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* No need for extra feed line choke as it is built into the 4:1 balun enclosure
After many requests we have created a compact, special balun for OCF and loop (Skyloop or Delta loop)
antennas. The CB-4-1500OCF is a CUBE enclosure containing a multi-core, broadband 4:1 impedance
transformer in series with a 1:1 current balun for extra common mode current choking to keep RF
current off the outside of the coax braid and on the antenna where it belongs. The extra choking action
also means that the coax feed line will not act as a radiator causing unnecessary RF interference (RFI).
Rated for full 1500 watts PEP and 450 watts CW (ICAS). 1.8Mhz – 31 MHz. 5KW model is 5KW PEP,
1500 watts CW/RTTY/FT8.
Typical size id 1005/F(MHz) and cut for lowest frequency in band segment.
Installation
For best results support antenna at least 30+ feet – the higher the better radiation. Any length of 50 ohm
feed line ok but longer feed lines over 50 feet may show reduced SWR on some bands due to losses in
feed line and soil conductivity, nearby objects, etc. Due to local ground conditions, antenna height and
feed line length, SWR may vary and an antenna tuner may be required or some bands to bring SWR at
end of feed line to acceptable levels. Use a good quality 52 ohm cable adequate for the power level of
your station. The CB-4-1-1500 balun is rated for 1500 watts PEP at 50% duty cycle for RTTY, AM, or
other continuous modes. The 5KW version is rated for full legal limit of 1500 watts for RTTY/FT8
(Model # CB-4-1-5000EB)
