[Home](/)/[Resources](/resources)/EN 300 328 — Wi-Fi and Bluetooth Radio Testing EURadioRegulation guide # EN 300 328 — Wi-Fi and Bluetooth Radio Testing for CE Marking EN 300 328 is the primary harmonised standard for wideband radio equipment operating in the 2.4 GHz band — covering Wi-Fi (802.11b/g/n/ax) and Bluetooth (Classic and LE). Meeting EN 300 328 satisfies the essential radio spectrum requirements of RED Article 3.2, and testing to this standard is the backbone of CE marking for virtually every connected consumer product sold in the EU. Copy Link[Share on WhatsApp](https://wa.me/?text=https%3A%2F%2Fkrono-labs.com%2Fguides%2Fen-300-328-wifi-bluetooth) At a glance Standard EN 300 328 v2.2.1 Band covered 2400–2483.5 MHz Max EIRP 20 dBm (100 mW) RED article satisfied Article 3.2 Also required EN 301 489 (EMC) ## What EN 300 328 covers and what it doesn't The scope of EN 300 328 is strictly band-defined: it applies to intentional radio transmitters operating in the 2400–2483.5 MHz ISM band using spread spectrum or OFDM modulation. Technologies operating in other bands — even if they are called "Wi-Fi" — require different harmonised standards. Getting the standard selection right before engaging a test lab avoids costly rescoping mid-campaign. ### In Scope — 2.4 GHz Wideband Transmission Systems EN 300 328 covers all wideband data transmission equipment operating in the 2400–2483.5 MHz band using spread spectrum modulation techniques: Frequency Hopping Spread Spectrum (FHSS), Direct Sequence Spread Spectrum (DSSS), and Orthogonal Frequency Division Multiplexing (OFDM). This covers Wi-Fi 802.11b/g/n/ax (Wi-Fi 6) and Bluetooth Classic and Bluetooth Low Energy operating in the 2.4 GHz band. ### Not in Scope — 5 GHz and 6 GHz Wi-Fi Wi-Fi operating in the 5 GHz band (802.11a/n/ac/ax) is covered by EN 301 893, not EN 300 328. Wi-Fi 6E and Wi-Fi 7 operating in the 6 GHz band fall under EN 303 687. A dual-band Wi-Fi/Bluetooth product requires testing to EN 300 328 for 2.4 GHz operation and EN 301 893 for 5 GHz operation — both tests are typically run in a single lab campaign. ### Not in Scope — DECT, Sub-GHz, and Other Technologies DECT cordless telephone systems use EN 301 406. Sub-GHz IoT technologies (LoRa, Sigfox, FSK at 868 MHz) use EN 300 220. UWB falls under EN 302 065. Thread, Zigbee, and Z-Wave operating in 2.4 GHz use the same PHY as Wi-Fi/BT and do fall under EN 300 328. ZigBee 915 MHz (US variant) would use EN 300 220 if deployed in Europe. ### EN 300 328 v2 vs v1 — Bluetooth-Specific Considerations EN 300 328 version 2 (v2.1.1 and later v2.2.1) introduced the adaptive/non-adaptive equipment distinction that significantly affects Bluetooth products. Bluetooth FHSS systems are non-adaptive under the standard's definitions. Bluetooth with adaptive frequency hopping (AFH) enabled may be classified differently depending on implementation. Manufacturers must carefully classify their Bluetooth implementation against the v2.2.1 definitions before selecting the applicable test route. ## Key test requirements EN 300 328 v2.2.1 test requirements fall into three areas: transmitter performance (EIRP, PSD, OOB emissions), channel access behaviour (LBT for adaptive, occupancy for non-adaptive), and receiver performance (blocking). All must be assessed for each radio mode in a multi-radio product. ### Maximum EIRP — 20 dBm (100 mW) The maximum Equivalent Isotropically Radiated Power for equipment operating in the 2400–2483.5 MHz band is 20 dBm (100 mW). This is a conducted or radiated limit depending on the antenna configuration. For products with detachable antennas, the EIRP limit applies to the combination of transmitter output power and antenna gain. Products using directional antennas must demonstrate the EIRP limit is not exceeded in any direction. ### Power Spectral Density Limit In addition to the maximum EIRP limit, the standard specifies a maximum power spectral density of 10 dBm/MHz EIRP. This prevents a product from concentrating all its power in a narrow sub-band to circumvent the intent of the EIRP limit. PSD is measured over any 1 MHz bandwidth within the occupied channel bandwidth. ### Channel Access — Listen Before Talk for Adaptive Equipment Adaptive equipment (equipment that adapts its channel usage based on interference detection) must implement Listen Before Talk (LBT) with an energy detect threshold of -70 dBm or better. The LBT mechanism must ensure that the equipment does not transmit on a channel that is occupied above the threshold. Non-adaptive equipment does not require LBT but is subject to a maximum channel occupancy limit of 10% per channel. ### Out-of-Band Emission Limits Spurious emissions outside the 2400–2483.5 MHz band must comply with the limits in EN 300 328 and the general spurious emission limits in ETSI EN 301 489. Harmonic emissions and intermodulation products must be measured. The standard specifies limits for the 2400–2483.5 MHz band edges and for emissions into adjacent and non-adjacent bands including the 2483.5–2500 MHz band. ### Receiver Blocking Performance EN 300 328 includes receiver blocking requirements to ensure that the radio continues to receive correctly in the presence of strong interfering signals. The blocking test applies an out-of-band interferer at specified levels while the receiver is receiving a minimum sensitivity level wanted signal. Passing this test is required for RED Article 3.1(b) protection requirements. ### Conducted vs Radiated Measurements Transmitter power can be measured conducted (at the antenna port, for products with detachable antennas) or radiated (EIRP, for products with integrated antennas). Products with integrated antennas — most consumer devices — require radiated EIRP measurements in an antenna test range (anechoic chamber or OATS). Conducted measurements require a known antenna gain to derive EIRP. The test method must match the product's antenna configuration. ## EN 300 328 v2.2.1 vs previous versions The v2 series introduced substantive changes that affect product design and test scope compared to v1. Any product previously certified to v1 must be re-assessed to v2.2.1 for current EU compliance. The transition date for v1 was July 2017 — products placed on the market after that date must comply with v2 requirements. ### Adaptive vs Non-Adaptive Equipment Classification The most significant change in EN 300 328 v2 was the introduction of the adaptive/non-adaptive equipment distinction. Adaptive equipment adapts its transmission to avoid occupied channels using interference avoidance techniques. Non-adaptive equipment uses a fixed or pseudo-random channel plan without dynamic interference avoidance. The classification determines which channel access requirements apply: LBT for adaptive, channel occupancy limits for non-adaptive. ### Listen Before Talk (LBT) Requirement Adaptive equipment must implement LBT with an energy detect threshold of -70 dBm. This requirement was introduced in v2 and does not appear in v1 of the standard. Products designed and tested to EN 300 328 v1 (before July 2017 transition date) may not implement LBT. Any product placed on the EU market after the transition date must comply with v2 requirements — retroactive testing to v2 is required for products previously certified to v1 only. ### Sub-band Power Limits EN 300 328 v2.2.1 maintains the 20 dBm EIRP maximum across the full 2400–2483.5 MHz band. The standard does not impose differential sub-band limits within the 2.4 GHz ISM band for Wi-Fi and Bluetooth, unlike some other regional regulations (e.g. certain national restrictions around 2483.5 MHz). Manufacturers targeting the EU market alone can use the full band. ### Current Version Status EN 300 328 v2.2.1 is the current version. It supersedes v2.1.1 and v1.9.1. The version referenced in the Official Journal of the EU for presumption of conformity with RED Article 3.2 should be verified at time of assessment — the harmonised standards list is updated periodically and older versions may be withdrawn from the list. Testing laboratories will apply the current harmonised version. ## Testing process and lab requirements Running an efficient EN 300 328 test campaign requires selecting the right accredited lab, preparing samples correctly, and combining the radio test with the mandatory EN 301 489 EMC for radio equipment tests. Separating these campaigns is a common and avoidable source of delay and additional cost. 01 Accredited test laboratory selection: testing for RED Article 3.2 must be performed by a laboratory accredited to ISO/IEC 17025 for the specific test methods under EN 300 328. EU-recognised accreditation requires the accreditation body to be a member of the European co-operation for Accreditation (EA) — e.g. UKAS (UK, for UKCA), DAkkS (Germany), COFRAC (France), RvA (Netherlands), ACCREDIA (Italy). 02 Antenna test range or shielded room: radiated EIRP and spurious emission measurements require a semi-anechoic chamber or anechoic room meeting the site validation requirements of CISPR 16-1-4. Some measurements can be performed in a shielded room for conducted tests. Full OTA (over-the-air) testing including receiver tests requires a properly calibrated anechoic chamber. 03 Combined EN 300 328 and EN 301 489 test campaigns: EN 301 489 (EMC for radio equipment) tests — conducted emissions, radiated emissions, and immunity — are typically run in the same lab campaign as EN 300 328 radio tests. Running them separately with different labs or at different times increases cost and delays. Request a combined test campaign from your chosen accredited lab. 04 Typical test duration and sample requirements: an EN 300 328 test campaign for a Wi-Fi + Bluetooth combo product typically takes 5–10 working days of lab time, plus scheduling lead time. Most labs require 3–5 pre-production samples representative of the final product. Samples must use final production firmware with all radio features enabled. 05 Module vs system-level testing: if the product uses a pre-certified radio module, testing the module's CE marking under RED covers the radio element for that module's intended use. However, the final product manufacturer must verify that integration has not materially altered the radio performance and must conduct a compliance assessment confirming the module's CE marking remains valid for the integrated application. ## Frequently asked questions ### Do we need to test to EN 300 328 if our module already has its own CE marking? Not always — but you cannot simply rely on the module's CE marking without due diligence. If the module is used within the parameters of its own test report (antenna type, antenna gain, host device configuration, operating mode), the module's RED certification covers the radio element for the final product. However, you must confirm: the integration has not changed the antenna performance (no additional gain, no detuning), the host device does not generate interference that degrades the radio's spurious emission performance, and the module is operated within its documented parameters. If any of these conditions are not met, supplementary testing is required. The final product manufacturer is always responsible for the DoC. ### What is the difference between EN 300 328 and EN 301 893 for 5 GHz Wi-Fi? EN 300 328 covers the 2.4 GHz ISM band (2400–2483.5 MHz) and applies to Wi-Fi 802.11b/g/n/ax operating in that band, and to Bluetooth. EN 301 893 covers the 5 GHz RLAN band (5150–5725 MHz) and applies to Wi-Fi 802.11a/n/ac/ax operating in the 5 GHz band. A dual-band product (2.4 GHz + 5 GHz Wi-Fi) must be tested to both standards. The key difference in technical requirements is that EN 301 893 includes Dynamic Frequency Selection (DFS) and Transmit Power Control (TPC) requirements for the 5250–5725 MHz sub-bands — these are mandatory and require additional testing beyond the basic EIRP and OOB emission tests. ### Does EN 300 328 cover both the 2.4 GHz Wi-Fi and Bluetooth in a combo module? Yes — EN 300 328 applies to both Wi-Fi (2.4 GHz band) and Bluetooth (Classic and LE) since both operate in the 2400–2483.5 MHz band. For a combo module with both technologies, a single EN 300 328 test campaign covers both radios, but all relevant test cases must be performed for each radio mode separately. Wi-Fi and Bluetooth have different modulation characteristics — OFDM for Wi-Fi, GFSK/DPSK for Bluetooth Classic, GFSK for BLE — and each must be assessed for EIRP, PSD, and OOB emissions independently. The lab will switch between modes and apply the relevant test configurations for each. ### How does Listen Before Talk (LBT) affect product design for adaptive equipment? If your product is classified as adaptive equipment under EN 300 328 v2.2.1, LBT must be implemented in hardware or firmware with an energy detect threshold of -70 dBm. For Wi-Fi products using 802.11 CSMA/CA, the standard 802.11 carrier sense mechanism generally satisfies the LBT requirement — this is built into the Wi-Fi chipset and does not require additional design work. For custom FHSS or proprietary spread-spectrum systems classified as adaptive, explicit LBT logic must be designed into the MAC layer. Products that cannot implement LBT must be classified as non-adaptive and comply with the channel occupancy limit (10% per channel) instead — which may constrain achievable data throughput at high channel utilisation. **Disclaimer:** This page is an educational resource only and does not constitute legal or regulatory advice. Applicable test requirements depend on your specific product configuration, radio technology, and intended operating modes. Always confirm current harmonised standard versions in the Official Journal and engage an accredited test laboratory for product-specific test planning. 🇪🇺 CE Marking roadmap for your product Every standard, document, and test that applies — free, no account required. See your free roadmap[ Want an expert to take your product through 🇪🇺 CE Marking compliance for you? One consultant from Krono's compliance team takes your product from requirements to legal sale, with a fixed quote before any work starts. 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