1500 Watt Rated 1.5:1 CUBE™ Unun

Purpose. The CU-1.5-1500 (1500 watts PEP) or CU-1.5-5000 (5KW PEP) is used as a 1:1 unun(aka feed line choke, line isolator) for 50 ohm unbalanced coax cable input to 75 ohm unbalanced coax output at full amateur radio legal power (1500/5000-watts PEP) into a matched load 50 ohm load for 1.8-61 MHz (or a balanced output load for the CB-1.5-1500/5000). The unun (or balun) is designed to have a high RF impedance to common mode currents on the outside of the coax braid while passing RF currents on the inside of the coax braid to the antenna.

For maximum common mode current protection (and receiver noise floor reduction due to common mode current pickup by the coaxial braid), use one feed line choke such as the CU-1-1500 (for 50 ohms coax) or CU-1.5-1500/5000 (for 75 ohm coax) at the antenna and another at the radio shack equipment connection or input of antenna tuner.In some difficult RFI cases, additional common mode chokes are needed between equipment such as linear amps and antenna tuners, and transceivers.

This Unun or Balun designed to work with 75 ohm loads and the Unun/Balun will be damaged if you use at high impedances and high power such as driving a 40 meter antenna with an 80 meter transmitter signal where the load impedance on the antenna is very high.Best use is with antennas having a load impedance near 75 ohm range.