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ATU - Internal Tuner

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crmabbott

ATU - Internal Tuner

Just a thought I have always heard the tuner at the feed point of the antenna defined [SGC] as a coupler. Because it is making a tank circuit at the feed point of the antenna. Now the 'Tuner' when it works takes in both the antenna and the coax as what it sees as the load. The coupler has some trouble tuning if in fact it is far from antenna. I have also heard the coupler is better than tuner and tuner is better than the coupler, but no matter for this discussion.

If the radio has an internal tuner and the output of radio is feeding a coupler at the feed point of antenna isn't the system going to be a little odd trying to adjust for each other? I would think you need a reliable way to lock either one of them out and let signal do a pass through.

Just my thoughts..

Chuck AA8VS

Date: Sun, 26 Oct 2008 16:49:31 -0600
From: Dale Putnam <<A onclick="return doCompose(this);" href="http://mailcenter.comcast.net/wmc/v/wm/4905D82E000D7683000041C622070208539B9B010D0D0E039D0C?cmd=ComposeTo&adr=daleputnam%40hotmail%2Ecom&sid=c0">daleputnam@...>
Subject: RE: [Elecraft] ATU vs. External Tuner
To: Sandy <<A onclick="return doCompose(this);" href="http://mailcenter.comcast.net/wmc/v/wm/4905D82E000D7683000041C622070208539B9B010D0D0E039D0C?cmd=ComposeTo&adr=ebjr37%40charter%2Enet&sid=c0">ebjr37@...>, John Buck <<A onclick="return doCompose(this);" href="http://mailcenter.comcast.net/wmc/v/wm/4905D82E000D7683000041C622070208539B9B010D0D0E039D0C?cmd=ComposeTo&adr=kh7t%40arrl%2Enet&sid=c0">kh7t@...>, Frank
MacDonell <<A onclick="return doCompose(this);" href="http://mailcenter.comcast.net/wmc/v/wm/4905D82E000D7683000041C622070208539B9B010D0D0E039D0C?cmd=ComposeTo&adr=kd8fip%40g mail%2Ecom&sid=c0">kd8fip@...>
Cc: Elecraft <<A onclick="return doCompose(this);" href="http://mailcenter.comcast.net/wmc/v/wm/4905D82E000D7683000041C622070208539B9B010D0D0E039D0C?cmd=ComposeTo&adr=elecraft%40mailman%2Eqth%2Enet&sid=c0">elecraft@...>
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The balanced antenna, center fed, with balanced line, is the lower loss system
of many. The fun part... is that while looking for inexpensive feedline, I've
found that the "poor, fast replaced" speaker lead wire... you know the stuff,
clear, copper, and only two conductors, work out very nicely for an antenna. In fact... a broad b anded, dipole can be fashioned out of that wire, with the
two elements having the ends twisted together, and still using just one run of
the wire for feed, works right nice. The balanced line feeds through walls and
up past the insulation nicely too. And the T-1 tunes it real nice. --...
...--Dale - WC7S in Wy

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Don Wilhelm-4

Re: ATU - Internal Tuner

Chuck, 'coupler' or 'tuner' is simply a matter of semantics, they are
both the same thing. Whether you choose to refer to the remote tuner as
a coupler or not to provide a distinction or not is your choice, but I
do not believe that usage is universal.

The purpose of all such devices is to match the antenna to the feedline
(when located at the antenna feedpoint), or to match the
antenna/feedline combination to the output requirements of the
transceiver (when located in the shack).

In the case where the feedline is 50 ohm coax and the match is done at
the antenna, there is no need for a tuner at the transceiver end since
the SWR on the coax will be sufficiently low to match the transceiver -
besides, this technique keeps the feedline losses low.

If inherently low loss feedline (true open wire line is the lowest with
dry ladder line a close second), there is no need to match the antenna
to the feedline and all matching can be done at the transition between
the parallel feedline and coax.

Of course, those who are fortunate to have only resonant coax fed
antennas, there is no need for a tuner anywhere in the system.

The K3 internal tuner can be put into bypass state when you are using a
remote tuner.

73,
Don W3FPR

[hidden email] wrote:

> Just a thought I have always heard the tuner at the feed point of the
> antenna defined [SGC] as a coupler. Because it is making a tank
> circuit at the feed point of the antenna. Now the 'Tuner' when it
> works takes in both the antenna and the coax as what it sees as the
> load. The coupler has some trouble tuning if in fact it is far from
> antenna. I have also heard the coupler is better than tuner and tuner
> is better than the coupler, but no matter for this discussion.
>
> If the radio has an internal tuner and the output of radio is feeding
> a coupler at the feed point of antenna isn't the system going to be a
> little odd trying to adjust for each other? I would think you need a
> reliable way to lock either one of them out and let signal do a pass
> through.
>