I was looking at a design for a helical antenna that suggests brass wire for the helix. Is there a reason that brass would be better than copper for the helix? I am not sure if the gain would suffer that much if I used copper.
Antennas should be build with alluminium, copper has a slight better conductivity but oxidation is an issue. Brass has conductivity of 3.5 to 5 time that of copper, while alluminum just 1.6 worst. So brass is unsuitable. Obviuosly one had to consider that alluminium is quite impossible to solder and cable are made of copper (with some surface deposition) and corrosion can happen due to different metals in contact. It’s not a trivial task to chose the right material for an antenna but brass is definitively not a good choice.
One can argue that in the points where currents are low resistivity is not an issue but an antenna (longer than lambda/4) has point with low current and others with high current…
Hope this help
You mean resistivity, right?
Yes, sure, sorry. I have coductivity table in front of me, I’ve converted in resistivity but I wrote down the wrong term