[TowerTalk] "Antenna Tuner"
ve4xt at mymts.net
ve4xt at mymts.net
Sun May 4 10:49:43 EDT 2014
May not have been the best example, but the point is that depending on the antenna, resonance and 50 ohms do not always coincide and that some form of matching is required.
The lower impedances may have been from shortened verticals as studied by Sevick.
A better example might have been a 5/8-wave, they're what, about 120 ohms? If you try to adjust the length of a 5/8 wave to get a pure 50-ohm non-reactive load, you won't have a 5/8-wave anymore.
The impedance of a end-fed 1/2-wave won't be anywhere close to 50 ohms, either, will it?
73, Kelly
ve4xt
Sent from my iPad
> On May 4, 2014, at 8:58 AM, "Peter Voelpel" <dj7ww at t-online.de> wrote:
>
> A lossless quarter-wave monopole has an radiation resistance of 35 ohms.
> To that all losses will be added and the result is the feed point impedance.
> That will never have an impedance of 12 ohms but 40-50 ohms or more.
>
> 73
> Peter
>
> -----Original Message-----
> From: TowerTalk [mailto:towertalk-bounces at contesting.com] On Behalf Of Kelly
> Taylor
>
> A resonant quarter-wave monopole over a decent ground might have an
> impedance of about 12 ohms.
>
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