Baluns

This Balun is best for Loops, OCFD Off Center Fed Dipoles, Folded Dipoles and any other antenna that presents a feed point impedance of around 200 Ω.

It covers the entire HF spectrum from 1.8 MHz to 30 MHz, has very low loss of <0.12 dB, handles 1500 watts, and is fully weatherproof.

The Hybrid Balun combines the best of both worlds:  Voltage Baluns and Current Baluns.  It is comprised of a Ruthroff 4:1 Voltage Balun followed by a broadband Common Mode Choke (also known as a Current Balun or Choke Balun).

It matches a ~200 Ω antenna to a 50 ohm coaxial cable feedline AND balances both the voltage and the current in each leg of the antenna. This makes it especially desirable for use with Off Center Fed Dipoles (whether Horizontal or Vertical) which are, by their nature, unbalanced - and tough to balance.    

Because the antenna is matched and balanced: SWR, CMRR, and signal strength are increased while common mode current, RFI and received noise are all reduced.

   * Sealed and can be mounted in any orientation  

   * It can be mounted to a solid surface with screws, or

   * hung by the top eyebolt, or

   * suspended between the side eyebolts, or

   * attached to a mast or boom with U-bolts using one of our Mounting Kits

Because every Ham running a balanced antenna fed with coax needs one to balance the current in both legs of the antenna and stop common mode current.  Baluns also act as broadband impedance transformers and match the coax to the feed point impedance.

Common mode current flows down the outside of the coax shield, distorting your antenna's radiation pattern, increasing RFI into your shack, and raising your receive noise floor.  It is essential to keep common mode current in check with a proper balun and choke.

A balun is a device that interfaces a balanced antenna with an unbalanced coaxial cable feedline. The word "balun" is a contraction of "balanced to unbalanced".  Without a balun, the coaxial cable becomes part of your antenna system in ways you never intended.  A good balun stops that from happening — keeping RF where it belongs and your antenna performing the way it was designed. 

There are two fundamentally different types of baluns, and choosing the wrong one for your antenna is a common and costly mistake. A voltage balun forces equal and opposite voltages on each leg of the antenna — but makes no guarantee about current balance. A current balun, also known as a choke balun, forces equal and opposite currents in each leg of the antenna, which is what actually determines the radiation pattern as well as common mode current suppression. For most ham radio antennas — especially dipoles and yagis with feed point impedances near 50 ohms — a current balun is the correct choice. A voltage balun is often the right choice for loops, off centere fed dipoles (OCFD), and folded dipoles.

The right balun depends on two things: your antenna's feed point impedance and how well balanced it naturally is. A 1:1 current balun is ideal for dipoles, yagis, and other antennas with feed point impedances near 50 Ω. A 4:1 balun provides an impedance match for antennas with feed point impedances near 200 Ω, such as loops, folded dipoles, and off center fed dipoles (OCFDs).  Getting the impedance ratio wrong increases SWR and reduces power transfer to your antenna. 

Off center fed dipoles (OCFD) are inherently unbalanced and that makes them one of the most challenging antenna types to feed correctly.  A standard 4:1 voltage balun will match the impedance, but it does a sub-optimal job of balancing current in each leg of the antenna.  Voltage balance and current balance are not the same thing. The result is elevated common mode current, a distorted radiation pattern, and RFI in your shack and neighborhood.  The cure is to use a Common Mode Choke between the Balun and the coax feedline.  A hybrid balun makes life easier by including a Common Mode Choke inside the Voltage Balun's enclosure.

For OCFD operators, this is not a luxury, it's a necessity. 

Every Watts Engineering Labs balun is built to handle the full HF spectrum from 1.8 to 30 MHz with exceptionally low loss. Our 1:1 Current Balun exhibits less than 0.09 dB of loss — completely undetectable on transmit or receive. Our 4:1 Hybrid Balun adds less than 0.12 dB across the entire HF band. These are not theoretical figures — they are measured values from fully characterized units, built to commercial RF equipment standards. 

Every balun is sealed for outdoor use and can be mounted in any orientation, with multiple mounting options to suit any installation.