Off Center Fed (OCF) Antennas Snap On - Mix 43 - RFI Range 25-300 MHz Store/Ferrite Core Products/Mix 43/Snap On - Mix 43 - RFI Range 25-300 MHz OCF antennas are very convenient as they will allow multiple bands of operation with a simple wire antenna which is fed off center with a 4:1 OCF Current balun with built in feed line choke,