Holistic Approach Is Beacon For Waterproof Connectors

When a market leading manufacturer of personal locator beacons, PLBs, was faced with a problem when military aircrew were using its beacons, the company called in intelliconnect to help solve the problem. Simply, the problem arose in a non-functioning beacon when crewman had exited the aircraft or boat. But tracking down the problem proved difficult to understand as, like any other piece of emergency equipment, these PLBs were subjected to rigorous testing during manufacture and also a further full functionality shake-down test prior to the manufacturer despatching the equipment.

A thorough investigation of the way the beacons were being used was undertaken, and the problem finally identified by intelliconnect. Prior to the aircrew bailing out of an aircraft, they would be inclined to twiddle with the PLB antenna and in some cases accidentally disconnect it from the beacon. On bailing out, the PLB would then fill with seawater, leaving the crew member wondering why rescue took longer than anticipated. With the PLB full of water its ability to transmit its location was severely limited and in some cases could even cease to operate.



So the challenge was set in providing a mated pair of connectors that would be waterproof to minimum IP68/NEMA 6P ratings for up to 20m immersion for a minimum period of four hours unmated. And as usual with Intelliconnect designs, the company took its usual holistic approach, with the complete system investigated.



To provide a sealed connector, complete with modularity and ease of assembly, a TNC to MCX adaptor was designed by Intelliconnect. This enabled a separate umbilical link to be used inside the equipment which greatly improved the flexibility of the manufacturing process. The mating half needed careful consideration, says the company, as the personal locator beacon had to be used in confined spaces. So a low profile, TNC right angled plug, also sealed to IP68, needed to be developed.

A further part of the design brief required Intelliconnect to take into account the need to attach additional GPS and transmitting antennas without them being connected, inadvertently or otherwise, to the wrong ports. For this requirement, a solution was developed using standard and reverse polarity TNC connector designs that would clearly indicate if attempts were made to wrongly connect them.



The final part of the system to be protected was the battery connector. By using the experience and knowledge gathered on the antenna connector design, it was a relatively simple task to apply this know-how to Intelliconnect’s Nim-Camac connectors and also seal them to achieve the necessary IP68 rating unmated.



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The resultant Intelliconnect solution emerged from the company’s holistic approach to solving the problem, says the company, rather than just addressing the connectors, hence drawing on the company’s vast experience in designing for harsh environments.



The final solution featured a combination of O-rings and proprietary methodology to protect the connector, and thus the PLB, from moisture ingress under seawater at depths down to 20m.

Notably, rigorous testing by Intelliconnect and the PLB manufacturer proved that the new connector design was able to protect the equipment to an equivalent depth of 60m, exceeding the original product requirements and providing the customer with a healthy threefold safety factor.

The standard method employed to test connectors is pressurisation of the connectors using compressed air, followed by immersion in water and subsequently checking for air bubbles as a sign of leakage. This is simple enough to be used as an in process operation and can quickly and easily highlight any process or assembly problems.



In addition to the sealing requirements, the resultant connectors are designed to meet all the relevant Mil specs, durability requirements, electrical, mechanical, and environmental conditions that all standard military equipment needs to withstand to be able operate in an airborne or seaborne environment.



And of course now, Intelliconnect has incorporated this waterproofing process for TNC connectors into many of its other products including the N series, SMA, and custom designs such as the ABMS, an MCX derivative used for a cochlear implant, and the MPNC four way multi-pin connector for environmental corrosion monitoring.



These connectors and adapters now form the market leading “Pisces” range and other applications include traffic monitoring systems, rail traction systems, military and aerospace applications, medical, marine radar, battery power, and corrosion monitoring for the oil and gas industry.

Intelliconnect is a UK manufacturer of RF connectors and cable assemblies, based in Chelmsford and with facilities in the USA. It specialises in the design and manufacture of waterproof connectors, with the capability to design, develop and supply interconnect solutions to customer driven specifications in weeks not months.