Off Center Fed (OCF) Antennas Mix 31 Store / Mix 31 Ring - Mix 31 - RFI Range: 1-300 MHz Ring - Mix 31 - RFI Range: 1-300 MHz Snap On - Mix 31 - RFI Range 1-300 MHz Snap On - Mix 31 - RFI Range 1-300 MHz Slip On - Mix 31 - RFI Range 1-300 MHz Slip On - Mix 31 - RFI Range 1-300 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,