TEKBOX TBMA5 Active Monopole Antenna Owner’s Manual
- June 25, 2024
- TEKBOX
Table of Contents
V1.0
TBMA5
Active Monopole Antenna
Introduction
The TBMA5 is an active Monopole Antenna, expanding the Tekbox product range of affordable EMC pre-compliance test equipment. The monopole antenna is designed for radiated emission measurements within the frequency range 9 kHz 30 MHz, according to CISPR 16. The monopole antenna has a rod with height of 104 cm and provides sufficient sensitivity to carry out radiated emission measurements as specified in CISPR 25 or MIL-STD-461G.
The TBMA5 consists of an impedance converter, a universal charger, a 10 mm diameter rod, a 60 cm x 60 cm ground plane and a standard 10pF calibration adapter. Furthermore, it includes the coaxial cable with ferrite and grounding equipment required under MIL-STD461G. The impedance converter is equipped with a ¼” thread to attach it to conventional tripods.
Specification
Characterized frequency range: | 9 kHz to 30 MHz |
---|---|
Electric field antenna factor: | +6 to +7 dB/m, typ. |
Antenna factor variation: | < ±0.8 dB, typ. |
Dynamic Range: | 118 dB @ 1MHz, 1 KHz bandwidth |
Electric field, lower limit: | 12 dBµV/m (4.0 µV/m) @ 1MHz, 1 KHz bandwidth |
Electric field, upper limit: | 130 dBµV/m (3.15 V/m) @ 1 dB compression |
Output VSWR: | 1.02 to 1.52 (average:1.06) :1 |
Output connector type: | N female |
Battery type: | 6 x NiMH, AA (not included) |
Battery life on average: | 20 hours |
Charger: | Ansmann ACS310 |
Tripod mount: | ¼” thread |
Impedance converter dimensions: | 185 x 210 x 65 mm, 1.5 kg |
Carrying Case: | Aluminum, 75 x 73 x 18 cm, 4 kg |
Antenna factor
The antenna factor AF is an antenna and frequency dependent parameter, which is required to convert the voltage measured at the output of an antenna into the corresponding electric field strength. For electric field strength:
E[dBµV/m] = V[dBµV] + AFE[dB/m] Where AFE is the electric antenna factor in [dB/m]
Antenna factor table
Frequency [MHz| Electric field antenna factor
[dB/m]| Magnetic field antenna factor
[dB/Ωm]| Uncertainty [dB]
---|---|---|---
0,009| 6.71| -44.79| ±1.00
0,010| 6.64| -44.86| ±1.00
0,020| 6.39| -45.11| ±1.00
0,030| 6.34| -45.16| ±1.00
0,040| 6.32| -45.18| ±1.00
0,050| 6.3| -45.2| ±1.00
0,060| 6.29| -45.21| ±1.00
0,070| 6.29| -45.21| ±1.00
0,080| 6.28| -45.22| ±1.00
0,090| 6.28| -45.22| ±1.00
0,100| 6.28| -45.22| ±1.00
0,110| 6.27| -45.23| ±1.00
0,120| 6.27| -45.23| ±1.00
0,130| 6.27| -45.23| ±1.00
0,140| 6.26| -45.24| ±1.00
0,150| 6.26| -45.24| ±1.00
0,200| 6.26| -45.24| ±1.00
0,300| 6.26| -45.24| ±1.00
0,400| 6.26| -45.24| ±1.00
0,500| 6.26| -45.24| ±1.00
0,600| 6.25| -45.25| ±1.00
0,700| 6.24| -45.26| ±1.00
0,800| 6.24| -45.26| ±1.00
0,900| 6.23| -45.27| ±1.00
1,000| 6.23| -45.27| ±1.00
2,000| 6.22| -45.28| ±1.00
3,000| 6.22| -45.28| ±1.00
4,000| 6.21| -45.29| ±1.00
5,000| 6.21| -45.29| ±1.00
6,000| 6.19| -45.31| ±1.00
7,000| 6.19| -45.31| ±1.00
8,000| 6.18| -45.32| ±1.00
9,000| 6.18| -45.32| ±1.00
10,000| 6.18| -45.32| ±1.00
11,000| 6.18| -45.32| ±1.00
12,000| 6.19| -45.31| ±1.00
13,000| 6.2| -45.3| ±1.00
14,000| 6.21| -45.29| ±1.00
15,000| 6.23| -45.27| ±1.00
16,000| 6.24| -45.26| ±1.00
17,000| 6.26| -45.24| ±1.00
18,000| 6.29| -45.21| ±1.00
19,000| 6.31| -45.19| ±1.00
20,000| 6.33| -45.17| ±1.00
21,000| 6.36| -45.14| ±1.00
22,000| 6.39| -45.11| ±1.00
23,000| 6.41| -45.09| ±1.00
24,000| 6.45| -45.05| ±1.00
25,000| 6.48| -45.02| ±1.00
26,000| 6.51| -44.99| ±1.00
27,000| 6.55| -44.95| ±1.00
28,000| 6.58| -44.92| ±1.00
29,000| 6.62| -44.88| ±1.00
30,000| 6.66| -44.84| ±1.00
Table 1: TBMA5 antenna factors, 9 kHz 30 MHz, typical values
VSWR
Calibration
The TBMA5 already comes with a factory calibration protocol. The calibration
accessory enables periodic re-calibration or validation of the performance, if
required. The calibration process for obtaining the antenna factor is based on
the Equivalent Capacitance Substitution Method (ECSM). It is a two-step
procedure:
– Normalizing procedure
As shown in the picture below, both 50 RF ports of a vector network
analyzer/spectrum analyzer are connected to both sides of a coaxial T adapter,
combined with two 10 dB N-type
Active Monopole Antenna
attenuators in order to improve matching of the VNA ports. The 10 pF
calibration capacitor, which is attached to the input port of the impedance
converter to simulate the high impedance of the 104cm rod element of the TBMA5
antenna. A 50 termination is connected to the output port of the antenna for
the normalization purpose. Next, a S21 Through Calibration is carried out
within the frequency range of the antenna.
– Measurement procedure
For the measurement procedure as shown in the picture below, the RF input port
of the vector network analyzer/spectrum analyzer (port 2) is now detached from
the coaxial T adapter and is connected to the output port of the TBMA5 antenna
while it is still attached to the 10 dB Ntype attenuator. The 50 termination
load is now connected to the coaxial T adapter. Next carry out a S21
measurement, which represents the gain of the impedance converter.
Using the described method, the antenna amplifier gain and the active antenna
factor can be calculated using the following equations respectively:
Amplifier Gain = S21 (Impedance Converter) [dB] Antenna Factor = 6.02 –
Amplifier Gain [dB/m]
Sensitivity
The sensitivity of a radiated noise measurement setup looks at the base noise
of the available spectrum analyzer or measurement receiver. Applying the
antenna factor gives the resulting minimum detectable electric field for the
active monopole antenna. this noise floor has to be at least 6 dB below the
emission limits of the applied standard.
To measure the sensitivity of the antenna @ 1MHz and 1KHz RBW, the minimum
signal should be at least 6 dB above the noise floor of the available spectrum
analyzer /measurement receiver in order to be clearly distinguishable from the
noise level according to CISPR 16 standard.
Accessories
The TBMA5 comes in an aluminum carrying case and includes the impedance converter, a universal charger, a ground panel, a rod, a calibration adapter and a MIL-STD-461G ground bonding kit consisting of a 125cm long coaxial cable with ferrite sleeve and a ground bonding adapter.
Inserting / replacing batteries
Due to airfreight regulations the TBMA5 does not include rechargeable
batteries. Before operation, it is necessary to insert 6 pieces standard 1.2V
NiMH batteries.
Remove the four screws at the bottom base plate of the impedance converter
housing, lift it, and insert six AA rechargeable 1.2V NiMH batteries. Both the
battery compartment and the PCB indicate the polarity. Re-attach the bottom
base plate, then tighten the screws.
Ordering Information
Part Number | Description |
---|---|
TBMA5 | TBMA5 impedance converter, Ansmann ACS310 universal charger, 104 cm |
rod, 60 cm x 60 cm ground panel, 10 pF calibration adapter, coaxial T-adapter,
2 pcs 10 dB attenuators, Mil-STD-461 ground bonding kit consisting of a 125 cm
long 50 Ohm coaxial cable, a ferrite sleeve and a ground bonding adapter
Aluminum carrying case
NIST traceable factory calibration certificate & report
History
Version | Date | Author | Changes |
---|---|---|---|
V 1.0 | 21.03.2024 | Mayerhofer | Creation |
www.tekbox.com
TekBox Digital Solutions Vietnam Pte. Ltd.
Factory 4, F4, Lot I-3B-1, Saigon Hi-Tech Park, Tan Phu Ward, District 9, Ho
Chi Minh City, Vietnam