diameter of dipole antenna

i am facing problem or choosing the diameter of dipole antenna?

can anybody help in choosing the diameter of dipole antenna?

plz help

What you mean by diameter of wire for antenna (dipol)?
For VHF i use 7 mm for aluminum tube.
For UHF you can use 3 or 2,5 mm aluminum or coper wire
eventualy 4 mm aluminium tube.

i hope that help..

Added after 7 minutes:

Or if you mean how calculate length of dipol:

length = 142.5/f(MHz)

pol_length=length/2 in meters.


----------------------------o o--------------------------------------------

<--------------------- length ------------------------------------------->

<-----------L=lamda/2------------>
============ =========

d be the diameter,
there is specific equation to find length of dipole,as given above?

wat about diameter of this?
how did u choose those values for VHF etc

is there any specific equation for that?

../imgqa/eboard/Antenna/rf-k4v2mbei35i.gif link for figure

Sorry men i just can't find .
I serch trough the internet and nothing.
I must find something in my home books and then i will
made simple program for calculation.
I will present them here...

The larger the diameter, the slower the reactive part of the input impedance changes.

Here is a graph:

following on from that ..... that has the effect of broadening the bandwidth of the
antenna. Which for some applications is very beneficial eg.
on our amateur radio 70cm (430-440MHz) band the repeater input and output
frequencies are 5MHz apart and on the 23cm (1296MHz) Band they are 20MHz
apart. so having a broadened band antenna by increasing the element diameter
ensures tuning is good across the frequencies being used

Dave
VK2TDN

First this jpg image is almost imposibile to read.
Flatulent probably mean on spreading current across dipol element which really
depend of diametar size.
Im very close to solution how calculete proper diametar and i will soon release
windows GUI program which can calculate diametar.
Main thing is in vawe length which is from my current calculation near to Lambda/32.
stay tuned....

hy its good to release

Hi ...
I can't belive that i cannot find any formula on the internet about how calculate
diametar of antenna dipol-weird.
i serch trough 50 pages but nothing concrete,i download few programs but still
nothing.
But must be somwhere ....
So when i find i will make program like i say---

The graph I provided above was made about 50 years ago by empirical measurements. It is from the first edition of the famous Jasik antenna handbook.

No problem i see that image is old.
Here is screenshot of current state of my program
program is on development and is not finished,for antenna calc:

The general rule of thumb, is that the thicker the wire, the wider the bandwidth. However, you can refer to pages 4-4 to 4-11 of Antenna Engineering Handbook, by John Volakis; which I encourage you all to buy, but you can also read online in google books:
http://books.google.ca/books?id=tmNc...ed=0CAcQ6AEwAA

Namely, this is the input impedance:
Zi=R(kl)-j{120[Ln(l/a)-1]Cot(kl)-X(kl)}
where, Zi: input impedance, Ohms, of a center-driven cylindrical antenna of total length 2l and of radius a
kl=2pi(l/lambda):electrical length, corresponding to l measured in radians
and:
R(kl)=-0.4787+7.3246kl+0.3963(kl)^2+15.6131(kl)^3
X(kl)=-0.4456+17.0082kl-8.6793(kl)^2+9.6031(kl)^3