Atec EMCO-3101, EMCO-3102, EMCO-3103 User Manual
Model 3101
200 MHz – 1 GHz
Model 3102
1 GHz – 10 GHz
● Circular Polarization
● Extremely Low VSWR
● Compact Size
MODEL 3101
Conical Log Spiral
EMCO’S BROADBAND CONICAL LOG SPIRAL ANTENNAS show
minimal pattern change over their wide operating frequency
range of 100 MHz to 10 GHz. All antennas in this series have
moderate gain and low VSWR. Three models offer you a choice
in size, frequency range, and polarization.
Once used exclusively for MIL-STD and SAE testing, conical
log spiral antennas are effective for other types of measurements too. For example they can be used for close-in “quicklooks” to find the spectral characteristics of RF emissions. For
immunity testing , conical log spirals generate reasonable field
strengths with modest power input. By placing conical log
spiral antennas in a vertical position with respect to the ground
plane, they also can be used as omni-directional, horizontally
polarized antennas for electromagnetic site surveys.
EMCO Conical Log Spiral Antenna Features
Circular or Linear Polarization
EMCO’s conical log spiral antennas will receive both circular
polarized and linear polarized fields (with a 3 dB variance for
linear fields) under normal operating conditions.
Low VSWR
Average VSWR for the Model 3101 is 2.4:1. The Model 3102
averages a 1.6:1 VSWR and the Model 3103 averages
1.9:1 VSWR.
Model 3103
100 MHz – 1 GHz
Quality Construction
● Unique Applications
● Quality Construction
EMCO’s conical log spiral antennas are made with spiral
windings of coaxial cable attached to the outside of a fiberglass
cone. Outside windings improve heat dissipation. This cone is
attached to a delrin rod equipped with an aluminum base. The
antenna mounting base accepts standard 1/4 in x 20 threads
from an EMCO tripod or most other tripods.
Choosing Your Model: Three Models
with Frequency Ranges of 100 MHz to 10 GHz
100 MHz to 1 GHz
The Model 3103 conical log spiral antenna is similar to Models
3101 and 3102 except that it has the lowest frequency range
and it is largest in size. Length is 102.0 cm (40 in) diameter is
66.0 cm (26.0 in). The design is patterned on NASA drawings.
200 MHz to 1 GHz
The Model 3101 conical log spiral antenna was designed by
the Department of Defense for MIL-STD-461E measurements.
The original drawings provide the basis for our Model 3101.
Length is 81.3 cm (32.0 in) and diameter is 33.0 cm (13.0 in).
1 to 10 GHz
The Model 3102 conical log spiral antenna is similar to the
Model 3101 but has a higher frequency range and is smaller in
size. Length is 38.1 cm (15 in) and diameter is 12.7 cm (5.0 in).
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5656
Compact Size
The compact size of EMCO’s conical log spiral antennas makes
them ideal for use in anechoic chambers and shielded
enclosures where space is limited and proximity effects must
be minimized.
USA:
Tel +1.512.531.6400
Fax +1.512.531.6500
FINLAND:
Tel +358.2.838.3300
Fax +358.2.865.1233
UK:
Tel +44.(0)1438.730.700
Fax +44.(0)1438.730.750
Tel +65.536.7078
Fax +65.536.7093
ONLINE:SINGAPORE:
info@ets-lindgren.com
www.ets-lindgren.com
Standard Configuration
f y i
◗ Left-hand circular polarization
◗ Support rod
◗ Base drilled to accept EMCO or other tripod mount with
standard 1/4 in x 20 threads
◗ Individually calibrated at 1 m per SAE ARP 958.
Actual factors and a signed Certificate of Calibration
Conformance included in Manual.
Options
Right-hand circular polarization
This option reverses the antenna windings for right-hand
polarization.
Custom cases
Custom cases are available on request.
EMCO Tripod
EMCO offers several non-metallic, non-reflective tripods for
use at EMC test sites.
Applications
MODELMODEL
MODEL
MODELMODEL
11
1
11
31013101
3101
31013101
1
31023102
3102
31023102
1
31033103
3103
31033103
RE = Radiated Emissions RI = Radiated Immunity (Susceptibility)
SAE J1113SAE J1113
SAE J1113
SAE J1113SAE J1113
RI RE, RI RE
RI RE, RI RE
RI RE, RI RE
The Conical Log Spiral antenna first came to the attention of
the EMC community when it was listed as the preferred
antenna for radiated emissions measurement in MIL-STD826A, 20 Jan. 1964. At the time, this antenna was righthand circularly polarized, following to the definitions in
standards of the day. Per modern definitions, the original
Model 3101 is left-hand circularly polarized (e.g. when
observed along the direction of propagation, the rotation of
the wave is counterclockwise, while the wave is left-hand
circularly polarized). By modern definitions, EMCO's optional
Model 3101L is right-hand circularly polarized. The current
model numbers remain unchanged for reasons of continuity,
but the description of their performance has changed to
reflect modern definitions.
MIL-STD-461EMIL-STD-461E
MIL-STD-461E
MIL-STD-461EMIL-STD-461E
MIL-STD-1541MIL-STD-1541
MIL-STD-1541
MIL-STD-1541MIL-STD-1541
Conical Log Spira l
Electrical Specifications
MODELMODEL
MODEL
MODELMODEL
31013101
3101
31013101
31023102
3102
31023102
31033103
3103
31033103
1
1
1
FREQUENCYFREQUENCY
FREQUENCY
FREQUENCYFREQUENCY
RANGERANGE
RANGE
RANGERANGE
20 0 MHz – 1 GHz 2.4:1 1 00 W 15 0 W 50 Ω Type N female
1 GHz – 10 GHz 1.6:1 50 W 10 0 W 50 Ω Type N female
10 0 MHz – 1 GHz 1.9:1 1 00 W 1 50 W 50 Ω Type N female
Physical Specifications
MODELMODEL
MODEL
MODELMODEL
1
31013101
3101
31013101
1
31023102
3102
31023102
1
31033103
3103
31033103
1
Speciality Item. Call EMCO for lead time and pricing.
DEPTHDEPTH
DEPTH
DEPTHDEPTH
81.3 cm 33.0 cm 4.5 kg
32.0 in 13.0 in 10.0 lb
38.1 cm 12.7 cm 3.6 kg
15.0 in 5.0 in 8.0 lb
102.0 cm 66.0 cm 10.0 kg
40.0 in 26.0 in 22.0 lb
VSWRVSWR
VSWR
VSWRVSWR
RATIORATIO
RATIO
RATIORATIO
(AVG)(AVG)
(AVG)
(AVG)(AVG)
MAXIMUMMAXIMUM
MAXIMUM
MAXIMUMMAXIMUM
CONTINUOUSCONTINUOUS
CONTINUOUS
CONTINUOUSCONTINUOUS
POWERPOWER
POWER
POWERPOWER
DIAMETERDIAMETER
DIAMETER
DIAMETERDIAMETER
PEAKPEAK
PEAK
PEAKPEAK
POWERPOWER
POWER
POWERPOWER
IMPEDANCEIMPEDANCE
IMPEDANCE
IMPEDANCEIMPEDANCE
CONNECTORCONNECTOR
CONNECTOR
CONNECTORCONNECTOR
WEIGHTWEIGHT
WEIGHT
WEIGHTWEIGHT
USA:
Tel +1.512.531.6400
Fax +1.512.531.6500
FINLAND:
Tel +358.2.838.3300
Fax +358.2.865.1233
UK: ONLINE:
Tel +44.(0)1438.730.700
Fax +44.(0)1438.730.750
SINGAPORE:
Tel +65.536.7078
Fax +65.536.7093
info@ets-lindgren.com
www.ets-lindgren.com
5757
57
5757
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