A PATTERN STUDY measures the effect a tower has on the antenna signal. PATTERN OPTIMIZATION is a modification of the pattern to make it more circular or directional.

In a Pattern Study, the antenna is mounted on a replica of your tower and measurements are made to determine the relative signal strength around the tower. The measurements are repeated for different mountings and orientations of the antenna and the data is used to select an antenna mounting which meets your requirements.

Optimization requires the addition of parasitic radiating elements to be mounted near the antenna to direct pattern in a more desired direction.

Dielectric's FM azimuth pattern measurements are performed in the specially designed anechoic chamber operating at 4.4 times FM carrier frequencies. At this frequency, the antenna, tower structure, and transmission lines can be accurately modeled to 1/4.4 scale. The anechoic chamber allows for a more detailed study, in a noise and reflection free environment, resulting in the most accurate results.

Test Method

The antenna/structure rotates 360 degrees while receiving a signal from a source antenna. The source is fed by an HP signal generator with directional coupler located at the antenna input. A reference signal is obtained from this coupler and compared to the "receive" signal of the antenna under test.

An optical encoder, located at the antenna under test, sends signals to a computer where custom software converts antenna orientation and signal information with each antenna rotation. Measurements are performed under several mounting configurations to obtain the best possible patterns.

Pattern Optimization

Pre-Optimization

Post Optimization