Australian made Radio Direction Finder is exceeding expectations

Mellori Solutions, sister company to Resilience Logistic Solutions, has been busy designing and manufacturing a Radio Direction Finder that allows for detection and location of emergency distress beacons. The Mellori Radio Direction Finder (MRDF) is designed to detect and pinpoint the direction of Emergency Position Indicating Radio Beacons (EPIRB) at a range greater than 30km, maximising the probability of quick location. Low power design gives more than 10 hours of continuous operation for situations where extended deployments are required.

The MRDF is a lightweight, field portable, purpose built, handheld direction finding unit fitted with dual frequency detection (121.5MHz & 243MHz) specifically for the purpose of locating EPIRBs. The unit exceeded the requirement specifications offering simpler operation, lower weight, longer battery life and a line-of-sight detection range in excess of 32km. The sensitive receiver gives a single unit the potential to cover an area greater than 3200km2

When an EPRIB is activated, it transmits a distress signal at a particular standard frequency which passing planes and emergency services monitor. Relevant authorities are notified of activity in this frequency band and will deploy teams to the approximate location of the reported signal to investigate.

The MRDF uses a directional antenna which receives the highest signal strength when pointed directly at the signal source. By sweeping the antenna through 360 degrees it is possible to determine the direction of the transmitted signal. The beacon can be located by triangulation with regular direction checks performed whilst moving closer to the beacon.

The unit emits a tone proportional to the received signal strength whereby the higher the received signal, the higher the pitch. Since the human ear is very sensitive to small changes in pitch, it is quick and easy to locate the beacon by sweeping the antenna and listening for the highest pitch to determine the correct bearing. To guarantee the user is locked on to the correct signal it is also possible to listen to the actual emergency siren chirp the beacon emits.

The MRDF is designed for easy setup and use thus reducing the operator training requirements. The intuitive user interface gives clear and simple feedback allowing the operator to quickly and effectively locate the emergency beacon transmissions.

Related Articles

Our products and services

Resilience Logistic Solution (RLS) was established to focus on meeting the deployable logistic requirements of emergency response, humanitarian and commercial operations. RLS is a manufacturer,

Read More »

What does RLS offer?

RLS creates smarter and safer infrastructure solutions that help field responders perform to the very best of their abilities. Highly robust and endlessly versatile, our

Read More »

Our Values


We achieve excellent outcomes for our partners whether they are agencies, communities or companies; through the provision of excellent products and services and by always doing everything in the best possible way.


Whilst we work with our client partners to provide the right response to meet their needs, we also work with commercial partners to develop innovative and excellent solutions. Our people work in partnership to deliver the best outcomes.


Our products and services support an essential emergency response and sustainment mission. Therefore, our partners must have confidence in our products, services and people. Our people always exhibit integrity; with our partners, and each other, ensuring trust and excellence, every day.


We are committed to delivering the right response to meet our partners’ requirements. We are committed to quality outcomes. Our people are committed to supporting each other.