Our MOST ECONOMICAL 1/2" Snap On Ferrite Bulk Pack
Model CB5022-1500 has a balanced output (balun) for matching 50 ohm coax to 22 ohm balanced load at RF power levels up to 1,500 watts PEP when used with a matched load. This assembled balun features a quad core configuration for increased power handling and flatter frequency response to 31 Mhz. With a matched 20-25 ohm load the SWR over the frequency range 1.8 to 31 MHz is less than 1.5:1. The balun is typically used for matching beam antennas with a 20-30 ohm load (direct feed). Mount the weatherproof box on the beam boom with nylon ties and connect a feed line choke (such as the BA-8, or CB-1-1500 or similar) in series between the CB-5022-1500 and the transmitter to prevent feed line radiation.
Impedance transformation over frequency range 1-31 MHz:
CB-5022-1500 is in a NEMA 4x4x2 weatherproof box with mounting flanges at bottom to attach to fixed location (mast, wall, etc). Output terminations are top studs/wingnuts with a SO-239 input for coax connection.
Use a coax noise filter to reduce noise from any vertical antenna or a line isolator to prevent the coax from becoming part of the antenna.