According to IACS, 2024 aluminum has basically 1/2 the electrical conductivity of copper. In dealing with these small numbers for Part 15 antenna systems, I would say it would make a difference.
According to IACS, 2024 aluminum has basically 1/2 the electrical conductivity of copper. In dealing with these small numbers for Part 15 antenna systems, I would say it would make a difference.
But I don't have access to copper mesh locally, only aluminum. Therefore, since I would have to order more copper mesh than I want to use, I'm kinda stuck with aluminum mesh which I can cut to size locally, for my cage monopole experiment.
How much overall difference will it make in, say, covering a 8" dia. PVC pipe with aluminum mesh as opposed to copper mesh?
Every bit of resistance counts but in a typical AM situation the coil and ground resistance dominates over the radiator resistance.
I know your situation being by the sea differs from typical but usually the coil and ground resistance total to 20 or 30 ohms. Increasing the radiator resistance from 1 ohm (just a guess) with copper to 2 ohms with aluminum would increase the total from 21 to 22 ohms for example, a 5% increase.
Neil
Since RF travels mostly on the surface of a conductor I would think the resistance of aluminum vrs copper not quite so significant. Maybe a copper clad steel mesh would be less expensive and have the qualities of solid copper mesh where RF is concerned.
Aluminum and steel is certaninly used for the majority of antennas. Do I feel another experiment coming up?
Thanks for the help and advice ...
Only thing I could find about copper-clad steel mesh on the internet was a minimum order of 100 Sq, Meters @ $15/sq.meter.
Tough finding a source for the material for less quantities, so hopefully local aluminum hardware cloth will work.
Skin effect is basically what cage monopoles are about, but most I've seen in the horizontal sets have 4-6 copper wires held by circular disks which act as spacers, the skin effect being emulated by the multiple wires ... except for the near-ground-mounted squirrel cage ones, which is 'sort-of' how my idea will work.
IOW, kinda like a squirrel cage, except the mesh wrapped around the top 10' of a 20' x 8" dia. PVC pipe. 1/4 wave make-up loading coil just below the mesh, TX, ATU, and Ground sealed inside below that.