Com-Power ALT-930-2M 9 kHz to 30 MHz Triple Loop Antenna

Key Features At A Glance

• Frequency range 9 kHz to 30 MHz for radiated magnetic field disturbance measurements
• Three mutually perpendicular insulated 2-meter diameter loops constructed per CISPR 16-1-4
• Designed for compliance testing per CISPR 15 / EN 55015 radiated disturbance limits
• Includes CS-450 four-channel coaxial switch that selects the active loop and terminates the other two into 50 ohms
• Output port impedance of 50 ohms with female BNC connector for connection to spectrum analyzer or EMI receiver
• Fiber glass and plastic mounting structure with swivel casters for positioning
• Accommodates devices under test up to approximately 1.6 meters in overall length
• Optional ALT-930-CKIT calibration kit and optional RLI-100 fiber optic remote interface for the CS-450 switch

The Com-Power ALT-930-2M is a triple loop antenna system designed for measurement of radiated electromagnetic disturbances over the frequency range of 9 kHz to 30 MHz. The system consists of three mutually perpendicular insulated loops, each 2 meters in diameter, constructed from RG 223/U coaxial cable housed in 1-inch PEX pipe. Each loop connects in series with a current-to-voltage transducer, and the three transducer outputs feed a CS-450 four-channel coaxial switch that selects the active loop while terminating the other two into 50 ohms.

The primary application identified by the manufacturer is measurement of radiated magnetic fields generated by electrical lighting and similar equipment placed in the approximate center of the triple loop structure. The antenna is designed based on the Loop Antenna System (LAS) described in Annex C of CISPR 16-1-4, and measurement results are compared against the radiated disturbance limits defined in CISPR 15 / EN 55015. The equipment under test is mounted on a non-conductive stand inside the loop volume, and fields are measured successively in the three orthogonal axes by switching between loops.

ValueTronics International, LLC stocks, inspects, and ships test and measurement equipment such as the Com-Power ALT-930-2M from its 20,000 sq ft secure warehouse at 1675 Cambridge Drive, Elgin, Illinois. Operating since 1992, ValueTronics maintains in-house technical staff who handle and test instrumentation directly rather than drop-shipping from third-party warehouses, giving customers a single point of contact for sales, technical questions, calibration coordination, and post-sale support on this triple loop antenna system.

Compare Other Models in This Series

The ALT-930 family from Com-Power covers loop antenna systems and the accessories used to calibrate them per CISPR 16-1-4 Annex C. The ALT-930-2M is the 2-meter diameter triple loop antenna itself, while the ALT-930-CKIT is the matching calibration kit built around a balun-dipole transmit antenna and its mounting structure.

Both items are documented together in a single Com-Power instruction manual because the calibration kit's balun-dipole is the transmit antenna specifically defined for validating the triple loop antenna across its 9 kHz to 30 MHz operating range. The triple loop antenna is the measurement instrument; the calibration kit is the verification tool.

Each new ALT-930 family product is listed on its own product page with condition-matched pricing and availability. The ALT-930-2M triple loop antenna and the ALT-930-CKIT calibration kit are sold separately; review each linked page for current configuration details, included accessories, and shipping information.

Within the ALT-930 family, the ALT-930-2M is the measurement antenna: three 2-meter diameter loops, three current-to-voltage transducers, the CS-450 four-channel coaxial switch, and the full mounting structure. It is the item that goes on the test floor for CISPR 15 / EN 55015 radiated disturbance measurements on lighting and similar equipment.

The ALT-930-2M and ALT-930-CKIT differ in role and frequency-relevant construction. The ALT-930-2M uses three large 2-meter loops to receive magnetic fields generated by the equipment under test placed inside the loop volume. The ALT-930-CKIT uses a much smaller 1.5 by 0.1 by 0.006 meter balun-dipole as a transmitting antenna, placed at the geometric center of the triple loop, to inject a known signal for the calibration procedure.

The two items also differ in overall envelope and weight. The ALT-930-2M assembled dimensions are 2.54 by 2.1 by 2.1 meters at 65.5 lb (29.7 kg); the ALT-930-CKIT assembled dimensions are 1.56 by 1.5 by 0.5 meters at 25 lb (11.34 kg). Both share the same 9 kHz to 30 MHz frequency range, 50-ohm impedance, and female BNC connectors, and both reference CISPR 16-1-4 as the governing construction standard. See the comparison table below for the specifications side by side.

Model	Frequency Range	Loop Diameter	Standard
ALT-930-2M	9 kHz to 30 MHz	2 meters	CISPR 16-1-4, CISPR 15
ALT-930-CKIT	9 kHz to 30 MHz	1.5 x 0.1 x 0.006 meters (Balun-Dipole)	CISPR 16-1-4

Additional differences in specifications beyond the few shown above are not listed here — see each model's full specifications below.

Accessories Supplied

• (3) 2-meter diameter insulated loops with male N-connectors
• (3) Current to voltage transducers
• (1) CS-450 Four-Channel Coaxial Switch
• (3) 2-meter coaxial cable assemblies with molded ferrites and male BNC connectors
• (1) 8-meter coaxial cable assembly with male BNC connectors
• (1) Central support hub with swivel caster
• (4) Corner base supports with swivel caster, vertical post & dual loop clamp
• (1) 0.5-meter vertical center post with dual loop clamp
• (4) 1-meter horizontal support beams
• (1) Top dual loop clamp

Product Core & Specifications

Specification	Value
Frequency Range	9 kHz to 30 MHz
Standard(s)	CISPR 16-1-4, CISPR 15
Loops	(3) independent, insulated loops, switchable
Diameter of Loops	2 meters
Loop Construction	RG 223/U Coaxial Cable in 1" PEX pipe
Output Port Impedance	50 ohms
Output Connector	Coaxial BNC (female)
Mounting Structure Construction	Fiber Glass/Plastic
Weight	65.5 lbs. (29.7 kg)
Overall Dimensions (H)x(W)x(D)	2.54 x 2.1 x 2.1 meters
Operating Temperature	0° C to 40° C

Important: The 150 kHz high-pass filter on the CS-450 coaxial switch is not intended to be used with the ALT-930-2M and should remain in the OFF position. In the ON position, the filter attenuates signals between 9 kHz and 150 kHz, rendering measurements within that band invalid.Important: The 150 kHz high-pass filter on the CS-450 Coaxial Switch is not intended to be used in conjunction with the ALT-930-2M Triple Loop Antenna, and should remain in the OFF position. In the ON position, the filter will attenuate any signals present between 9 kHz and 150 kHz, rendering any measurements within that band invalid.Important: The ALT-930-CKIT Calibration Kit is an optional item and is not included with the standard ALT-930-2M Triple Loop Antenna. It must be ordered separately if balun-dipole calibration capability is required.Important: The RLI-100 Remote Switch with Fiber Optic Interface is an optional item and is not included with the standard ALT-930-2M Triple Loop Antenna. It must be ordered separately for remote operation of the CS-450 Coaxial Switch.Important: The ALT-930-2M can be used to perform tests on devices not exceeding an overall length of 1.6 meters.Recommended pairing: the optional ALT-930-CKIT Calibration Kit provides the CISPR 16-1-4 balun-dipole transmit antenna and mounting structure required to perform the 24-position calibration procedure described in the ALT-930-2M manual. The optional RLI-100 Remote Interface enables fiber-optic remote control of the CS-450 four-channel coaxial switch.

Please review the Manufacturer's Data Sheet to verify published specifications. Feedback on this webpage is always welcome — please reach out to your Test Architect at any time for questions or concerns. Thank you, we truly appreciate you being our customer.