who can help me regarding the antenna phasing coil , uses and calculation formula ,please.

Hello Radium!

What antenna are you using??

If you are referring to a Loading coil for End fed antennas? The impedance differs as to where you terminate the feedline? (coax connection) The loading coil therefore acts as an impedance transformer!

Centre fed (dipoles) would be around 50 ohm! Where as end fed can be up to 5000 ohm?

Antenna coils can also just be a type of Balun which serve a different purpose, Generally a length of coax either 1/4 or 1/2 wave wrapped @ your chosen frequency will be sufficient!

Give us a clue as to what frequency band - MF, HF or VHF!

Sorry guys for the long cut period , from the forum , and i would like to say a very merry Christmas for you and everyone who celebrate , this happy end of season , but not here in mine and happy new year in advance .for the up question i am asking pf the matching coil or phasing coil , to earn more gain of the antenna .
pictures are illustrative .the phasing coil is to eliminate the phase and making more gain , but how it is calculated , anyone knew how .