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 Whats the differences between Unun Baluns, 1:1, 4:1, 9:1 
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Post Whats the differences between Unun Baluns, 1:1, 4:1, 9:1
I found the following answer to a question i get asked usually by newbies so i thought i would post up here it doesnt go into any great detail and hopefully will be of use (please note this isnt my wording ) just thought id share

a balun is a transformer. the ratios on baluns give you the ratio between output and input impedance so a 4:1 balun transforms 200 ohms to 50 ohms, a 1:1 means no impedance change. the word balun is made from BAL anced to UN balanced. if you remember from your foundation course dipoles are balanced antennas and need a balanced feed. coax is unbalanced and therefore needs some form of device to make it feed a balanced antenna correctly. hence a balun... and unun is literally and Unbalanced to Unbalanced transformer. ideal for random long wires, they are again, just impedance matching. a 9:1 unun transforms high impedance inputs to lower impedance that most atu's can handle without making any changes to the feed type... ie unbalanced to balanced.
To simplify a Balun, what you use to connect coax to a balanced antenna, such as a dipole, these are normally 1:1 ratio - Unun, used to connect coax to end fed antenna's, usually 9:1 ratio. 4:1 balun, like a 1:1, but allows connection of coax to say a carolina windom antenna, which has a feedpoint impedance of 200 ohms..
hope this is of use ...... :)

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