
E-FIELD PROBE 
EF1891 
Measuring electric fields  
from 3 MHz to 18 GHz 
using instruments in the NBM-500 family 
 General public and occupational field 
exposure from radio broadcasting, telecoms, 
and radar 
 Isotropic (non-directional) measurement  
 64 dB dynamic range without changing 
measurement range 
The probe contains three orthogonally arranged dipoles with detector 
diodes. The three voltages, corresponding to the spatial components, 
are available individually at the probe output. The NBM basic unit 
calculates the resulting isotropic field strength. 
APPLICATIONS 
The probe detects electric fields from 3 MHz to 18 GHz, covering the 
fields generated by broadcasting, telecoms, and radar. The dynamic 
range from 0.6 V/m up to 1,000 V/m (64 dB) makes the probe ideal for 
measuring exposure in both the general public and the occupational 
environment. 
PROPERTIES 
The probe is designed with mechanical and electrical properties ideal for 
field use. The probe head is made of foam material to provide effective 
protection for the sensors, while having excellent RF characteristics. 
The electric destruction limit of 1,600 V/m for continuous wave signals is 
several times higher than any of the human safety limit values. 
CALIBRATION 
The probe is calibrated at several frequencies. The correction values are 
stored in an EPROM in the probe and are automatically taken into 
account by the NBM instrument. Calibrated accuracy is thus obtained 
regardless of the combination of probe and instrument. 
NSTS 0312-E0234C-0.0  1 / 2  Subject to change 
 

SPECIFICATIONS a 
Probe EF1891  Electric (E-)Field 
Frequency range 
Type of frequency response  Flat 
Measurement range 
Dynamic range  64 dB  
CW damage level  1600 V/m  700 mW/cm² 
Peak damage level 
Sensor type  Diode based system 
Directivity  Isotropic (Tri-axial) 
Readout mode / spatial assessment  3 separate axes 
UNCERTAINTY 
Flatness of frequency response
Calibration uncertainty not included 
Calibration uncertainty 
@ 0.2 mW/cm² (27.5 V/m) 
Linearity 
Referred to 0.2 mW/cm² (27.5 V/m) 
Isotropic response 
Temperature response  +0.2/ -1.5 dB (±0.025 dB/K @ 10 to 50 °C ) 
GENERAL SPECIFICATIONS 
Calibration frequencies 
Recommended calibration interval  24 months 
Temperature range 
  Operating 
  Non-operating (transport) 
Humidity  5 to 95 % RH @ ≤28 °C  ≤26 g/m³ absolute humidity 
Size  318 mm x 66 mm Ø 
Weight  90 g 
Compatibility NBM-500 series meters 
Country of origin  Germany 
(a) Unless otherwise noted specifications apply at reference condition: device in far-field of source, ambient temperature 23±3 °C, relative air humidity 25% to 75%, sinusoidal signal 
(b) Cutoff frequency at approx. -3 dB 
(c)
Pulse length 1µsec, duty cycle 1:100 
(d) Frequency response can be compensated for by the use of correction factors stored in the probe memory 
Accuracy of the fields generated to calibrate the probes 
(e) 
(f)
Uncertainty due to varying polarization (verified by type approval test for meter with probe). Ellipse ratio included and calibrated for each probe 
(b) 
(c)
  16 kV/m  70 W/cm² 
 (d) 
3 MHz to 18 GHz 
0.6 to 1000 V/m (CW) 
0.6 to 35 V/m (True RMS) 
±1 dB (10 MHz to 1.8 GHz) 
±2 dB (1.8 to 6 GHz) 
100 nW/cm² to 265 mW/cm² (CW) 
100 nW/cm² to 325 µW/cm² (True RMS) 
±3 dB (> 6 GHz) 
(e) 
±1 dB (<400 MHz) 
±1.5 dB (400 MHz to 1.8 GHz) 
±1 dB (≥ 1.8 GHz) 
±3 dB (0.8 to 1.65 V/m) 
±1 dB (1.65 to 3.3 V/m) 
±0.5 dB (3.3 to 300 V/m) 
±0.8 dB (300 to 1000 V/m) 
(f) 
±1 dB (27 MHz to 1 GHz) 
±3 dB (170 to 720 nW/cm²) 
±1 dB (720 nW/cm² to 2.9 µW/cm²) 
±0.5 dB (2.9 µW/cm² to 24 mW/cm²) 
±0.8 dB (24 to 265 mW/cm²) 
±2 dB (1 GHz to 18 GHz) 
3/ 10/ 27.12/ 100/ 200/ 300/ 500/ 750 MHz 
1/ 1.8/ 2.45/ 3/ 4/ 5/ 6/ 7/ 8.2/ 9.3/ 10/ 11/ 18 GHz 
0 °C to +50 °C 
-40 °C to +70 °C 
ORDERING INFORMATION 
Probe EF1891, E-Field for NBM, 3 MHz – 18 GHz, Isotropic  2402/02 
Narda Safety Test Solutions GmbH 
Sandwiesenstrasse 7 
72793 Pfullingen, Germany 
Phone: +49 (0) 7121-97 32-777 
Fax: +49 (0) 7121-97 32-790 
E-Mail: support@narda-sts.de 
www.narda-sts.de 
® Names and Logo are registered trademarks of Narda Safety Test Solutions GmbH and L3 Communications Holdings, Inc. - Trade names are trademarks of the owners. 
NSTS 0312-E0234C-0.0  2 / 2  Subject to change 
Narda Safety Test Solutions 
435 Moreland Road 
Hauppauge, NY 11788, USA 
Phone: +1 631 231-1700 
Fax: +1 631 231-1711 
E-Mail: NardaSTS@L-3COM.com 
www.narda-sts.com 
Narda Safety Test Solutions Srl 
Via Leonardo da Vinci, 21/23 
20090 Segrate (Milano), Italy 
Phone: +39 02 2699871 
Fax: +39 02 26998700 
E-mail: support@narda-sts.it 
www.narda-sts.it 
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