Today I investigated the shroud mounted antenna which is installed on most CFM Shadows.
Here is a photo of Georges’ antenna. The antenna has been installed for many a year with the hoop as the ground plane. I thought it worked well. I suppose it did its job as most of the installations out there do but little did I know. The difference is the acceptance of the white RF noise as normal but very draining and is something we all put up with. It can be a lot better! A bit like alcohol free beer…..
Measurements taken standing next to the cockpit. Yes this makes a diffrerence!
Sitting in the cockpit with the canopy OPEN.
Sitting in the cockpit with the canopy CLOSED.
Canopy closed and wearing a headset
I spent the whole day messing about with it but sadly could not get any stable results. Just as with the handheld radios, the person is a major contributor to the ground plane.
Bottom line is each configuration will require the pilot to sit in it and tune the aerial accordingly. I’m happy to do this but the real answer is a stable antenna which resonates with its ground plane correctly. The stable antenna will require less battery power and 5x the range AND knock out the white noise of its unstable ground plane!
I’ve got to end with a golden nugget!
**GOLDEN NUGGET** – All wires, rods, airframes etc all are antennas!