On Saturday, December 5, 2020 at 8:11:17 PM UTC-6, Matt Herron Jr. wrote:
I have a carbon fuselage, and am considering experimenting with a monopole antenna on each side of the canopy. What I am hoping for is the thinnest wire that will work, taped to the inner canopy wall with clear tape on each side. Hopefully this would provide diversity without FOV obstruction. Can any RF engineer out there suggest length of wire, minimum dia. of wire, etc.. that might work? Advice on avoiding nodal interference patterns welcome as well.

Thanks,

Matt
Matt,

To do what you are trying to do correctly and well is very complicated. To do it right you would need a network analyzer to ensure that at the operating frequency that the antenna has the correct impedance, otherwise you are likely to get seriously degraded range. (Strictly speaking, unless you are properly licensed by the FCC (in USA) you are not allowed to mess with an antenna like this as it could invalidate the RF certifications of the FLARM and conceivably interfere with other services.)

The wire diameter has only second order effect on antenna performance, so mechanical considerations are probably more important. Good conductivity on the surface of the wire is good, and larger diameter helps as well, to a point. 20 to 22AWG solid copper is probably appropriate. The main thing is that the wire length be about 1/4 wavelength at the frequency used. There are antenna calculators on the web that you can use to get a first guess. After that, carefully verify the range before trusting that your FLARM is working like you think (or hope).

Rich L.