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AeroVironment announced that it received the first international order for its LOCUST High-Energy Laser Counter-Unmanned Aircraft Systems for over $50 million and that it will supply a number of systems with support, which, according to the company, is “an enabling milestone in the international adoption of directed-energy air defence”. LOCUST combines sensors, tracking and laser defeat against group 1-3 Unmanned Aircraft Systems and other airborne targets. It can be implemented in a fixed, palletized, or mobile configuration and integrated with a wide range of available external sensors and command-and control networks.

A single shot with a LOCUST engagement could cost AeroVironment under $10. That alone presents a huge advantage for laser against cheap, widely produced drones, since air-defence missiles could end up costing much more than the drone. Additionally, there are no traditional interceptor reload limitations on laser weapons-though their performance will still vary by availability of power, conditions, range, and visibility and the world order is adopting AeroVironment’s choice in a $464.8 million contract with the U.S. Army for high-energy laser production, and has ordered over $30 million in new investments in their Albuquerque campus facility, in an environment increasingly calling for layered counter-drone defences.

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US defence firm Covenant has unveiled its Anthem, a ground-launched cruise missile capable of carrying a heavy payload with low unit cost high volume manufacturing. The missile is designed to have over 200kg pay load, and the system is designed to complement established long-range weapons such as Tomahawk and JASSM-ER. Anthem utilizes a solid rocket booster during the boost phase, with a heavy fuel jet engine used during cruise. Covenant states the missile underwent more than 200 flights prior to the unveiling; The firm is aiming at a price of between mid- and high-six digits per missile when in full production.

Manufacturing capacity is the focus of the program, and Covenant has opened up a new 105,00-sqft facility in Dallas intended to build up to 5,000 missiles a year, and is planning an equivalently sized, equivalent-capacity facility in Germany along with an Israeli facility planned to build up to 2,000 units a year. It is estimated Covenant has about $150 million in orders and plans to increase production through 2027. The company has chosen a number of rocket-motor manufacturers and pre-signed thousand-unit long-term contracts for jet engines as a remedy for this bottleneck. Its example is indicative of a broader defence industry trend towards low-cost smart weapons built using scalable commercial manufacturing.

The post Covenant Introduces a Mass-Produced Cruise Missile Called Anthem appeared first on ELE Times.

India is developing its directed energy capability through the Defence Research and Development Organization (DRDO). By utilizing SHIELD and the S-band High-Power Microwave Integrated Evaluation System for Lethality and Damage, DRDO has invited Indian industry to build the platform through the Defence Technology Development Funds program. SHIELD is not a usable weapon system, but an evaluation system that should subject electronics to a controlled amount of high-powered microwave energy and determine the extent of disruption, impairment, or damage.

This capability is of obvious interest to countering UAV’s, as each can have its own controller, navigation device, communication link, sensors, processor, etc. Focusing electromagnetic energy could have a catastrophic impact on these, without actually needing to hit each UAV with a bullet or missile; although this can only really ever prove a cheaper, faster response at very large scale against a large, cheaply produced fleet of UAV’s.

The program can also allow engineers to design friendly equipment that is safe from electromagnetic attack. Test data can lead to the creation of hardened enclosures, shielded cables and connectors, and reliable electronics power sources and ground components. Working with start-up firms and small, medium, and large businesses, the SHIELD project can build a strong indigenous Indian base in high-power microwave technology, EM testing, and electronic warfare that provides an essential platform for both offensive anti-drone weapons and protective electronics.

The post The DRDO’s SHIELD Programme Focused on Microwave & Drone-Electronics Testing appeared first on ELE Times.

The DAC (Defence Acquisition Council) of India approved, to the tune of approx. 1.10 lakh crore across the Army, Navy, and Air Force for procurement under their category, where about 98% of the approval would be for the Indian sector to strengthen the Indian Defence Manufacturing sector in this area. All sorts of platforms and electronic devices are approved under the following purchase categories. Army requires CBRN reconnaissance vehicles, high-mobility vehicles, mechanical Mine layers, ALHs, trawl tanks, and the SARVTRA bridge systems.

The council approved Arudhra radars for the Navy; the indigenous marine gas turbine’s design, development, and subsequent procurement would reduce dependence on foreign vendors and give India greater powers in warship production and maintenance. As for the Air Force proposals, they include a Ground-Based Multi-Purpose Jammer which “will counter adversary radars”; the RFID-based Defence Forces Secure Access Card is another feature that “replaces several documents like identity card, permits. The Acceptance of Necessity can be thought of as an initial clearance to procurement and not a signed contract. Yet the entire package spells out a huge opportunity in terms of radar, electronic warfare, RFID, propulsion, aerospace, and special vehicles supply.

The post 1.10 Lakh Crore Indian Defence Technology Pipeline Approved appeared first on ELE Times.

India is now helping Sri Lanka set up an artificial intelligence laboratory for its Army, making cutting-edge digital technologies a key focus of defence ties. The plan was rolled out by Defence Minister Rajnath Sing during his Colombo visit, during which three other pacts related to defence were signed between the two sides. The laboratory’s functions haven’t been specified yet, but this could include analysis of military data, support for surveillance tasks, logistics and resource management, and quicker planning-all critical elements for operations, officials indicated. The move indicates a trend towards leveraging AI as it has become easier for armies to gain a better grasp of the situations and make effective use of intelligence, data collected through sensors or surveillance equipment.

The agreements also include modernization of the L-70 air-defence guns utilized by the Sri Lanka Air Force and cooperation between the National Cadets Corps and the National Defence Colleges of both countries. Furthermore, India also provided spares for the Mk-II radar, some naval parts, and inflatable targets for training purposes. It indicates the extension of India’s regional defence partnership from traditional hardware and training to AI, digital infrastructure, and know-how exchange. Also, it may offer some new space for India’s defence-electronics firms specializing in sensors, secure communication systems, analytic software, and command and control.

The post India Will Open AI Labs for Sri Lankan Army appeared first on ELE Times.

When enclosure size and airflow constraints limit traditional bass‑reflex designs, passive radiators offer a smarter path to deep, controlled low‑frequency performance.

Audio engineers face a persistent challenge—delivering deep bass extension in compact, space‑constrained enclosures without resorting to unwieldy ports that introduce turbulence and design compromises. 

To address this, many have shifted from traditional bass‑reflex systems toward passive radiator (drone cone) topologies, which replace long ports with diaphragm‑based tuning elements that achieve low‑frequency response more efficiently.

This post will explore the mechanics of passive radiators, weigh their trade‑offs, and outline how to select the right approach for your next build.

How passive radiators work

At the heart of any passive radiator system lies the active driver, the true motor of the enclosure, converting amplifier power into acoustic energy. Its displacement dictates how much air is moved inside the box, setting the stage for low‑frequency behaviour.

Opposite to it sits the passive radiator—the drone cone—which visually resembles a standard loudspeaker but omits the voice coil and magnet. Instead, it functions as a mass‑loaded resonator: the trapped air volume inside the enclosure acts like a spring, driving the radiator in sympathy with the active driver’s motion to extend bass response without the turbulence of long ports.

Passive radiator vs. ported designs

When engineers weigh passive radiators against traditional bass‑reflex ports, the trade‑offs become clear. Passive radiators enable more compact enclosures by eliminating the need for long, tuned ports, and they completely sidestep the issue of turbulent airflow and audible chuffing at high excursions.

Their response carries a perceptibly steeper roll-off below tuning due to the compliance notch at the radiator’s free-air resonance, demanding careful tuning and mass adjustment to achieve the desired performance. By contrast, ported designs typically require larger internal volume to accommodate the port and maintain smooth airflow, and while they risk turbulence at higher levels, their fourth‑order roll‑off often produces a more gradual, natural decay.

Ports are also simpler to implement, relying on standard tubing or slot dimensions, whereas passive radiators introduce greater design complexity but reward it with noise‑free operation and space efficiency. In practice, when a purpose‑built speaker is paired with a matching passive radiator, its low‑frequency performance can extend nearly an octave deeper—delivering exceptional bass response without the added space or turbulence of a tuned vent.

Figure 1 A comparison of bass roll‑off profiles shows the passive radiator dropping more sharply (~30 dB/octave) below tuning than the ported system (~24 dB/octave). It explain that the radiator’s steeper slope comes from the acoustic notch at free‑air resonance, while both remain 4th‑order high‑pass alignments in theory. Source: Author

Critical design considerations for builders

Designing with passive radiators demands careful attention to tuning and balance. The system’s tuning frequency can be adjusted by adding or subtracting weight from the radiator’s cone, a straightforward but crucial step in aligning low‑frequency response with the enclosure’s goals.

Many builders refine this further by attaching extra mass directly to the cone, a technique that shifts the resonance frequency with precision and allows deeper bass extension without altering cabinet dimensions—though care must be taken to avoid over‑loading the driver and reducing efficiency.

Figure 2 A passive radiator with an easily adjustable mass enables the design of extremely compact speaker systems capable of incredibly low-frequency output. Source: Dayton Audio

Equally important is the volume compliance ratio (δ), where the passive radiator’s displacement volume should be 1.5 to 2 times greater than that of the active driver, ensuring efficient energy transfer and preventing the radiator from bottoming out. Finally, builders often employ dual passive radiators mounted on opposing sides of the cabinet, a technique that cancels mechanical reaction forces and stabilizes the enclosure. This vibration‑cancellation approach has become especially popular in portable Bluetooth speakers, where compact form factors and mechanical stability are paramount.

Chamber considerations

Every passive radiator system relies on the enclosure chamber as the “spring” that drives the radiator. The trapped air volume inside the cabinet provides the restoring force, so the chamber size must be carefully matched to the driver and radiator parameters. Too small a chamber can raise the tuning frequency and limit bass extension, while too large a chamber can reduce control and efficiency.

In practice, builders balance chamber volume against radiator size and mass, ensuring the compliance of the air spring complements the driver’s displacement. This makes chamber design just as critical as cone mass or compliance ratio when aiming for clean, extended low‑frequency performance.

At its core, the passive radiator system is simply another expression of the Helmholtz resonator principle. In a ported design, the mass of air in the port oscillates against the compliance of the chamber air, producing resonance at the tuned frequency.

With a passive radiator, the cone itself replaces the air column, acting as the moving mass while the trapped air in the enclosure remains the spring. This substitution preserves the Helmholtz effect but eliminates turbulent airflow, enabling deeper bass extension in compact cabinets without the drawbacks of long ports (port tubes).

Figure 3 Large-diameter port tubes optimize bass response in the active resonator circuit but increase enclosure volume and introduce air-chuffing distortions that passive radiators inherently avoid. Source: Author

Additional considerations

Beyond the fundamentals, builders should also weigh practical details that shape real‑world performance. Passive radiators generally require greater displacement capacity than the active driver—typically 1.5 to 2 times more—to move sufficient air at low frequencies and avoid bottoming out under load. Excursion limits are equally critical, since radiators can lose control if driven beyond their mechanical capacity.

Designers also watch for unwanted resonance peaks in the mid‑band, often around 1–2 kHz, which can be tamed with damping materials or improved suspension structures. Unlike ports, radiators don’t provide airflow cooling for the driver, so thermal management becomes a factor in high‑power systems. Finally, measurement and simulation tools such as impedance sweeps or modelling software are invaluable for predicting system behavior and ensuring the radiator is properly matched to the enclosure.

Also, accurate parameter testing is vital when integrating passive radiators. What’s more, builders can rely on impedance sweeps, frequency response plots, and excursion measurements to confirm tuning and displacement margins. These tests not only verify that the radiator achieves its intended resonance without bottoming out, but they also expose mid‑band anomalies or thermal limitations. While simulation tools provide useful predictions, hands‑on measurement remains the most reliable way to validate radiator behavior in a real enclosure.

Figure 4 A datasheet snippet outlines the key technical specifications for the passive radiator. Source: PUIaudio

Material choices for passive radiators

The diaphragm material defines how a passive radiator behaves under load. Rubber and elastomer membranes dominate portable designs, offering flexibility, damping, and resistance to moisture. Polymer composites such as ABS or PET provide lightweight stiffness and cost‑effective molding, though they can fatigue under high SPL.

Metal plates—aluminum or steel—deliver precise mass and long‑term stability but add weight and require damping to avoid ringing. Hybrid laminates that combine rubber with metal or fiber composites balance compliance with rigidity, giving engineers a tuneable middle ground. Selecting the right material is ultimately a trade‑off between durability, acoustic control, and the enclosure’s performance goals.

Application matrix

Choosing between a passive radiator and a ported design depends on the priorities of the build. Passive radiators excel in ultra‑compact or battery‑powered Bluetooth speakers, where enclosure space is at a premium and port tubes would be impractically long. They are also favored in subwoofers that demand deep extension without sacrificing internal volume, and in applications where eliminating port turbulence or chuffing is critical.

Ported designs, on the other hand, remain the go‑to for high‑power, high‑SPL systems such as PA speakers, as well as budget‑focused projects where standardized tubing makes tuning straightforward. When enclosure size is not a limiting factor, ports offer a simple, effective solution with predictable performance.

Passive radiators and ported bass‑reflex designs each bring their own strengths to the table—radiators deliver compactness, vibration control, and noise‑free operation, while ports offer simplicity, predictable tuning, and gradual roll‑off at the expense of larger enclosures and potential turbulence. The decision ultimately rests on your design priorities: whether you value space efficiency and acoustic precision, or raw output and ease of implementation.

As you move forward with your projects, think about which trade‑offs align best with your goals. Are you crafting a portable Bluetooth speaker that demands stability and compactness, or a high‑SPL system where simplicity and sheer output dominate? Share your builds and design choices—I’d love to hear how you’re pushing bass performance beyond the port.

T. K. Hareendran is a self-taught electronics enthusiast with a strong passion for innovative circuit design and hands-on technology. He develops both experimental and practical electronic projects, documenting and sharing his work to support fellow tinkerers and learners. Beyond the workbench, he dedicates time to technical writing and hardware evaluations to contribute meaningfully to the maker community.

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The post Beyond the port: Fundamentals of passive radiators appeared first on EDN.

Heya everyone! I'm Berry a cutesy trans gal! and I created a simple galvanic electrolysis machine from scratch ✨ It runs on a 5V USB power supply (smartphone/power bank/usb brick) , steps up to 30V, and limits current to a safe range (0.13–1.13mA). The total cost of this final interation works out around to roughly less than ₹600 or under $7 Quick specs :3 • Power: 5V USB → XL6009 → 30V • Current range: 0.13–1.13mA (I usually use 0.4–0.6mA) • It uses an LM324 , two 2N2222 , a few resistors, capacitors and two pots! • if built on breadboard then no soldering required Made from really few electronic components ✨ You can check out the whole document about it with the link here https://drive.google.com/drive/folders/1Q0zdHmhQ3L9I2UA0SnqAUSbfd it includes , schematic, parts list, build guide and more!! I also diy-ed the probe holder , and ermm the needle! but that's another thing on itself and not something I would recommend but yeah! I do have a design for a diy probe holder for commercial needles though if anyone is interested in that! If anyone has any questions then feel free to ask them 🫶✨ Edit:- yes i've tried it on myself!! And treated 65+ follicles in my second time using the machine on myself \^\^ r/diyelectrolysis https://cdn.imgchest.com/files/597c77d60eee.jpg [Schematic](https://cdn.imgchest.com/files/3bd2baf37d40.jpg) submitted by /u/BlueberryCultural361 [link] [comments]

Олександр Чорний (05.12.1989 – 13.03.2022) kpi сб, 09/12/2026 - 21:04

💎 Набір до команди «Формула Студент КПІ» kpi сб, 09/12/2026 - 20:49

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CVD Equipment Corp (CVDE) of Central Islip, NY, USA (a designer and maker of chemical vapor deposition, thermal processing, physical vapor transport, gas and chemical delivery control systems, and other equipment and process solutions for developing and manufacturing materials and coatings) has announced a restructuring plan and leadership transition, following a thorough evaluation of strategic alternatives for its CVD equipment business by its board of directors...

Доповідь ректора КПІ ім. Ігоря Сікорського Анатолія Мельниченка на сесії професорсько-викладацького складу 2026 Інформація КП пт, 09/11/2026 - 17:00

Hey guys! I got into electronics and computers during the pandemic, but could not continue it further due to school work (and being a broke 14yo lol). Finally 6 years later I managed to save up and get myself some components to put something together that felt like an actual project. I will be happy to get any feedback! Github link for details submitted by /u/OjasZ [link] [comments]

Reporting the results of its Flight-1 ‘Mission Asimov’, Washington DC-based Besxar (which is developing the manufacturing of advanced semiconductor materials in space) says that, on 5 July, two of its ‘Clipper-class’ canisters flew from Space Launch Complex 40 (SLC-40) at Cape Canaveral Space Force Station in Florida aboard a SpaceX Falcon 9 first-stage booster and were recovered intact after the booster returned to land...