1115u-u – 1:1 Single Core Isolation Balun, 1.5-54 Mhz, 3kW for MA5B

  • 1:1 Isolation Balun
  • 1.5-54MHz
  • 3kW handling
  • Dual SO-239 connections

Price excl VAT: £108.33
incl VAT: £130.00

1 in stock (can be backordered)


We have updated and modified the design of this unit to allow the use of a common UHF “tee” on the output for the dual feed of the MA5B yagi.  This allow us to build for lower cost and and less time which we can pass along to the buyer.  Windings of Mil Spec coax allows this balun to provide a very high power rating across all HF frequencies, creates windings that have extremely uniform impedance for near perfect transformation and very high choking/isolation impedance.

Purchase of this unit includes the tee adapter


This balun is more than just high power. Tests show SWR is below 1.06 across the entire HF band, transformation is perfectly flat, return loss is typically 60-75 dbmw and choking impedance peaks at over 5k ohms.


This is a speciality wind and due to the custom nature of this unit,  is not eligible for exchange or return unless there is a defect in materials or workmanship.



  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   Single core, coaxial wound 1:1 current balun
  Winding Material   Mil Spec 50 ohm coax rated 19kW @ 1MHz, 9kW @ 10 MHz and 4kW @50MHz.
Silver flashed braid and centre conductor with solid Teflon dielectric.
  Power Rating   1 to 31 MHz – 3kW continuous – 5kW 50% duty cycle,  35 to 54 MHz – 2kW.
All ratings measured into resonant 50 load.
  Useable Frequency   1 to 54 MHz
  Insertion Loss   Less than .02db
  Connectors   SO-239 connectors are gold centre conductor with Teflon insulation.
Alternate connectors and Mounting Options are available in the Accessories section.
  Hardware   All Stainless Steel
  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.
Will not heat up or saturate at like many of the “less expensive” designs.