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Blaster posted:

"and there was me thinking 1/2 waves were resonant."

an end fed 1/2 λ is not self-resonant however a center fed 1/2 λ is self-resonant.

a wire 90, 270, 450 (any odd number of 1/4 wl, in length) degrees long @ any given frequency is i.e., SELF RESONANT, not "resonant." theres a difference.
1 λ = 360 degrees. a full size, self resonant 1/4 λ can be fed directly with 50 ohm feedline without matching as in the example posted earlier.

any antenna not capable of SELF RESONANCE can be made RESONANT if the reactance can be dumped by an opposite reactance of equal amplitude, where as in the case of a SELF RESONANT antenna there is no reactance present when the antenna is adjusted for X = 0 simply by adjusting the length, the same thing that is really taking place when you ADJUST the length of a loaded 1/4λ mobile antenna while mistakenly believing that you are changing the swr. all you're changing is the resonant frequency of the antenna up and down across the antenna bandwidth to find a lower swr at some other frequency. that's not impedance matching. just look at any swr bandwidth chart to see what is actually happening. if you're going to affect the swr on the feedline then something needs to change @ the antenna-feedline or transmitter-feedline terminal connection in the case of either reflectionless load matching or feedline input matching.

<blockquote data-quote="freecell" data-source="post: 775916" data-attributes="member: 30">Blaster posted:&quot;and there was me thinking 1/2 waves were resonant.&quot;an end fed 1/2 λ is not self-resonant however a center fed 1/2 λ is self-resonant. a wire 90, 270, 450 (any odd number of 1/4 wl, in length) degrees long @ any given frequency is&nbsp; i.e., SELF RESONANT, not &quot;resonant.&quot; theres a difference.1 λ = 360 degrees. a full size, self resonant 1/4 λ can be fed directly with 50 ohm feedline without matching as in the example posted earlier.any antenna not capable of SELF RESONANCE can be made RESONANT if the reactance can be dumped by an opposite reactance of equal amplitude, where as in the case of a SELF RESONANT antenna there is no reactance present when the antenna is adjusted for X = 0 simply by adjusting the length, the same thing that is really taking place when you ADJUST the length of a loaded 1/4λ mobile antenna while mistakenly believing that you are changing the swr. all you&#039;re changing is the resonant frequency of the antenna up and down across the antenna bandwidth to find a lower swr at some other frequency. that&#039;s not impedance matching. just look at any swr bandwidth chart to see what is actually happening. if you&#039;re going to affect the swr on the feedline then something needs to change @ the antenna-feedline or transmitter-feedline terminal connection in the case of either reflectionless load matching or feedline input matching.</blockquote>

[QUOTE="freecell, post: 775916, member: 30"] Blaster posted: "and there was me thinking 1/2 waves were resonant." an end fed 1/2 λ is not self-resonant however a center fed 1/2 λ is self-resonant. a wire 90, 270, 450 (any odd number of 1/4 wl, in length) degrees long @ any given frequency is i.e., SELF RESONANT, not "resonant." theres a difference. 1 λ = 360 degrees. a full size, self resonant 1/4 λ can be fed directly with 50 ohm feedline without matching as in the example posted earlier. any antenna not capable of SELF RESONANCE can be made RESONANT if the reactance can be dumped by an opposite reactance of equal amplitude, where as in the case of a SELF RESONANT antenna there is no reactance present when the antenna is adjusted for X = 0 simply by adjusting the length, the same thing that is really taking place when you ADJUST the length of a loaded 1/4λ mobile antenna while mistakenly believing that you are changing the swr. all you're changing is the resonant frequency of the antenna up and down across the antenna bandwidth to find a lower swr at some other frequency. that's not impedance matching. just look at any swr bandwidth chart to see what is actually happening. if you're going to affect the swr on the feedline then something needs to change @ the antenna-feedline or transmitter-feedline terminal connection in the case of either reflectionless load matching or feedline input matching. [/QUOTE]

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