Off Center Fed (OCF) Antennas Mix 75 Store / Mix 75 Ring - Mix 75 RFI Range: 150 Khz-10 MHz Ring - Mix 75 RFI Range: 150 Khz-10 MHz Snap On - Mix 75 - RFI Range 150 KHz-10 MHz Snap On - Mix 75 - RFI Range 150 KHz-10 MHz Slip On - Mix 75 - RFI Range 150 KHz-10 MHz Slip On - Mix 75 - RFI Range 150 KHz-10 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,