The ETS-Lindgren Model 3148 Log Periodic Dipole Array is a linearly polarized, broadband antenna designed to operate over the frequency range of 200 MHz to 2 GHz. The choice of scaling factors, the various diameters of each element, and the center-to-center spacing of the booms are such that excellent VSWR characteristics are obtained throughout the operating frequency range (See Model 3148 VSWR data in the “Typical Data” section of this manual). The precise design of the feed and positioning of the elements on the boom yield optimum phase relationship. This causes the active region, at any given frequency, to propagate RF energy towards the smaller elements leaving the elements behind it electrically dead.
The Model 3148 antenna fully satisfies the CISPR-16 cross-polarization rejection requirement and has better than 20 dB cross-polarization rejection below 1000 MHz. The constant gain of the antenna yields an antenna factor that varies linearly with frequency as shown in the “Typical Data” section of this manual. The variation is smooth; therefore, accurate interpolation of performance between specified frequency points is simple.
The Model 3148 Log-Periodic antenna is constructed of lightweight, corrosion-resistant aluminum, providing years of trouble-free indoor and outdoor service.
The antenna is provided with an integral mount and the necessary attachments to mount the antenna to either a tripod (with a ¼-20 threaded mount) or an ETS-Lindgren antenna mast. Individual antenna calibration data is included with each antenna.