"Richard Clark" wrote in message
...
On Thu, 04 Mar 2004 18:18:46 GMT, "aunwin"
wrote:

Why must only series circuits be considered for radiators?.

Hi Art,

I don't know if there's a "must" to this.

At last.... at last somebody said
'I don't know'
Perhaps Walter will now say he doesn't know!


Every series circuit can be
seen as a parallel circuit; and on the flip side, every parallel
circuit can be seen as a series circuit. It is all a matter of where
you put your leads to drive/measure/load/receive.... The same
components vary only slightly in frequency from their being series
resonant or parallel resonate. Without that
drive/measure/load/receive path, there is no energy transfer and power
consumption is all strictly a matter of component ohmic loss.

Yes, partially understood , so to the question......



What is it about parallel circuits that make them unsuitable?

They are used every day to load up halfwave verticals, which in turn
are also parallel equivalent circuits.

Did you mean that? A halfwave vertical is a parallel circuit!

The input to the parallel
interface is performed through divider action (usually a tapped coil,
but could be through a capacitor divider).

Yes I know that but the question did say antennas didn't it?

You gave an answer to a question that was not asked. What you are refering
to is not for its radiation attributes is it? I hope we are not going into a
multi heading thread mode in less than 12 hours.


Is stagger tuning a parallel circuit ?

No, but it could be. Stagger tuning, by convention is a chain of
separately tuned circuits, be they RC, RL, or LC (or, of course RLC).

You mentioned the all important word of "tuned" so all of the above are
parallel circuits....right?

One RC or RL circuit exhibits a 6dB/Octave or 10dB/Decade roll-off.
One LC circuit exhibits twice that or a 12dB/Octave or 20dB/Decade
roll-off. Again, it is all a matter of connections for the identical
components (which will show a slight shift in parallel to series
resonance frequency - which is to say it is application
dependent).

I totally miss this point and probably the blame is mine. I think you are
saying that yes, they are parallel circuits, but you have an exception that
you want to point out i.e.slight shift in parallel to series...........

Not sure if you are saying 'yes'. I personaly think it is a parallel
circuit to which I would answer 'yes'.
Are you asking for some wriggle room? Two elements that are physically
separated is much too hard for me to describe as a series circuit. So I ask
the question in the context of the first two questions to prevent answers to
the like of 'just habit.'
Now I am not being awkward, believe me or I would not have responded. Force
12 has stagger tuning, if it is series devised then it gives more ammo to
the 'do not use parallel circuits for antennas' argument which seems to be
prevalent with antenna experts.

Two RC or two RL, or one RC with one RL in cascade constitute "stagger
tuning" irrespective of what frequencies their roll-off occur at (this
sets the stage for Bandwidth) and their sum contribution equal roughly
one LC circuit (which does not qualify as "stagger tuned") as long as
they share the same characteristic frequency (where the roll-off
occurs which is generally defined at the 3dB inflection).

Now, as to the expression "roll-off" used liberally above. All such
circuits may be called "de-emphasis" (where roll-off is evident) or
"pre-emphasis" (where roll-up would be more descriptive). The
application is strictly a matter of where the drive is applied, and
where the load takes its output.

I lost the point that you had in mind with the above and I wish you had not
mentioned bandwidth since it will bring another fork to the thread

73's
Richard Clark, KB7QHC

No rudeness intended anywhere Rich.. I seriously need reasonable specific
answers before I spend a lot of money.
Art