Model 1213 - 1:2 Balun (25 to 50 ohms) 3kW

Maximum Purchase:
2 units
Calculated at Checkout
  • Model 1213 - 1:2 Balun (25 to 50 ohms)  3kW
  • Model 1213 - 1:2 Balun (25 to 50 ohms)  3kW
  • Model 1213 - 1:2 Balun (25 to 50 ohms)  3kW
Frequently bought together:


This is a unique design by Dr. Jerry Sevick (W2FMI) that combines a 25 ohm balun with a 1:2 unun for final transformation to 50 ohms. Used anywhere there is a need to transform 25 ohms balanced to 50 ohms unbalanced. We have eliminated a common failure point of this design by inserting one of the unun windings in Teflon tubing. Consequently this is an enhanced version of the balun used for the popular SteppIR yagis.  IMPORTANT NOTE - This balun is a complex custom wind which requires hand made low impedance, high power coax.   As such this balun is not eligible for exchange or refund except for defect in materials or workmanship.

 This model is also available without an enclosure for use as a replacement for a damaged SteppIR balun. Select model 1213x from above. 


  Core Material   Custom mix low permeability ferrite by Fair Rite Products for maximum bandwidth.
   Large 2.4 inch core is coated and sealed for long term durability.
  Winding Type   Two stage balun/unun wound on single core.
  Winding Material   Hand made 25 ohm impedance coax for first stage balun.
  Second stage is trifilar wound unun of heavy gauge thermaleze wire.
  Center conductor of unun is inserted in Teflon tube to increase cross conductor isolation. 
  7000v breakdown voltage
  Power Rating   1.5 to 31 MHz - 3kW  
  All ratings based on resonant load. High SWR will reduce power handling ability.
  Useable Frequency   1.5 to 31 MHz
  Insertion Loss   Less than 0.3db

  SO-239 connectors are gold center conductor with Teflon insulation.
  Studs and eyebolts are 1/4 inch.
  Alternate connectors and Mounting Options are available in the Accessories section.

  Hardware   All Stainless Steel
  Studs are 1/4 inch
  Enclosure Type
  NEMA rated 4x marine grade junction box for outdoor installations.
  Cover utilizes integral neoprene gasket for weatherproof integrity.
 Dimensions  4x4x2 inches for main body of unit
 Dimensional Drawing of Standard Enclosure
 Additional Info  Very high efficiency (98+%)

Installation Notes


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