What is an off center fed dipole?
What is an off center fed dipole?
WHAT IS AN OFF-CENTER-FED DIPOLE ? . Whereas a Dipole is a half-wavelength long radiator, fed in the Center of two equal length legs, the Off-Center-Fed Dipole (which I prefer to call a WINDOM) is a Dipole whose feedpoint is at a point removed from the center of the antenna.
How do you make an OCF dipole?
To build the OCF dipole (in this case 80-10m) cut a single length of wire to an overall size of 133′. The 3 additional feet of wire will be used to fine-tune the OCF after you install it. Next, cut the 133′ into two separate lengths of 85′ 2 ½“ and 47′ 9 ½”.
What is an Ocfd antenna?
OCFD stands for Off Center Fed Dipole. This specific antenna is fed away from the center (usually around 1/3 the way). Due to this configuration, the antenna will present good matching on multiple frequencies to allow for multiband operation.
What is a fan dipole?
Full-Size Fan dipoles are multi dipoles that are fed with a common feed point. The full-size dipoles are spread out like a fan, hence the name Fan Dipole. A good example of a Full-Size Fan Dipole is a full-size 40- and a full-size 80-meter dipole on a common feed.
How do you feed a dipole antenna?
Feeding a dipole antenna. Ideally, a half-wave dipole should be fed using a balanced transmission line matching its typical 65–70 Ω input impedance.
Does a fan dipole need a balun?
Yes you do want to install a balun. It’ll keep the RF where you want it – on the dipole legs. The more unbalanced a dipole is the more you need a balun and a dipole in the attic is going to be very unbalanced given the coupling to ducting, wiring etc.
What is the length of a 40 Meter Dipole?
A 40 meter dipole is around 10.10 meters per side. As the fishing poles I had lying around were 8.70 meters this is what I used. Most of the mechanical construction is now ready. Wire length and support. The length of the fishing rods is 8.70 meters and yes, too short.
How do you calculate dipole antenna?
The formula to calculate the length of the antenna is 147/frequency in MHz, this gives the total length of the dipole in metres. For example, to make a 150MHz dipole: 147/150 = 98cm so each element of the dipole should be 49cm.
What is an off center dipole?
Whereas a Dipole is a half-wavelength long radiator, fed in the Center of two equal length legs, the Off-Center-Fed Dipole (which I prefer to call a WINDOM) is a Dipole whose feedpoint is at a point removed from the center of the antenna.