aunwin wrote:
The half power thingy I presume is understood by all so IS something very
exciting to be revealed that shows that the dipole is really an efficient
radiator after all, but only if you put a class C amplifier on it?

Art, I assume you know that Class-C amplifiers are not usually used
for SSB since they are not linear for SSB. The basic confusion is
between linear systems and non-linear systems. If the amplifying
device (singular) conducts over the entire 360 degrees of an RF cycle
and the output waveform is a reasonable copy of the input waveform,
then that device is said to be linear. If you have two amplifying devices
operating in anything except Class-A operation, the output of each
individual device is not linear. That's the kicker. The "two non-linear
device" option is not available at the antenna for receiving purposes.
A normal dipole cannot receive Class-C (non-linear) signals.
--
73, Cecil, W5DXP

Cecil
I am talking about the half power thingy with respect to a series circuit of
which a antenna is designed around. Reg politely made a separate thread on a
specific part of that thread which referred to impedance, presumably because
Q was being bandied about where he thought probably it was irelevant.
Am I wrong to think that because a different thread was not made
the impedance question and amplifiers was relavent and somebody was not
being destructive/impolite?
Now to your pont of what is the kicker...a normal dipole cannot receive
Class-C (non linear signals)"?
Having being told about this thing that somebody read somewhere,
where is it leading to? Seems like I entered a class on engineering
and after 5 minuites I am wondering what sort of professor I had that not
only just read books out loud for his money but thought it was O.K. to read
from a wood working book. Can't we assume that a antenna is a closed series
circuit containing only passive
items ? If you have in mind that we must we consider an antena as a Class
something or other amplifier when determining its impedance then I am
hopelessly lost in a thread that can only end up nasty like some others did
and drive some more people away
because somebody wanted to play games of obstruction with the intent to
annoy. Now I see that somebody decided to change this
thread heading instead of starting a new thread . Now we are talking about
RMS meters and how they can be used ? Are we talking digital or analogue,
hand held or otherwise, high enough accuracy to satisfy all ( Nah that is
asking to much) Well it is an antenna newsgroup so it must radiate ,
somebody read it in a book and assumes that all are unaware of it so he
wishes to describe it
so others can make sense of what he read and why he read it!
Regards
Art
I am not pointing the finger at you Cecil, I have no idea who the culprit is
or what his intent is.


?Cecil Moore" wrote in message
...
aunwin wrote:
The half power thingy I presume is understood by all so IS something
very
exciting to be revealed that shows that the dipole is really an
efficient
radiator after all, but only if you put a class C amplifier on it?

Art, I assume you know that Class-C amplifiers are not usually used
for SSB since they are not linear for SSB. The basic confusion is
between linear systems and non-linear systems. If the amplifying
device (singular) conducts over the entire 360 degrees of an RF cycle
and the output waveform is a reasonable copy of the input waveform,
then that device is said to be linear. If you have two amplifying devices
operating in anything except Class-A operation, the output of each
individual device is not linear. That's the kicker. The "two non-linear
device" option is not available at the antenna for receiving purposes.
A normal dipole cannot receive Class-C (non-linear) signals.
--
73, Cecil, W5DXP

Art, KB9MZ wrote:
"Can`t we assume that an antenna is a closed series circuit containing
only passivee items?"

Sure, but you have an incomplete representation. An antenna is coupled
more or less to the entire universe. It is usually tightly coupled to a
radio or similar apparatus by some mutual impedance which makes a
codependency.

Best regards, Richard Harrison, KB5WZI

aunwin wrote:
Can't we assume that a antenna is a closed series
circuit containing only passive items ?

A passive antenna, when it is receiving a signal, is a pretty good
approximation to a Thevenin Equivalent circuit. The received
signal is the generator. The generator impedance is the radiation
resistance (and the lossy R's). We've got a transmission line and
usually a 50 ohm load in the receiver.

If you have in mind that we must we consider an antena as a Class
something or other amplifier when determining its impedance then I am
hopelessly lost in a thread that can only end up nasty like some others did

Why not, for the purposes of limiting the discussion, consider only
a Thevenin Equivalent 50 ohm source for the transmitter? That way,
the entire system will be linear and easy to discuss.

I am not pointing the finger at you Cecil, ...

If you were, which one would it be? :-)
--
73, Cecil, W5DXP

No I can't remember ever putting a finger/s up at anybody.
But I have this feeling that this thread is now long enough and has included
so many subjects of discussion that we have the beginnings of a full scale
augument again. However if it means that this is the time a certain person
leaves the group in discussed
then no harm done. Forget antennas and impedance and the subject change you
are advocating, let the row start now, say something,
anything so we get a repeat of the last one. Can't you say balonney or
bull**** at the next guru and tell something different to another guru and
blame it on the first guru? Throw a fishing pole with a carrot on it!
Art
Art

Art
"Cecil Moore" wrote in message
...
aunwin wrote:
Can't we assume that a antenna is a closed series
circuit containing only passive items ?

A passive antenna, when it is receiving a signal, is a pretty good
approximation to a Thevenin Equivalent circuit. The received
signal is the generator. The generator impedance is the radiation
resistance (and the lossy R's). We've got a transmission line and
usually a 50 ohm load in the receiver.

If you have in mind that we must we consider an antena as a Class
something or other amplifier when determining its impedance then I am
hopelessly lost in a thread that can only end up nasty like some others
did

Why not, for the purposes of limiting the discussion, consider only
a Thevenin Equivalent 50 ohm source for the transmitter? That way,
the entire system will be linear and easy to discuss.

I am not pointing the finger at you Cecil, ...

If you were, which one would it be? :-)
--
73, Cecil, W5DXP