HF Impedance Transformer Kits

50:450 ohm (9:1) Balun or Unun Core Kit, 1.8-30 MHz, 250 watts PEP, end fed, T2FD antenna

SKU BA-9-250
In stock
Product Details

Model BA-9-250 is a 9:1 balun/unun kit used to translate a 50 ohm input up to 450 ohms at RF power levels up to 250 watts PEP when used with a matched load. With a matched 450 ohm load the SWR over the frequency range 1.8 to 30 MHz is shown in the following table measured with an AIM 4170 network analyzer. Notice that the conversion from 450 to 50 ohms is very consistent from 1-31 MHz and SWR is less than 2:1 over most of the range allowing easy tuning by most radio internal antenna tuners or an external tuner. Graph is for a 9:1 unun often used with long wire or end fed antennas.

BA-9-250 Graph

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These impedance transformer kits have been designed for the Do-It-Yourself (DIY) enthusiast and Instructor workshops on baluns and ununs for antenna matching and RFI use.

The impedance transformers are classified in ratios of 2:1 (100:50 ohm) to 16:1 (800:50 ohm).  The outputs can be configured as balanced (Balun) or as unbalanced (unun) with respect to the inputs which are considered all unbalanced coax at 50 ohms.  All impedance transformers are designed for 1.8-31 MHz unless otherwise specified.