Installation Instructions Damper Kit for Grid Antennas

Bulletin 237077A

Description These damper strips (see Figure 1) may be installed from either the front or the rear of the antenna. Slots in the strip allow sliding it onto the antenna grid elements. The strips are installed perpendicular to the antenna grid elements regardless of the antenna's orientation corresponding to polarization. The kit is for use on all GP4 (4 ft, 1.2 m), GP6 (6 ft, 1.8 m), GP8 (8 ft, 2.8 m), and GP10 (10 ft, 3 m) Series antennas. Installation on GP4 Series Antenna (Figure 2) 1. Lubricate the slots of the strips using kerosene (parafin oil) or diesel fuel to ease installation. One row of three grid damper strips is required for each half of the antenna. 2. Twist open the end slot of the first damper strip and slide it onto the third element of the antenna. Make sure that this end of the strip is positioned 3 in (76 mm) from the antenna rim as shown. If you are working on a GP4-890 antenna, start installation at the second element instead of the third. Continue opening the slots and sliding the strip onto adjacent elements. 3. Install a second stip adjacent to the first so that they overlap across three antenna elements as shown. Install a third damper strip adjacent to the second and in line with the first as shown. The second and third strips must overlap across four antenna elements. Adjust the strips so that they are aligned and the center strip is equidistant between the spacer bar and the antenna rim. 4. Repeat Steps 1 through 3 for the opposite half of the antenna to complete the installation.

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