1500/5000 Watt 6:1 CUBE Balun™ – Model CB-6-1500/5000

Model CB-6-1500/5000 is a 6:1 (300:50) balun housed in a NEMA enclosure box (1.5KW in 4″ x 4″ x 2″, 5KW in 4" x 4" x 2") with two top studs capable of input power levels up to 1.5KW PEP watts when used with a matched load. The 6:1 ratio takes 50 ohms input and matches to 300 ohms balanced output from 1-61 MHz with SWR < 1.5:1 under matched load conditions. A great balun for windoms, OCF antennas >60 feet over ground, Hertz and folded dipole antennas, T2FD etc. 8 core, Use “EB” version with side eye bolts for wire attachments for OCF dipole use.

Tech Note: 5K version is rated to 31 MHz under 2:1 with matched load.

Typical SWR and impedance transformation from 1-61 MHZ shown below:

This transformer requires a feed line choke to isolate the coax feed line from the antenna. The hybrid CB-6-1-1500 incorporates the 6:1 transformer and the 1:1 choke in the same container. A coax noise filter such as the CMNF-1500 is also recommended at the radio end of the coax to reduce common mode noise.