Compact Log Periodic Antenna

• Frequency Range: 300 MHz to 1 GHz (useable from 200 MHz)
• Polarization: Linear
• Nominal Impedance: 50 Ohm
• Power Handling: 50 Watts Continuous
• Connector: N-type(female)
• Specifications: FCC, CISPR, EN, ETSI, FAA, Mil-Std, Automotive, etc.
• Dimensions (L x W x H): 21.5” x 5.1” x 25.5” [54.6 x 13 x 64.8 cm]

ALC-100 Compact Log Periodic Antenna FAQs

What frequency range does the ALC-100 cover and where is it most effective in EMC testing?

The ALC-100 covers 300 MHz to 1 GHz and is usable from 200 MHz. In practical EMC work, it is most effective from 300 MHz to 1 GHz, where it provides strong broadband performance for radiated emissions measurements, engineering investigations, and many qualification-level compliance test setups.

Why would an EMC engineer choose the ALC-100 instead of a larger log periodic antenna?

The ALC-100 is a compact log periodic antenna, so it is easier to position inside smaller semi-anechoic chambers, engineering labs, benchtop pre-compliance areas, and temporary troubleshooting setups. Its reduced length helps when space is limited, while still giving broadband coverage needed for real-world EMC measurements.

What types of EMC tests is the ALC-100 commonly used for in real laboratory environments?

The ALC-100 is commonly used for radiated emissions measurements, engineering pre-compliance scans, product troubleshooting, site comparisons, shielding effectiveness evaluations, field monitoring, and normalized site attenuation work. In real laboratory use, it fits well in both formal compliance environments and flexible in-house development test areas.

Which EMC standards and test programs can use the ALC-100 antenna?

The datasheet identifies use with standards and programs such as FCC, CISPR, EN, ETSI, FAA, MIL-STD-461, SAE automotive requirements, RTCA DO-160, and FDA-related qualification work. That makes the ALC-100 useful for laboratories supporting commercial electronics, aerospace, defense, automotive, and regulated product development.

How does the ALC-100 improve in-house EMC pre-compliance testing during product development?

For in-house pre-compliance testing, the ALC-100 helps engineers detect radiated emissions issues early, before sending a product to an outside compliance lab. By scanning prototypes, subassemblies, cable layouts, and enclosure configurations during development, teams can find likely failure frequencies sooner and reduce redesign time, outside lab cost, and schedule risk.

What does a typical ALC-100 radiated emissions pre-compliance setup look like?

A typical setup uses the ALC-100 on an antenna tripod or mast, connected to a spectrum analyzer, EMI receiver, or preamplifier chain. The device under test is placed on a non-conductive table or test surface, and engineers sweep frequencies while adjusting antenna height, polarization, cable routing, grounding, and product operating modes. This setup is especially valuable for fast engineering comparisons before formal chamber testing.

How does the ALC-100 help engineers troubleshoot real EMC problems on prototypes and finished products?

The antenna helps engineers identify which frequencies are radiating, how emissions change when cables move, and whether shielding, filtering, grounding, or enclosure modifications improve performance. In practice, it is useful for isolating noisy subsystems, comparing board revisions, checking the effect of ferrites, and determining whether a product is likely to pass radiated emissions testing.

Can the ALC-100 be used for radiated immunity work, and what are its limits in that role?

Yes. The ALC-100 can be used with RF power amplifiers up to 50 watts to generate RF fields for engineering immunity testing and moderate-field applications. However, for higher-power immunity requirements, Com-Power positions the ALP-100 as the better choice. That makes the ALC-100 more suitable for lighter field generation, development checks, and selected immunity setups rather than the highest-power test systems.

How does the ALC-100 compare with the ALP-100 in real EMC test planning?

The ALC-100 is the better choice when the priority is compact size, convenient chamber positioning, emissions testing, and flexible in-house engineering work. The ALP-100 is better when the application requires substantially higher RF power for demanding radiated immunity field generation. In practical terms, the ALC-100 supports efficient measurement workflows, while the ALP-100 supports more aggressive high-power setups.

Why is a log periodic antenna like the ALC-100 useful for broadband EMC measurements?

A log periodic antenna gives wide frequency coverage with one antenna, so engineers do not need to change antennas repeatedly across the band. This saves setup time, improves repeatability, and makes automated sweeps easier. For in-house EMC work, that means faster comparisons between design changes and quicker identification of troublesome frequency regions.

What gain and antenna factor characteristics does the ALC-100 provide, and why do they matter?

The ALC-100 has typical isotropic gain from about 2.1 to 7.8 dBi and antenna factor from about 13.3 to 23.2 dB(m-1). These values matter because they help convert measured voltage into field strength and support more accurate interpretation of emissions data. For engineering teams, this makes the antenna useful not just for detecting a problem, but for evaluating how serious the problem is.

What polarization does the ALC-100 support, and why is fast polarization change important in EMC testing?

The ALC-100 is linearly polarized and uses a hinge mechanism that allows quick switching between horizontal and vertical polarization. This is important because emissions and susceptibility can vary significantly with antenna orientation. Fast polarization changes improve test efficiency and help engineers capture worst-case behavior without rebuilding the setup.

What impedance and connector configuration does the ALC-100 use, and how does that help lab integration?

The antenna uses a 50-ohm nominal impedance and a Type-N female connector. This makes it easy to integrate with common EMC lab components such as RF cables, preamplifiers, EMI receivers, spectrum analyzers, and power amplifiers. In real-world use, that standard interface reduces setup friction and makes the antenna easier to move between different test benches or chambers.

How is the ALC-100 calibrated, and why is that important for compliance-oriented measurements?

Each ALC-100 antenna is individually calibrated per ANSI C63.5 with NIST traceability, and calibration data is provided with the antenna. This is important because engineers and laboratories need confidence that measured results are repeatable and defensible. Calibration supports better correlation between in-house engineering measurements and final accredited compliance testing.

How can the ALC-100 be used for NSA, site comparison, and chamber validation work?

A pair of ALC-100 antennas can be used instead of tuned dipoles for normalized site attenuation calibration of open area test sites or semi-anechoic chambers. This avoids the slow process of tuning dipole lengths at each discrete frequency. The antenna is also useful for site comparisons and chamber checks when engineers want a broadband tool for verifying test environment consistency.

How can the ALC-100 be used for shielding effectiveness testing and enclosure evaluation?

The ALC-100 can be used to transmit or receive RF energy when evaluating the shielding performance of cabinets, enclosures, rooms, and large equipment housings. In practical engineering use, this helps teams compare gasket designs, seams, door treatments, enclosure coatings, and bonding methods to see which design changes reduce leakage most effectively.

What construction and mounting features make the ALC-100 practical for daily lab use?

The antenna is built for durability, with solid stainless-steel elements and heavy-gauge corrosion-resistant aluminum feeder tubes. It also includes a standard 1/4-inch x 20 mounting hole for use with tripods, masts, and similar mounting structures. These features make it practical for repeated indoor and outdoor use, routine lab handling, and frequent repositioning during EMC investigations.