[TowerTalk] More balun advice

[Earl Morse]

The antenna impedance won't change, it will still look like a typical dipole with or without the balun.

The balun will act like a transformer over a fixed set of frequencies depending on core material, # of turns, and inter-winding capacitance.  The high frequency limit would be determined by core material and inter-winding capacitance and the low frequency by the core material and # of turns.

# of turns and inter-winding capactance are mutually exclusive meaning that for the improvement you get at lower frequencies by adding more turns you will lose at the higher frequencies due to the increase in inter-winding capacitance.

A typical balun when terminated in its design load impedance would show less than 50 ohms at the low end of its frequency range, maintain 50 ohms through its usable frequency range, then go high when it hits its self resonant frequency at the high end of its usefulness.

Read W2FMI and K9YC for the in depth discussion on balun design.

Earl
N8SS
 
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Message: 5
Date: Tue, 10 Nov 2015 16:42:14 -0500 (EST)
From: "John Santillo N2HMM" <n2hmm at warwick.net>
To: towertalk at contesting.com
Subject: [TowerTalk] More balun advice
Message-ID:
	<cc324aba9e3904da1cbd15581e34568d.squirrel at mail.warwick.net>
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All,

Since we're on a roll about BALUN's I have a question to the group.  If a
BALUN designed for 80-10 is used on a 160M antenna (say a dipole), will
the impedance of the 160M antenna increase?


73,

John
N2HMM



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