ETS-Lindgren 3160 Pyramidal Standard Gain Antenna - Manual (Page 10)

10 Introduction www.ets-lindgren.com
Each Model 3160 Series antenna comes completely assembled with a
high performance, low VSWR, coax-to-waveguide adapter. Below 18 GHz, the
transition from coax to waveguide is made using a female Precision N connector.
Above 18 GHz, the transition uses female K connectors. The coax-to-waveguide
adapters are the only power-limiting component, and can be removed if
high fields are desired. For this purpose, the RF generator must be equipped with
waveguide ports. In such a configuration, fields in excess of 10,000 V/m at
10 meters can be obtained.
Each Model 3160 Series antenna comes with a standard 1/4–20 mount.
Horizontal and vertical polarizations are obtained by rotating the antennas from
one position on the mount to the other. The mounts have been placed so as not
to interfere with incoming electromagnetic energy. For the variety of mounting
options available for the Model 3160 Series, see Mounting Instructions on
page 20.
The Model 3160 Series may be used for either transmission or reception. The
50 ohm input impedance is well-matched for generating high electric fields with
little power reflected back to the amplifier, reducing the chance of saturation. As
a receiver, the antennas are matched to free space (377 ohms). Typical
performance data is provided beginning on page 37. Methods for radiated
emissions measurement are described on page 43.
For TEMPEST applications, all Model 3160 Series antennas, especially models
3160-03 and up, can be mounted on standard 12-, 18-, or 24-inch reflector
dishes. The resulting antenna factor is usually about 20 dB lower than that of the
antennas by themselves. However, the HPBW drops to less than 50 and the
far field distance increases drastically making near field performance less
predictable.