B1-5K & B1-5K Plus

The B1-4K Ultra is the high isolation version of the B1-5K. The B1-5K and B1-5K Plus is unexcelled in their specifications. The B1-5K Plus is currently in production.

5 kW, 1:1, Current-Type Balun

Specification	B1-4K Ultra	B1-5K	B1-5K Plus
Balun Type	Wire	Wire	Wire
Ratio:	1:1	1:1	1:1
Operating Bandwidth	160 - 10 m	160 - 10 m	160 - 6 m
Power Loss, dB	Nil	Nil	Nil
Saturation Resistant	Yes	Yes	Yes
Internal Transmission Line Z	50 Ohms	50 Ohms	50 Ohms
Core Type	Ferrite	Ferrite	HF/VHF Ferrite
Power Rating @ 3.5 MHz	4 kW if SWR < 3:1*	5 kW if SWR < 3:1 *	5 kW if SWR < 3:1 *
Output Balance	Excellent	Excellent	Excellent
Load Variation Tolerance	Excellent	Excellent	Excellent
Input connector	SO-239	SO-239	SO-239
Output Connector	Wire	Wire	Wire
Size	2.3" x 8"	2.3" x 8"	2.3" x 8"

* Important: Not rated for AM, RTTY or other high duty-cycle modes. Power rating is for normal SSB and CW duty-cycles only.

Applications: Dipoles, trap dipoles, Inverted- V, Slopers, etc. Any application requiring a 50 ohm balun.

The B1-4K Ultra is similar to the B1-5K but with a much higher isolation factor. As you can see the only compromise in specification is the loss of 6 meter coverage. If you need maximum feedline isolation, the B1-4K Ultra is the choice.

Just Another 'BIG' Balun?

We built the B1-5K balun as part of an antenna project for the Peace Corps in Zaire, Africa. They needed an antenna for a high power, high duty cycle application. Several commercial antenna systems had failed in similar service, so they asked us to build a bullet-proof system. We developed the B1-5K as the heart of that project.

The Ultimate Balun?

The B1-5K is the answer to requests for a precision 160 meter balun. I do not know of another balun with this combination of precision, specifications, high power rating, and construction quality.

The B1-5K's design makes it remarkably saturation resistant. This prevents signal distortion and potential RFI problems that plague common 'Voltage-type' baluns.

The B1-5K is a Current-type balun, and it takes abuse in stride. Even with power overload and load mismatch, the B1-5K survives. Current- baluns like the B1-5K provide better output balance and far better reactance characteristics than 'Voltage-baluns' that require a nearly perfect load.

With the introduction of newly developed ferrites operating in both the HF and VHF regions, it is now possible, with new winding techniques, to build a balun which covers an additional octave of bandwidth. The result is the B1-5K Plus which efficiently covers 160 - 6 meters with excellent performance.