Half-Wave Tuned Dipole Antenna Kit for EMI & EMC Testing
The gold standard ANSI C63.5 reference antenna for site validation, broadband antenna calibration, NSA measurements, and discrete frequency compliance testing across 30 MHz to 1 GHz. The AD-100 V2.0 is the only antenna type mandated by ANSI C63.4 and CISPR 16-1-4 for these critical applications.
Frequently Asked Questions: Dipole Antenna Set
What is a half-wave tuned dipole antenna and why is it used as a reference antenna?
A half-wave tuned dipole antenna consists of two conductive elements of equal length — each a quarter-wavelength long — with a balun at the feed point. Because its radiation pattern, impedance, and antenna factor are all theoretically calculable and reproducible, it serves as the primary reference against which all other antennas are compared. Per ANSI C63.4 and CISPR 16-1-4, the half-wave dipole is the only antenna type accepted for calibrating broadband antennas, validating test sites via NSA measurements, and making discrete frequency compliance measurements. No broadband antenna type (biconical, log-periodic, horn) can substitute for this role.
What does the AD-100 V2.0 kit include and what frequency range does it cover?
The AD-100 V2.0 covers 30 MHz to 1000 MHz using four frequency-specific baluns: DB1 (30–65 MHz), DB2 (65–180 MHz), DB3 (180–400 MHz), and DB4 (400–1000 MHz). The complete kit includes all four baluns with their integral or attachable elements, 300mm and 700mm fixed extension elements (2 and 4 pieces respectively), collapsible long and short element sets, a 22mm tripod clamp (ATC-22M-AD), and a rugged carry/storage case. Elements are adjustable (tunable) to the exact half-wavelength length at each test frequency per the ANSI C63.5 length tables.
Does the AD-100 V2.0 require calibration?
No — per ANSI C63.4 and CISPR 16-1-4, half-wave dipoles do not require periodic calibration. Antenna factors are calculated directly from the ANSI formula: AF (dB/m) = 20 × log10(freq. in MHz) − 31.4 + 0.5 dB (averaged balun loss). Each balun's insertion loss is individually verified at the factory. NIST-traceable and ISO 17025 accredited calibration are available upon request for labs whose quality management systems require an externally accredited calibration certificate. The self-calculable nature of the dipole's antenna factor is one of its major advantages over broadband antennas.
What EMC standards require or reference the AD-100 V2.0?
The AD-100 V2.0 is designed per Appendix E of ANSI C63.5 and supports testing under ANSI C63.4 (methods for radiated emissions measurements), CISPR 16-1-4 (antennas and test sites), FCC Part 15, FCC Part 18, CISPR 11, CISPR 25, CISPR 32, MIL-STD-461 RE102, IEC 61000-4-3 (for field uniformity validation), and equivalent CE/EN and VCCI standards. Wherever discrete frequency radiated measurements or NSA site calibration are required by these standards, the half-wave dipole is the mandated reference antenna.
How do I calculate antenna factors and field strength using the AD-100 V2.0?
Antenna factor is calculated as: AF (dB/m) = 20 × log10(freq. in MHz) − 31.4 + balun loss (typically 0.5 dB). Field strength is then: E (dBμV/m) = Vreceiver (dBμV) + AF (dB/m). For EIRP testing, isotropic gain ≈ 1 dBi across the operating range. At 30 MHz AF ≈ −1.3 dB/m; at 100 MHz ≈ 9.1 dB/m; at 500 MHz ≈ 22.0 dB/m; at 1000 MHz ≈ 29.1 dB/m. The datasheet and manual include a full frequency-versus-element-length table for precise tuning at each test frequency.
What is NSA (Normalized Site Attenuation) and why does it require a dipole?
NSA is the measured difference in signal between a transmitting and receiving antenna at a test site, normalized to theoretical free-space values. It is used to validate that an OATS or semi-anechoic chamber meets the ±4 dB site attenuation tolerance specified in ANSI C63.4 before it can be used for official compliance testing. NSA measurements must be performed using half-wave dipole antennas — not broadband antennas — because only the dipole's calculable characteristics allow a valid comparison to the theoretical NSA values derived from standard formulas. The AD-100 V2.0 is commonly used in pairs (transmit and receive) for NSA measurements at 3m, 10m, and 30m test distances.
Can the AD-100 V2.0 be used for ERP and EIRP measurements of intentional radiators?
Yes. The AD-100 V2.0 is the standard substitution antenna for measuring Effective Radiated Power (ERP) and Effective Isotropic Radiated Power (EIRP) of intentional radiators (transmitters) per FCC Part 15, FCC Part 22, and similar international regulations. The transmitter under test is replaced by the dipole energized to produce an equivalent received signal level at the measurement receiver — the known antenna factor of the dipole then gives the field strength, which converts directly to radiated power. This substitution method is required for transmitters that cannot have their power measured directly at the antenna terminal.
What is the difference between the AD-100 V2.0 and the older AD-100A?
The AD-100 V2.0 is a major redesign of the discontinued AD-100A. Key improvements include updated balun designs with individually verified insertion loss, redesigned collapsible element systems for easier field assembly and more precise tuning, updated documentation aligned to the current ANSI C63.5 edition, and improved mechanical durability. The V2.0 balun part numbers (ABAL-AD100-DB1 through DB4 V2.0) are different from the AD-100A baluns. Both datasheets and manuals for the V2.0 and the legacy AD-100A are available in the Documentation tab for reference.
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What Is a Dipole Reference Antenna?
A dipole antenna consists of two conductive elements of equal length extending in opposite directions from a central feed point. A half-wave dipole has a total length equal to approximately half the wavelength of its operating frequency, with each element at quarter-wavelength. At resonance this creates predictable radiation characteristics: a figure-eight pattern in the plane perpendicular to the elements, approximately 73-ohm free-space impedance (matched to 50 ohms via a balun), and an isotropic gain of approximately 2.15 dBi (≈1 dBd).
What makes the dipole uniquely valuable in EMC is that its antenna factor can be mathematically calculated rather than experimentally measured. This means it serves as a primary standard — not dependent on calibration against another antenna. Per ANSI C63.5 and CISPR 16-1-4, the half-wave dipole is therefore:
📡 The Reference for Broadband Antenna Calibration
The only acceptable reference antenna for determining antenna factors of biconical, log-periodic, and other broadband antennas using the substitution method.
🏛️ The Mandatory NSA Measurement Antenna
Required for Normalized Site Attenuation measurements that validate OATS and semi-anechoic chambers. No other antenna type is accepted for this purpose.
📊 The Standard for Discrete Frequency Compliance
Required for discrete frequency field strength measurements and ERP/EIRP determination of intentional radiators per FCC, CISPR, and EN standards.
🔢 Calculable Antenna Factors — No Calibration Required
AF = 20 × log(freq. MHz) − 31.4 + balun loss. No periodic recalibration fees or downtime. Traceability is built into the calculation per ANSI C63.5.
