Electronics > RF, Microwave, Ham Radio

Question about making 433MHz antenna


I want to make a 1/4 wave 433MHz antenna. Should I be concerned about the type of wire I use.
I understand that it needs to be 173mm long but is it ok to use silicone insulated stranded copper wire?

Hi yes that will be fine, use the thickest wire will give you the best band width, but at 433mhz it will be wide ,don't forget your counter-poise/ground is half of your antenna, if I was you I would make a halfwave ant and get some gain.
Dave 2E0DMB

To add to that, you want to think about which type of antenna will work better for your application-an omnidirectional or a beam antenna.  The beam will give you gain at the expense of front to back and side to side rejection.  Otherwise, Dave is on the mark with a 1/2 wave or better to get gain.  Gain is good! :-+

Tom, NW0LF

To answer your question about making a 1/4 wave, the type of conductor you use doesn't matter.  One point to note though is that the length you quoted 173mm is the free space wavelength.  It will be slightly shorter in a piece of copper wire, more like 168 / 170mm.  if you are using it for a receiver then it won't really make much difference, but if using it for a transmitter you will need to trim it to resonance either by using an SWR measurement or by trimming for maximum radiated signal.  The ground system you use and the environment will also affect the length slightly.


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