Balun Hybrids include an impedance balun (2:1, 4:1, 6:1, 9:1, 16:1, etc) and a 1:1 balun (choke) in a single enclosure. Use on OCF, loop, terminated dipoles and similar coax fed antennas requiring an impedance transformer Suppresses common mode current on the coax outer braid (prevents your dipole from acting as a tripole!).
Use for 1/2″ Cable – RG8, RG213, LMR-400, AC/DC and signal cable for suppression of common mode current (RFI) from 100 KHz to 30 MHz
Typical common mode suppression up to 22 dB depending upon the number of beads and frequency. Quite often 20 dB is considered the minimum effective reduction.
A minimum impedance of 500 ohms is needed for 50 ohm cable or 10 times the cable impedance for other cables to make a measurable difference in common mode current suppression.
The beads clamp to the cable and may be operated as is for indoor use. However, it is strongly suggested that they be covered to protect the plastic covers from weathering – use electrical tape for best results or heat shrink to ensure longer life. All kits come with instruction manual which covers assembly and application tips.
As you can see from the impedance vs frequency graph, you can very effectively increase the choking impedance by increasing the number of beads on the cable.
Snap On and Slip on Feed line chokes available in sizes to fix cables with outside diameters of 1/4", 3/8", 1/2", 3/4", 1" - check website for other size options.
Tech note: For RFI frequencies over 3.75 MHz, choose SNO31-1/2-5, 10 or 15 for improved common mode rejection (see graph for comparison)