ETS-Lindgren 3142B BiConiLog Antenna (Archived) - Manual (Page 11)

MODEL 3142B BICONILOG™ ANTENNA Application Without the Optional End Plates
APPLICATION WITHOUT THE
OPTIONAL END PLATES
For emissions measurements, electric fields strength in
dB[V/m] is obtained from
E(dB[V/m]) = V(dB[V]+AF(dB[1/m])+
α
(dB)
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 electrical field strength generated
at a distance d can be approximated by
E(V/m) =
√
(30 P g) / d
where d is in meters, g is the numeric gain (10 G[dB]/10 , see
attached calibration data), and P is antenna net input power
in watts. An estimate of the power required for any field
strength E can be obtained from Figure 4 in the Typical
Data section below, which shows power required in watts
to generate 1 V/m. Power shown is calculated from the
measured gain and corrected for VSWR. For any other field
strength, multiply the power in watts by desired E-field
squared, or
P(E V/m) = E 2 P(1 V/m)
Actual transmitted field strength should be verified using
an ETS-Lindgren electric field probe or equivalent. An
estimate of the power required taking VSWR into account
is obtained from
P
f
= P
n
/ {1-[(VSWR-1)/(VSWR+1)] 2 }
where P
f
is the forward (amplifier output) power and P
n
is
the new power as discussed above.
© EMC TEST SYSTEMS, L.P. – MARCH 2002
7
REV C – PN 399229
Archived 09/23/10