[Antennas] Re: increased ant bandwidths...

[Saandy Eban]

...why should it change?
	Try to look at the antenna AND the transmission line as a single
entity: as long as the antenna coupler brings the system to accept power
that power, minus ohmic losses, WILL get out! The conservation of energy law
works! 
	the main reason for not throwing the open wire feeder out is this: a
SWR of 10 or 20 will not add more than a few % of power loss, directly
attributable to the SWR! Because of this it hardly matters what you see
there: what matters is that the radio will see an SWR it can live with. If
you ensure that, everythin going into the system WILL get out, again,
barring the inherent ohmic losses. On the other hand, if you can compensate
for such SWR's, you can cover half of the HF spectrum with one antenna. 
An SWR meter has no place there (the antenna side, that is) but an RF
ammeter will allow you toverify a current maximum in the antenna, which is
basically what counts.
Saandy	4Z5KS


-----Original Message-----
From: antennas-bounces at mailman.qth.net
[mailto:antennas-bounces at mailman.qth.net] On Behalf Of Jack Painter
Sent: Saturday, April 29, 2006 8:50 PM
To: Antennas reflector
Subject: RE: [Antennas] Re: increased ant bandwidths...

Bob and Roy,

It sounds like you both agree that power output from the transmitter is the
only objective of any antenna tuner. What happens after that we have to
accept if we want wider use of each antenna.

If antenna tuners were placed at the feedpoint of the antenna, there would
be little reflected power on the transmission line before it. An antenna
coupler is always as close to the feedpoint as possible for this reason.

When we want more tuning options in non-weatherproof assemblies right at our
fingertips (and inside the zone of our lightning protection system), we have
to accept the consequences. An inside antenna tuner still protects the
transmitter and the operator, as long as we remember the output of the tuner
(like a coupler) is 'hot' in more ways than temperature.

Regards,

Jack

-----Original Message-----
From: Robert Lay (W9DMK)

> Ordinarily RF power meters are located at the INPUT of an 'antenna 
> tuner.'
>
> 73,   Roy     K6XK

Good point, Roy.

We wouldn't want anyone finding out how little power comes OUT of the
antenna tuner - that would discourage people from using them.

Even worse would be to have an SWR meter on the output side of the tuner.
Then they would really be pissed to see that the SWR does NOT CHANGE AT ALL
in the transmission line - Hi!

73 de W9DMK - Bob Lay, Dahlgren, VA
http://www.zaffora.com/W9DMK/W9dmk.html
w9dmk at crosslink.net

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