ELECTRO-METRICS ALP-70
(ALP70-1)
DESCRIPTION AND USE ELECTRO-METRICS
ALP-70 LOOP ANTENNA
1.0 Description
The ALP-70 Loop Antenna is designed to obtain magnetic field measurements from 10
kHz to 30 MHz. The antenna is suited for use in compliance testing to MIL-STD-461A/B/C,
CISPR standards, plus other government and federal standards.
The antenna can be used with any 50
instrument being designed and calibrated for use
in a 50
system. The antenna incorporates a balanced faraday shield that reduces its response to
electric fields to a vanishingly small amount allowing it to obtain practically pure magnetic field
measurements.
The antenna is designed to work into a 50
system and the calibration chart is based on
this use. The calibration chart gives values of antenna factor for finding magnetic field strength
H.
To find the field strength H in dB(µA/m), add the factor in dB(S/m) to the measured two-
terminal input voltage on the 50
analyzer/receiver in dB(µV).
To find the flux density B in dB(pT), add 2 dB to the field strength H reading.
The ALP-70 Loop Antenna is, electrically, a magnetic dipole and thus having a dipole
pattern must be oriented for best sensitivity.
The base plate has a 5/8-11 threaded receptacle for mounting to the Model TRI-136
Tripod. This allows the loop antenna to be mounted either vertically or horizontally with respect
to a horizontal plane.
