The Model ATH4G8 is a wide band, high gain, microwave horn antenna that provides a minimum gain of 11.5dB over isotropic. The Model ATH4G8 supplies the constant high intensity fields necessary for RFI/EMI field testing within and beyond the confines of a shielded room. A removable gain enhancer is included to insure the required field strength when conducting 3 meter testing.
These VHF antennas solve the problem of phase center movement, a common difficulty with log periodics. The phase center, or active region of a log periodic moves from the tip of the boom to the back as frequency decreases. Such movement makes high level fields tough to achieve, especially at the low-frequency end. But with the AT1225 or 1250 and a 10 kW input, field strength is more than 100 V/m at 8 meters.