# How to calculate the optimal diameter of an antenna ?

Discussion in 'General Off-Topic Chat' started by Alkéryn, Dec 11, 2016.

# How to calculate the optimal diameter of an antenna ?

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1. ### AlkérynMoon Dweller ~

Member
7
Mar 15, 2015
Albategnius, Moon
So i need to build an antenna for 433mhz frequency
I know the optimal size is 69 cm (3*10^8/ 4.33*10^6 )^^
but how to determine the optimal diameter (and shape)
plus if i fold this copper antenna into a helicoidal form for it to take less space is it the same size
and finally if I fold it into a spiral is there an optimal "squeeze" for the spiral or not ?

Last edited by Alkéryn, Dec 11, 2016
2. ### FAST6191Techromancer

Reporter
19
Nov 21, 2005
Aerial design/RF design is a strange thing indeed. I don't know how many people here will be familiar enough with it to say what goes, it is something a bit hazy on.
What you will be asked though is are you intending to put out or pick up any kind of distance or directional transmissions? Do you need low level (though many imagine it in a big ball going around the aerial it can be rather different in reality, flattened beach ball being the result of some things)? Are you able to easily move it - if it is on a table beside you and you can just poke it, if it is attached to the roof of your house that may be more troubling?

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3. ### AlkérynMoon Dweller ~

Member
7
Mar 15, 2015
Albategnius, Moon
Actually the antenna i wanna build have to be compact (size of a phone) and a wide enough range (25/50 m)
but the thing is i don't have to make the best antenna to achieve it I'm just verry curious and i would like to know the math behind it
I already know it's lenght have to be the same than the wavelenght or a multiple of it
though I still don't know if it count if i fold it ^^

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