Ads
related to: coiled coax choke balun
Search results
Results From The WOW.Com Content Network
An RF choke can be used in place of a balun. If a coil is made using coaxial cable near to the feed point of a balanced antenna, then the RF current that flows on the outer surface of the coaxial cable can be attenuated. One way of doing this would be to pass the cable through a ferrite toroid.
Homemade 1:1 balun using a ring of ferrite around which the coaxial cable is wrapped. This simple RF choke impedes signals passing on the outside of the braid, which helps to cure television interference. A braid-breaker is a filter that prevents television interference (TVI).
For example, on unbalanced coax transmission lines (such as video cables), the cable is designed to contain the signal, and beads can be used to block stray common mode current from using the cable as an antenna while not interfering with the signal carried inside the cable. In this use, the bead is a simple form of a balun.
A coax balun is a cost-effective method of eliminating feeder radiation but is limited to a narrow set of operating frequencies. One easy way to make a balun is to use a length of coaxial cable equal to half a wavelength. The inner core of the cable is linked at each end to one of the balanced connections for a feeder or dipole.
By winding the coax into a coil around some ferite as depicted, these differeneces are eliminated (or at least greatly reduced) by a choking action thus balancing the signal on one end of the device regardless of what is happening on the other.Euc 12:50, 17 June 2012 (UTC) The choke balun does act as a transmission line transformer.
The name "choke" is used because the equal and opposite (anti-parallel, balanced) currents in the coax or paired wires cancel each others' magnetic fields, allowing them to pass through unhindered, but magnetic field of the unbalanced flow inhibits the unbalanced current, "choking" it off. Similar reasoning applies to the name "line isolator".