Hello Colin:
Thank you for that informative description of antenna tuners.
73,
David S. Pearson-wa4dsp
-----Original Message-----
From: Colin McDonald
Sent: Monday, June 30, 2014 12:58 PM
To: [log in to unmask]
Subject: Re: practical functions of antenna tuners?
An antenna tuner foolls the radio into thinking the antenna is a 50 ohm
load.
This allows the radio to put out max power. The tuner's job is to match the
antenna and feedline system to what the radio wants to see for max power
output.
This is the case with any antenna system that doesn't present a 50OHM
feedpoint and a resonant radiator at the frequency you are trying to use.
The term, fooling the radio, is used, because the antenna system doesn't
change, it's not matched and it's not tuned, but the antenna tuner somewhere
in the feedline will give the radio 50Ohms to look at instead of whatever
the system presents otherwise.
So yeah, to answer your question, an antenna tuner does help to allow as
much power as possible to get to the antenna thus making the system more
efficient...but it does not make the antenna resonant or better than it was
before the tuner.
Ultimately, one should use an antenna that is specifically designed to be
resonant on the frequencies being used. However, with multi-band antennas,
they are a compremise generally on all bands, and therefore require a tuner
in order for the radio to work efficiently and put out the most power that
it can.
The best signals you hear on the air will almost invariably be coming from a
station using a resonant antenna and no tuner.
There is a reason they are the best signal, and not because they are using
power, but because they are maximizing efficiency instead of compensating
for poorly tuned antennas.
A G5RV is an antenna that gets close on allot of bands, but is rather poorly
tuned for any ham band thus requiring a tuner. Of course they work, and
they work quite well because they do tend to radiate allot with the design
using the latter line, and when you get enough wire up in the air you will
get a signal out but they're no where near a resonant antenna and will not
perform as well as a mono band dipole given the same height and variables.
But the advantage is you can get out on more bands with one antenna, and
it's close enough for many using a tuner.
73
Colin, V A6BKX
--------------------------------------------------
From: "David Pearson" <[log in to unmask]>
Sent: Monday, June 30, 2014 10:11 AM
To: <[log in to unmask]>
Subject: practical functions of antenna tuners?
> Hello List:
>
> A previous post suggested that an antenna tuner "fooled"an antenna into
> thinking that the antenna was resonant on a particular band/frequency(I
> think that he was referring to verticals).
>
> My question concerns multi-band wire horizonntals(a 10-40 half-size g5rv
> for
> example).
>
> In this situation, is an antenna tuner performing the same function as it
> did with the vertical("fooling" the feed system into believing it's
> matched,
> or does it perform some other positives(better power transfer, etc.)?
>
> Sincerely yours,
>
>
>
> David S. Pearson-wa4dsp
>
>
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