Thread: Baluns?
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Old September 2nd 08, 12:51 PM posted to rec.radio.amateur.antenna
Cecil Moore[_2_] Cecil Moore[_2_] is offline
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Default Baluns?
wrote:
On Sep 1, 3:25 pm, Cecil Moore wrote:
Actually, 1000 ohms is pretty liberal. For instance, on
15m, the G5RV coax sees 36+j230 ohms or about 233 ohms.
The balun needs to be 10x that value or 2330 ohms.

Why not 500 ohms, assuming a 50 ohm source and transmission line?

Be the current making a choice of paths at a junction.
How much of you would flow through 500 ohms and how much
would flow through 233 ohms? (If 500 ohms is the total
impedance seen by the shield current looking back toward
the source, about 1/3 of the current would flow back
through the 500 ohms down the coax.)

http://eznec.com/Amateur/Articles/Baluns.pdf
--
73, Cecil http://www.w5dxp.com
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