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12 sie 2016 · In many cases, the impedance can be transformed with the help of a 9:1 unun (unbalanced input to unbalanced output). See the figure at right. A 9:1 unun is a transformer that reduces the impedance at the input by a factor of 9.
4 cze 2021 · Easiest way to find out is to build it and measure empirically. Using triple windings allows closer wire spacing between the transformer input and output (primary and secondary) windings which can improve the magnetic coupling coefficient.
Figure 3 Wiring of the 9:1 voltage unun. Note this drawing shows winding connections and not the number of turns required. See article for details.
The heart of the Un-un uses a Type 43 [FT240-43] core and consists of a trifilar [3 wire] winding arrangement around the core. The wires are wound to create a 9:1 transformer and would ideally suit an end-fed long wire antenna fed against ideally – a good counterpoise, or a good radial system.
21 maj 2022 · The first link shows the typical 9:1 UnUn while your second link is about BalUns. I assumed from the title, the goal was to make an UnUn. Specifically a 9:1. The OP was only testing from 3-30MHz, with a worse case VSWR of 1.4:1. Again, I want to be clear that I have no use for such a device and am only playing around.
11 lis 2022 · Take your best shot on wire lengths, attached to the LDG 9:1 unun, go into the POTA park, hang your antenna, and activate the park. You'll learn soooo much and can adjust/fine tune/make it better next time.
The toroid is a T130-2 Iron Powder core, with 3 x 9 turns of 18SWG enammeled copper wire, and the connections can be seen below. The triple winding connections. 8 turns is shown here, but more turns is preferred. 10 would be ideal.
