Zener_Diode said:Hey
as much as the freq is low the antena should be longer. l=c/f (c=3*10^8)
if I take a freq of 2Mhz the antena is about 150 meters.
I hear about the option to connect a serial inductor to the antena and then you can choose the antena long you want.
how can I calculate this inductor????
Zener_Diode said:nope, the antena have 2 length. one is a lenght in meters, cm and so on.
and another is electronic length, L(electronic)=l(meter)/0.95.
as I know, you can add a serial inductor to antena that simulate a longer electronic lenght.
and it doesn't metter what is antenas impedance.
Zener_Diode said:In the AM radio 530Khz - 1600Khz. the antena lenght is about(566 - 187.5 meters) did u ever see tuner with antena more then 20cm????
if u ever open the tuner, u saw an inducor coiled on a black material. it's material is s special unmagnetic material that can change its poles very fast. This part in the radio replace the lenght of the antena.
and if it is so... how can I culculate the numbers of coils that I need to wind on the ferrite rod antenna to get an excellent receive??
JimB said:To find how many turns to put on our coil, first consider that putting the coil on the ferrite rod will double the inductance.
So we need an air cored coil of 85uH (half of 169, near enough).
To find the inductance of an air cored coil, we can use:
N = (SQRT(L x (9 x A + 10 x B))/A
Where N is number of turns
A is the radius of the coil in inches
B is the length of the coil in inches
And for 85 uH, radius 0.1875 inch, length 2 inch, I make it 68 turns
Zener_Diode said:OK.
thank you very much.
And to all people that tried to help me.
Zener_Diode said:I am not going to do something. just I heard about that, and wanted to know more detailes. thats all.
In the futer I wanna do a robot that will have a wireless comunication.
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