[Home](/)/[Resources](/resources)/EN 300 328 Test Method Deep Dive CE / EUEN 300 328RED # EN 300 328 V2.2.2: Wi-Fi and Bluetooth Test Method Deep Dive for RED Compliance ETSI EN 300 328 V2.2.2 (2019-07) is the harmonised standard manufacturers use to demonstrate Radio Equipment Directive compliance for wideband data transmission devices in the 2.4 GHz band. This guide unpacks the e.i.r.p limits, duty cycle mechanism, Adaptive Frequency Agility requirement, and the test methodology that catches most first-time submitters off guard. Copy Link[Share on WhatsApp](https://wa.me/?text=https%3A%2F%2Fkrono-labs.com%2Fguides%2Fen-300-328-test-standard-deep-dive) At a glance Standard version EN 300 328 V2.2.2 (2019-07) Max e.i.r.p (data) 100 mW / 20 dBm Duty cycle limit 10% per channel / 1 s AFA alternative Yes — replaces duty cycle ## Key technical requirements and concepts ### RED Article 3 obligation categories EN 300 328 addresses two distinct RED essential requirements. Article 3.1(b) covers effective use of radio spectrum to avoid harmful interference — this is where spurious emission limits and frequency accuracy requirements live. Article 3.2 covers efficient use of radio spectrum — duty cycle and Adaptive Frequency Agility (AFA) sit here. Manufacturers must demonstrate compliance with both obligation categories separately in the technical file. ### E.i.r.p limits under Clause 4.3.1 For access probing (beacons, probe requests) the standard caps e.i.r.p at 100 mW (20 dBm). For data transmission the maximum e.i.r.p permitted is also 100 mW for equipment operating across the full 2.4 GHz band (Type 1 equipment). Measurements are conducted e.i.r.p at the antenna port, or radiated TRP for complete equipment where no antenna port is accessible. The 6 dB antenna gain ceiling for directional antennas limits the effective gain that can be added beyond a reference antenna. ### Duty cycle mechanism (non-AFA path) Equipment that does not implement AFA must comply with the duty cycle restriction: no more than 10% channel occupancy over any 1-second observation window, and no more than 100% aggregate across all channels. The 1-second window is a sliding window, not a fixed interval. The test engineer must measure transmitter on-time in the worst-case operational mode — typically maximum throughput — and divide by 1,000 ms. Failing this test on a high-throughput protocol is common; most modern Wi-Fi products use AFA instead. ### Adaptive Frequency Agility (AFA) AFA is the alternative to duty cycle compliance under EN 300 328. Equipment implementing AFA must demonstrate it can detect occupancy on each operating channel and adapt its channel usage accordingly. The standard defines the test method: the equipment is operated on a test channel while interferers are injected on adjacent channels. The DUT must be shown to move away from congested channels within the observation window. AFA effectively eliminates the 10% duty cycle restriction for equipment that passes the AFA test sequence. ### Conducted vs radiated test setup For module-level components with an accessible antenna port, testing is conducted: a cable is attached to the antenna port and the signal is measured directly. For complete products (laptops, routers, IoT devices), radiated Total Radiated Power (TRP) measurements are performed in a shielded anechoic chamber or reverberation chamber per Annex C. Measurement uncertainty requirements are specified in EN 303 786, and the expanded uncertainty must be declared in the test report alongside the measurement result. ### Relationship to EN 300 440 and EN 301 489 EN 300 328 applies specifically to wideband data transmission equipment in the 2.4 GHz ISM band — this covers IEEE 802.11 (Wi-Fi) and Bluetooth (Classic and LE). Short-range devices in the same band that do not implement wideband data transmission may fall under EN 300 440 instead. Spurious domain emissions from EN 300 328 devices are assessed against the limits in EN 301 489-17 (the EMC harmonised standard for radio equipment), which references CISPR 32 conducted and radiated emission limits. ## EN 300 328 compliance process — step by step 01 Classify the product: confirm it falls under EN 300 328 as wideband data transmission equipment in the 2.4 GHz band (802.11b/g/n/ax or Bluetooth Classic/LE). Products using proprietary sub-1 GHz protocols or operating outside 2400–2483.5 MHz use different standards. 02 Determine spectrum access mechanism: decide whether the product implements AFA (adaptive channel selection based on occupancy detection) or relies on the 10% duty cycle mechanism. This choice drives the test plan — AFA products must pass the AFA test sequence in addition to or instead of duty cycle measurement. 03 Engage an ISO/IEC 17025-accredited test laboratory with ETSI EN 300 328 competence. Verify the lab's scope of accreditation explicitly includes V2.2.2 test methods. Major labs include TÜV Rheinland, SGS, Intertek, and Bureau Veritas — all operate EN 300 328-competent RF chambers. 04 Prepare the test setup per Annex C of EN 300 328: configure the DUT at maximum power, maximum data rate, and worst-case antenna configuration. For conducted measurements, use a calibrated attenuator and RF cable matched to the antenna port impedance (typically 50 Ω). 05 Measure e.i.r.p at maximum transmit power. Confirm the access probing e.i.r.p does not exceed 100 mW (20 dBm) and data channel e.i.r.p does not exceed 100 mW. Record the measurement result with expanded uncertainty per EN 303 786. 06 Measure duty cycle compliance (if not implementing AFA): operate the DUT at maximum throughput and record transmitter on-time over a 1-second sliding window. Calculate duty cycle as on-time/1000 ms. Must be ≤10% per channel. 07 If AFA is implemented: run the AFA test sequence. Inject defined interferers on the operating channel and on adjacent channels per the Annex C procedure. Demonstrate that the DUT detects the occupancy and adapts its channel selection within the required observation window. 08 Measure spurious emissions in both conducted and radiated modes. Compare results against the spurious domain limits in EN 301 489-17. Spurious measurements typically extend up to 12.75 GHz for 2.4 GHz equipment. 09 Compile the test report per EN 300 328 Annex A. The report must include: DUT description, test setup diagram, measurement results with uncertainty, assessment against each clause, and a clear pass/fail statement per obligation category. 10 Issue the RED Article 10(9) Declaration of Conformity (DoC) referencing EN 300 328 V2.2.2 (2019-07) as the harmonised standard applied. The DoC must identify the manufacturer, product, and the two RED essential requirements demonstrated. ## Frequently asked questions ### What's the duty cycle limit under EN 300 328 and how is it measured? The duty cycle limit is 10% per channel over any 1-second observation window. The measurement uses a sliding 1-second window — not fixed 1-second intervals — to find the worst-case transmitter on-time. The DUT is operated at maximum throughput in the worst-case operational mode. On-time is measured using a signal analyser or power meter with time-domain capability. The aggregate duty cycle across all channels cannot exceed 100%. Products that fail duty cycle testing can alternatively demonstrate AFA compliance to be exempt from the duty cycle restriction. ### Does EN 300 328 cover both Wi-Fi and Bluetooth, or do they need separate testing? EN 300 328 V2.2.2 covers both Wi-Fi (IEEE 802.11b/g/n/ac/ax in the 2.4 GHz band) and Bluetooth (Classic BR/EDR and Bluetooth LE). Both are classified as wideband data transmission equipment in the 2400–2483.5 MHz band. A dual-mode Wi-Fi/Bluetooth product is tested under a single EN 300 328 test plan, though the test must cover worst-case configurations for each radio technology. Bluetooth frequency hopping inherently provides AFA-like behaviour, but must still be formally demonstrated against the AFA test requirements in the standard. ### What does AFA (Adaptive Frequency Agility) mean and do I need to implement it? AFA means the equipment can monitor the 2.4 GHz channels for occupancy by other users and adaptively change its operating channel to avoid congestion. Under EN 300 328, implementing AFA is not mandatory — the duty cycle mechanism (≤10% per channel per second) is the alternative. However, modern Wi-Fi 4/5/6 products operating at high throughput almost always exceed the 10% duty cycle limit, making AFA the practical path for any product that transmits significant data volumes. If a product implements AFA, it must pass the AFA test sequence defined in the standard's annexes. ### When does changing an antenna require re-testing under EN 300 328? Any antenna change that could increase e.i.r.p or affect the spurious emission profile requires re-testing. Specifically: switching from an omni-directional to a directional antenna with higher gain, increasing antenna gain beyond the 6 dB directional antenna limit, or changing antenna type in a way that affects the radiation pattern or impedance match. Swapping to an antenna with lower gain or equivalent characteristics may not require a full re-test, but a technical assessment must be documented. The manufacturer must evaluate whether the change affects compliance with each clause and record that evaluation in the technical file. **Disclaimer:** Educational resource only. Regulatory requirements change. Consult a qualified compliance specialist before making decisions. 🇪🇺 CE Marking roadmap for radio equipment Every standard, document, and test that applies — free, no account required. See your free roadmap Learn this properly In-depth course that teaches the full process, not just this one answer. [Start the course — $149](/courses/01-ce-marking-for-electronics-engineers)[Prefer to read? 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