Hybrid 4:1 Balun + 1:1 Current Balun in one enclosure, 1.8-61 MHz, 1.5/5KW PEP - Loop, OCF AntennasProduct DetailsMPN: CB-4-1-1500TS/EB , CB-4-1-5000TS/EBCountry/Region of Manufacture: USAInput ohms/Output ohms: 50 in/200 outFrequency Range < 2:1 SWR (MHz): 1.8-61 MHz for 1.5KWPEP Power Rating (watts): 1.5KW/5KWInput Connector: UHF SO-239Output Connector(s): Side Eyeboplts (EB) or Top Studs (TS)Enclosure Size: 4"x4"x 2"(1.5KW), 4"x 4" x 4"(5KW)Weight (pounds): 2# (1.5KW), 4# (5KW)Antenna Compatability: OCF, Loop, BBTD, T2FD, ZEPP
After many requests we have created a compact, special balun for Off Center Fed (OCF) , loop (Skyloop or Delta loop) , BBTD, T2FD, folded dipoles antennas. The CB-4-1-1500 is a CUBE(TM) 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 1000 watts CW (ICAS). 1.8Mhz – 61 MHz.
CB-4-1-1500 is housed in a 4” x 4” x 2” waterproof housing with SO-239 input and stainless steel eye bolts on the side for ease of connection to your wire antenna. Top eye bolt acts as an antenna hoist.
5KW are in 4" x 4" x 4" enclosure. 1.5KW is 2 pounds, 5KW is 4 pounds.
For an 80 meter OCF antennas we recommend a (95 feet/79.5% and 40 feet/29.5% offset for best all band results. If you use 66%/34% offset, do not use on 15 meters as the impedance mismatch may damage the balun at high power levels. Loop antennas should be cut for 1005/F(MHz) in total length, where F (MHz) is the lowest frequency to be used. For 3.5MHz this equates to 288 feet.
We highly recommend a feed line choke (MC-1-3000) or coax noise filter (CMNF-1500) at the radio end of the coax feed line to reduce common mode noise picked up by the coax braid.
CB-4-1-5000EB/TS are custom made to order - please allow 7-10 days ARO before ship.
Customer testimonial:
Callsign: NE5U Your CB-4-1500 +1:1 Choke made my homebrew, hail mary, 3 times folded 75m resonant attic dipole into a functional antenna from 6m to 160m. Most bands I can operate with no RFI. I've installed ferrites at all of the usual locations but still have some problem bands. Considering that the antenna is, at best, an NVIS antenna, I have made a lot of DX contacts (SSB, FT8 and other digital modes, and CW). Happy customer here. 73
HF 1-61 MHz coax feed line common mode chokes
After many requests we have created a compact, special balun for Off Center Fed (OCF) , loop (Skyloop or Delta loop) , BBTD, T2FD, folded dipoles antennas. The CB-4-1-1500 is a CUBE(TM) 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 1000 watts CW (ICAS). 1.8Mhz – 61 MHz.
CB-4-1-1500 is housed in a 4” x 4” x 2” waterproof housing with SO-239 input and stainless steel eye bolts on the side for ease of connection to your wire antenna. Top eye bolt acts as an antenna hoist.
5KW are in 4" x 4" x 4" enclosure. 1.5KW is 2 pounds, 5KW is 4 pounds.
For an 80 meter OCF antennas we recommend a (95 feet/79.5% and 40 feet/29.5% offset for best all band results. If you use 66%/34% offset, do not use on 15 meters as the impedance mismatch may damage the balun at high power levels. Loop antennas should be cut for 1005/F(MHz) in total length, where F (MHz) is the lowest frequency to be used. For 3.5MHz this equates to 288 feet.
We highly recommend a feed line choke (MC-1-3000) or coax noise filter (CMNF-1500) at the radio end of the coax feed line to reduce common mode noise picked up by the coax braid.
CB-4-1-5000EB/TS are custom made to order - please allow 7-10 days ARO before ship.
Customer testimonial:
Callsign: NE5U Your CB-4-1500 +1:1 Choke made my homebrew, hail mary, 3 times folded 75m resonant attic dipole into a functional antenna from 6m to 160m. Most bands I can operate with no RFI. I've installed ferrites at all of the usual locations but still have some problem bands. Considering that the antenna is, at best, an NVIS antenna, I have made a lot of DX contacts (SSB, FT8 and other digital modes, and CW). Happy customer here. 73
1:1 feed line Chokes (also known as feed line current chokes, common mode chokes, line isolators, current mode chokes, and 1:1 baluns/ununs) are available in kit form or assembled form in a weatherproof Current Unun and Balun Enclosure which we call a CUBE™. All 1:1 chokes are ferrite based and are designed for 50 ohm coaxial cable input and 50 ohm output. 1:1 Ferrite toroidal or bead chokes have a higher choking impedance than our popular Sleeve Chokes and various models are available for specific frequency ranges and power levels.
1:1 Chokes are useful for choking common mode currents that may flow on the exterior of the coax cable shield while allowing the signals on the interior of the shield and the center conductor to flow unaffected and keeping the common mode current on the antenna. They isolate the coax shield and prevent it from becoming part of the antenna system.
1:1 Chokes are useful between balanced lines for center fed dipoles at their fundamental frequency (468/f (MHz), beam antennas with a 50 ohm balanced driven element, G5RV, loops, yagis, NVIS antennas, mobile installations, portable antennas and anywhere common mode current (or RFI) is a problem. They are also helpful between transmitter and linear amplifier or between linear amp and antenna tuner or as isolation chokes where higher choking impedance is needed (in the range of 2K-7K ohms).
1:1 Chokes are also very useful as feed line current chokes at the “radio end” of the antenna (we call them coax noise filters) where they choke/filter common mode current induced onto the coax shield from radiated waves (from your antenna, and other sources such as DSL routers, computer devices, plasma TVs, etc. originating in your house or your neighbor’s house). For RFI issues see RFI/EMI Solutions for general use or for specific radios and devices.
For best results we recommend a 1:1 choke at the “antenna end” of the coax and a coax noise filter at the “radio end” of the coax. (A side benefit is a reduction in noise level caused by common mode currents). 1:1 chokes are also available as Sleeve Chokes (Slip on or Snap on) for ease of installation and light weight on the antenna.