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Balun Designs

Model 4132 - 4:1 Unun for Multiband Verticals and Random Wires, 2kW


Model 4132 - 4:1 Unun for Multiband Verticals and Random Wires, 2kW

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Product Description

This is the single core version of our popular 4:1 unun model 4134 designed for use with wire verticals, random length long wires and monopole verticals. Wound on a single core for reduced power applications, this unun delivers efficient broadband performance and good power handling across all HF frequencies. Works well with both internal transceiver and external antenna tuners.  The model 4132u is designed primarily for the Eagle One multiband vertical but can be used anywhere two SO-239 connectors are desired.

This unun is an excellent match for any of the 43 and 31-33 foot multiband verticals including the S9, ZeroFive, MFJ, Eagle One  and DX Engineering vertical antennas allowing the use of moderate to high power.

NOTE: For ground mounted vertical installations, the "s" model (4132s) is strongly recommended. 

Although many customers report very good performance using just a single ground rod, the best performance will come from using at least 4+ ground radials or several elevated radials. In a temporary or emergency situation, a single counterpoise can be used when cut to approximately 1/4 wavelength of the lowest operating frequency.

Ununs are intended for use with unbalanced antennas such as verticals and long wires. 
They will not work with balanced designs such as dipoles or loops and use with a balanced antenna may cause erratic operation and/or damage to the unit.


  Core Material   Custom mix low permeability ferrite by Fair Rite Products for maximum bandwidth.
  Cores are coated and sealed for long term durability.
  Winding Type   Single core with single bifilar wire pair wound as 4:1 unun.  
  Downward impedance transformation by factor of 4. i.e. 200 ohms to 50 ohms.
  Winding Material   Single bifilar winding of 14 gauge Heavy build polyamideimide Allex 240 Winding Wire
  Windings are inserted into Teflon tubes increasing total breakdown to 10,000 volts.  
  Power Rating   1 to 35 MHz - 2kW, 3kW intermittent.  35 to 54 MHz - 1kW, 2kW intermittent.
  Useable Frequency   1 to 54 MHz
  Insertion Loss   Less than .02db
  Connectors   SO-239 connectors are silver plated 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
  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.

Installation Notes