Amazon.com: Balun One Nine v2 - Small Low-Cost 9:1 (1:9) Balun with Input Protection & Enclosure for HF & Shortwave. Great for Software Defined Radio (RTL-SDR & SDRPlay), Ham It Up, and
1:1, 9:1, 49:1 Matching Units - What's the difference? - YouTube
9:1 Magnetic Longwire Balun / Unun – M0UKD – Amateur Radio Blog
9:1 Magnetic Longwire Balun / Unun – M0UKD – Amateur Radio Blog
50:450 ohm (9:1) Balun or Unun Core Kit, 1.8-30 MHz, 250 watts PEP, end fed, T2FD antenna