ETS-Lindgren 3141 BiConiLog Log-Periodic/T Bow-Tie Antenna (Archived) - Manual (Page 4)

4
APPLICATION
Install the Model 3141 without the T bow-ties on an EMCO tripod or tower
adaptor. Insert the bow-ties one at a time and tighten the base knobs. Attach each T end
frame with four knobs. Connect an N-type coaxial cable from the antenna connector to a
generator or receiver. Contact with any metal or non-metallic structure can capacitively
load the antenna which may cause unrepeatable results. Therefore, care must be taken to
ensure that no part of the dipole elements or bow-ties are in contact with the tripod or
tower, particularly in vertically-polarized tests. Where possible, run the feed cable
straight at least 1 meter or more back from the Model 3141 before dropping vertically.
Both horizontal and vertical polarization is easily accomplished when the Model
3141 is mounted on a tower. Vertical polarization on a tripod requires special
consideration. Since immunity power requirements are many dB lower for vertical
polarization, the T end frames can be removed when mounting vertically on a standard
tripod. A special tripod is available from EMCO for vertical polarization with T bow-ties
intact. Please contact EMCO for the recommended mounting scheme.
For emissions measurements, electric field strength in dB[V/m] is obtained from
( ) ( ) ( ) ( )
E V AF dBV / m dBV dB1 / m dB
= + + α
,
where V is the receiver or spectrum analyzer voltage reading, AF is antenna factor (see
attached calibration data), and
α
is cable loss, if cable losses are non-negligible. For
immunity testing, the electric field strength generated at a distance d can be approximated
Archived 3/18/10