology
Following the installation of the voltage sampling system in the WAOK array Don Crain visited the site to conduct phase 1 of the MOM proof process. All the WAOK towers are 179.3° electrical height. Towers 1 and 2 are fixed cross-section guyed towers each having a facewidth of 30.25". Towers 3 and 4 are tapered cross-section triangular self-supported towers having a base cross section of 24.75' tapering to a cross section of 30.25" at the 290' level and having a fixed cross section of 30.25" for the top 65'. Robert LaFore, the CBS Atlanta market chief engineer, had to arrange for a tower rigger to climb one of the self-supported towers and measure the facewidth as a function of height due to the lack of any tower drawings at the station. This information was critical for the tower modeling effort required for the MOM proof.
Upon arrival at the station Crain measured the impedance of each tower with the other towers either open or shorted. Figure 2 shows the tower base installation configuration for the voltage sampling units.
A four-port network analyzer with an RF power amplifier and a Tunwall Radio directional coupler based on the technique developed by Ron Rackley was used to make the measurements as shown in Figure 3.
The impedance measurements were made at the tower side of the open J-plug in each VSU unit as shown in Figure 2 with the ATU output J-plug open as well. The impedances measured for the shorted case are shown in Table 1.
|Tower 1||147.73 - j300.07|
|Tower 2||110.91 - j278.32|
|Tower 3||46.104 - j111.34|
|Tower 4||44.293 - j104.32|
|Table 1. Measured tower impedances|
- continued on page 3
Acceptable Use Policy blog comments powered by Disqus
[an error occurred while processing this directive]
Today in Radio History
The history of radio broadcasting extends beyond the work of a few famous inventors.
Read each issue online in our Digital Edition Format in your Web browser.
EAS Information More on EAS
The feed provides feeds for all US states and territories.
Need a calendar for your computer desktop? Use one of ours.
Information from manufacturers and associations about industry news, products, technology and business announcements.
Browse Back Issues[an error occurred while processing this directive]
Also in the November Issue
- Trends in Technology: HD Radio Transmission Update
- Franken FM Stations
- Wi-Fi on Wheels: The Connected Car
- Field Report: Yamaha MG10XU
- Transmitter Site Cleanup