Kurt Sterba’s Korner

50:200 ohm (4:1) HF Balun or Unun Core Kit, 3-31 MHz, 250 watts

SKU BA-4-250
$19.95
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50:200 ohm (4:1) HF Balun or Unun Core Kit, 3-31 MHz, 250 watts
Product Details
Input ohms/Output ohms: 50 in, 200 out
Frequency Range < 2:1 SWR (MHz): 1-31
PEP Power Rating (watts): 250

Model BA-4-250 is a 4:1 voltage balun/Unun kit (assembly required from parts supplied) used to translate a 50 ohm input up to 200 ohms at power levels up to 250 watts when used with a matched load. With a matched load the SWR will not exceed 2:1 over the frequency range 1.8 to 30 MHz.

The kit consists of a 1.4" diameter ferrite core, two colors of insulated wire. a UHF connector with stainless steel hardware, and an instruction manual with directions to connect the kit as a 4 to 1 balun (balanced coax to balanced antenna like zepp or from 450 ohm feeder line to coax for a tuner) or 4 to 1 unun (unbalanced coax to unbalanced antenna like end fed or random wire).

This balun will also transform at 4:1 for a wide variation of load impedances. Shown below are AIM 4170 SWR results for a 200 ohm load. This balun gives near perfect transformation through 30 Mhz with a SWR under 1.25 . Light blue vertical bars are ham bands starting at 160 meters at left to 10 meters at right.

BA 4 250 SWR 1 31 Mhz png - Kurt Sterba's Korner

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