Antenna materials

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AronDouglas

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What are the "acceptable" materials to use when making an antenna? Copper and aluminum are commonly used because of their availability and ease to work with (I think). What about brass or various types of steels? I'd much rather work with steel because it is easier to tap/die threads onto and it is much stronger/rigid.
 

LtDoc

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The first requirement is that it has to be electrically conductive. Then it's a matter of availability, suitability, and ease of use. If you are comfortable in using steel then it's a viable antenna material. Same for aluminum, copper, brass or any other electrical conductor in almost any form.
- 'Doc
 

majoco

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With respect to velocity, don't forget to factor the conductors velocity in to you equation.
Explanation please.

Coaxial cable and other feeders have a velocity factor due to the lumped constants of a transmission line. Bare metal?
 

AronDouglas

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With respect to velocity, don't forget to factor the conductors velocity in to you equation.
Basically..I have a LOT of reading to do :)


Steel is going to rust. You are better off with aluminum.
True but aluminum will corrode as will copper. I will just apply a thin coat of clear coat paint to any antenna I build just to be safe.
 

LtDoc

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Velocity factor can have a little to do with building an antenna, but not much really. The only time velocity factor comes into play is when there's a critical reason for timing or specific lengths for various reasons. With antennas their length mainly determines resonance, which can only be calculated by equations to a 'ball-park' estimate, never exact. From that point you 'trim' that antenna for best resonance then match it to the feed line. Resonance does NOT have to be anywhere close to any particular resistance value. Impedance matching (SWR) takes care of that part of it. They are two completely separate thingys.
For antennas made from wire or small tubing, the commonly found 'magic' numbers (234 and 468) will certainly take care of that velocity factor thingy. (Wire typically has a VF of about 95%. That's where those two 'magic' numbers come from they are respectively about 95% of those other numbers, 246 and 492.)
- 'Doc
 
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