In this session, Dave provides an overview on how to design solutions for challenging airframe antenna applications. In addition, Dave discussed the nuances of working within the aviation space, and how Times Microwaves’ aircraft applications are designed to work in the challenging conditions that military-grade aircrafts endure on a daily basis. For example, the unique properties of a Times Microwave military/tactical-class feeder antenna lineup is designed to be equal parts durable and repairable for quick fixes on popular military aircraft like the C17.
Watch the video or read the session notes below.
A typical aircraft antenna installation involves a two-port antenna with a TNC female and an N female, a double plate matching the arc of the aircraft, and two cable assemblies. Once mated, the antenna is attached to the aircraft, and the two connectors attach to the antenna. However, this is 1960s technology. Let’s see what we can do about that.
There are standard technical considerations in terms of maintenance and access with an antenna mount located on an aircraft:
To address these concerns more effectively, let’s discuss a blind mating of the same antenna. This involves identical double plate and cable assemblies, but the N and the TNC connectors are replaced with blind mate versions. This eliminates the coupling nut and the lock wire scheme in favor of a captive spring column.
The alignment sleeves are attached to the antenna, one N and one TNC. Once these are mated, it turns into a blind mate-able surface. This stainless-steel alignment sleeve has turn rings, one that seals the threads from the outside in, and another that seals to an interface. To make this mount, the receiver sleeve is put up and then mounted to the doubler plate itself, and based upon the location and the height of the antenna, the zero position of the receiver sleeve is determined. Each of these receiver sleeves has a C-clip on it to hold it in place and the base connector threads directly onto it.
Anytime there is a male, female TNC or a male female, as the connectors mount, they typically wear out at well under 500 mates. Additionally, after 500 mates and de-mates, a lot of metal debris has been generated that has likely filled that interface, resulting in potential electrical issues.
With the blind mate solution, as the nose cone is closed, the four alignment sleeves engage into a bracket that has a slight rotation on it. The springs engage as the nose cone is tightened in place. This type of antenna junction has been tested for wear and tear, resulting in 5,000+ mates with no failures.
This example details an F35-C carrier landing condition with a significantly high vibration profile. On the right-hand nose door, there is a microwave landing system and an integrated carrier landing system. Each antenna contains a connector. In a normal test environment, a Band Aid connector such as a TMA can be attached. This is a three or four prong mated connector that enables antenna testing, antenna patterns, etc.
However, these landing system antennas are located on the inside of the nose door on a low observable aircraft. To find an airport or a ship, that nose door has to be opened—and this happens at up to 300 knots, which is equivalent to about a Class Five hurricane in the internal cavity. The problem with mounting a typical right-angle connector to one of these antennas in that kind of a vibration profile is that they tend to break.
Instead of continuing to mount the antenna the same way, we came up with the idea of using a multiport connector instead. Once the antenna has mated, it gets an environmental seal that engages the amount necessary for tolerancing. However, no motion is generated as a function of the vibration profile—it’s basically all neutralized at the bracket. The result is a very high performing RF interface at 300 knots in the carrier landing environment.
Following are the questions that were asked by the audience:
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