Model 4130 - 4:1 Unun 1.5 - 54 MHz - 300 watts

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  • Model 4130 - 4:1 Unun 1.5 - 54 MHz - 300 watts
  • Model 4130 - 4:1 Unun 1.5 - 54 MHz - 300 watts

Available to order Saturday, April 20th


Designed for use with end fed wire antennas and multiband verticals,  this unun is small, compact and perfect for quick portable/emergency installations. This 4:1 Unun (200-50 ohms) will easily handle 300 watts and covers 1.5 - 54 MHz. Using this unun will allow transceivers with internal antenna tuners to work most if not all HF bands.  A 28-31  foot wire will allow 40 thru 10 meter coverage and a 43-50 foot wire will provide access to 80 thru 10 meters.  A good ground or counterpoise is also required.

This model also works well with any of the 19, 31 and 43 foot portable verticals and the wing nut model makes setup and breakdown quick and easy.  If you have a 43 foot vertical, a long wire over 200 feet and/or want to run high power, consider the model 4132s or model 4134s
which provides additional inductive reactance for enhanced performance on the lower bands. 

Installation Notes and Recommended Wire Lengths


The enclosure for our low power units is small, lightweight and portable, but not intended for long term or permanent outdoor use. If used in a permanent outdoor installation, additional attention must be given to weatherproofing and strain relief. Damage caused by such use is not covered under our warranty.


BNC & N connectors are available in "Accessories & Connectors" section of our website




  Core Material   Custom mix low permeability ferrite by Fair Rite Products for maximum bandwidth.
  Core is 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   Bifilar winding of silver flashed 18 gauge Teflon insulated wire. 
  5000v breakdown voltage
  Power Rating   1.5 to 35 MHz - 300 watts, 35 to 54 MHz - 200 watts.  
  All ratings based on resonant load. High SWR will reduce power handling ability.
  Useable Frequency   1.5 to 54 MHz
  Insertion Loss   Less than 0.1db
  Connectors   SO-239 connectors are silver plated with Teflon insulation.
  Alternate connectors and Mounting Options are available in the Accessories section.
  Hardware   All Stainless Steel
  Enclosure Type   Polycarbonate (ABS) box with bottom plate that fits flush with the case
  Plate is an exceptional fit that can be easily weatherproofed if desired.
  Dimensions   Very compact 3x2x1.5 inch - Link to dimensional drawing
  Additional Info   Very high efficiency (98-99%). 

Installation Notes


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