Where does an antenna "tuner" remove power? How does it remove power?
Where does the power go?
An antenna matching network is only a matching network. Every transceiver
today has a broadband matching device: a transformer in the output stage to
take a very low impedance (usually less than 5-ohms, real) to 50-ohms
real. Does this remove power generated by the output transistors? It's a
matching network similar to the matchbox or transmatch, a.k.a. antenna
"tuner".
Please explain explain how and why the matching network removes power and
where that power goes.
Dave - W?LEV
On Sun, Jan 31, 2021 at 6:52 PM Tony Michel <tonyfromjupiter@...>
wrote:
I agree! Kudos and thanks to Barry for this useful discussion of antennas.
My proposition: by the physical principle of conservation of energy can we
say that
the problem is to get energy out of the transmitter and into the feedline,
and have it stay
there, then we will put the best signal on the air? If we have an antenna
tuner at the
transmitter output, we can add capacitance or inductance as needed to make
the antenna
and feedline system appear resistive, taking power away. Where to? What
about where the
feedline meets the antenna? Should we try to match the feed to the
antenna. If we don't
match the feed and antenna then presumably we will have reactive currents
flowing in the
feedline, causing dissipation (power loss) much the same as poor "power
factor" causes
useless loss in AC power distribution systems. Thus we are motivated to
match the antenna
to the feedline at its feed point, so that we reduce the power bouncing
back and forth in the feedline.
Again, by conservation of energy, if we can get the power out of the
feedline, and into the antenna,
it will radiate, which we like. Whether the antenna is resonant, and where
we feed it is beside the point.
With a resonant antenna fed a a reasonable point, it's easier to match the
feed to the antenna.
Tony KD1IK
Lexington MA
--
*Dave - W?LEV*
*Just Let Darwin Work*
