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Old July 11th 05, 01:59 AM
Roy Lewallen
 
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Oops, I stand corrected -- thanks, Frank. Once again I read too hastily.
A *mass*/spring combination mimics an inductor/capacitor, of course. A
damper adds resistance. So a spring/damper combination would act more
like an RC or RL circuit, but with a little stray L or C from the
spring's mass.

Hope I don't have to give up my new title. Titles really impress folks
in some parts of the world.

Roy Lewallen, W7EL, ROW, ASI, OFC

Frank wrote:

Of course, I should have mentioned a mass/spring/damper (equivalent to
capacitor/inductor/resistor), not just spring/damper. I think the only
physical system that can not be entirely modeled as an electrical analog is
a thermal system; which has no inductor equivalent.

Frank


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Old July 11th 05, 02:29 AM
Frank
 
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"Roy Lewallen" wrote in message
...
Oops, I stand corrected -- thanks, Frank. Once again I read too hastily. A
*mass*/spring combination mimics an inductor/capacitor, of course. A
damper adds resistance. So a spring/damper combination would act more like
an RC or RL circuit, but with a little stray L or C from the spring's
mass.

Hope I don't have to give up my new title. Titles really impress folks in
some parts of the world.

Roy Lewallen, W7EL, ROW, ASI, OFC


No problem Roy. To be exact a mass is equivalent to a capacitor.
As in Newton's 2nd law: f = m*dv/dt, and its electrical analog
i = c*dv/dt, where "v" refers to velocity in the mechanical case,
and voltage in the electrical. I think this qualifies me to place the
letters "ASI" after my name. Well; I must admit I took a quick
look at my physical systems text book, so hope it does not
disqualify me.

Frank Meredith ASI



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Old July 11th 05, 05:55 AM
J. Mc Laughlin
 
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My EE students, noting that the characteristic equations are the same,
regularly convert mechanical problems (of the mass-spring-damper type) into
electrical problems, solve, and then convert back to mechanical answers.
Some ME students catch on and some just do not get it. Of course, it helps
if one is using SI units all round. I continue to be in awe of MEs who
always seem to know whether the "pounds" they are talking of are
sort-of-like mass, or sort-of-like force, or money. I have even had it
suggested that energy and power are sort-of the same thing.


I am keen on Roy being the collector of titles. I have quite enough for
a lifetime. 73 Mac N8TT etc.

--
J. Mc Laughlin; Michigan U.S.A.
Home:
"Roy Lewallen" wrote in message
...
Oops, I stand corrected -- thanks, Frank. Once again I read too hastily.
A *mass*/spring combination mimics an inductor/capacitor, of course. A
damper adds resistance. So a spring/damper combination would act more
like an RC or RL circuit, but with a little stray L or C from the
spring's mass.

Hope I don't have to give up my new title. Titles really impress folks
in some parts of the world.

Roy Lewallen, W7EL, ROW, ASI, OFC




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Old July 11th 05, 08:51 AM
Spike
 
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Roy Lewallen wrote:

Spike wrote:

Can this be the same idiot who thought that a spring/damper
combination was the mechanical equivalent of a coil and capacitor, on
the grounds that they both exhibited resonance?

from
Aero Spike


I'm that idiot. Actually, one of the very many. The equations for the
two systems are identical.

Roy Lewallen, W7EL, ROW, ASI
(Reg's Old Wife and now Aero Spike's Idiot. The titles just keep
accumulating. Of course I'm also a proud member of the OFC.)


Posting under the sock-puppet "Airy R. Bean", he said the following
quoted below, and to which I was referring. I leave it to you to spot
the glaring error. I very much doubt you said anything like this.

The original message was posted in sci.physics at 9:53 am on 21st
January this year.

"Reactance is characterised by the storage of energy.

In the case of the capacitor, you might think that your
AC source is the only voltage source in your circuit, but
after the first 1/4 cycle, the capacitor acts as a voltage source
and starts to give back the energy that it has stored.

The combined result of the two voltage sources, your
AC excitation and the capacitor itself, accounts for
the out-of-phase current waveform.

(This bothered me for years! How could the current
be non-zero if the AC driving voltage was zero?!)

The same analogy applies to springs and to shock absorbers;
the spring stores energy when stretched; the shock-absorber
stores energy when compressed. Both the spring and shock
absorber will return energy at some time and this exhibit reactance!"


from
Aero Spike
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Old July 22nd 05, 09:53 PM
John Smith
 
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I have always used the CFA as a mobile antenna!

Get with the program people, you will be hard pressed to find a better
antenna for this purpose!

As a shack antenna, it sucks!

However, what other antenna can you chuck a motor into, slap a
steering wheel and horn on and drive?

You guys are all wet, as usual... satisfied-smirk

John

"Polymath" wrote in message
...
Actually, just did a quick webbing and found enough to
realise that the claims are founded upon feet of clay.....

1. You do not separately excite the E and H fields because
if you excite an E field, you get a corresponding H field, and
vice-versa,
even if it is your intention to excite separately.

2. The differential forms of Maxwell describe the fields at _EVERY_
infinitesimal point and there is no way that the attempt to excite
two
separate fields from two separate mechanical contrivances will
result
in registration at every single point. Indeed, it is doubtful that
registration
will be achieved at all at any infinitesimal point. In any case, as
in (1) above,
your E field will have its H, and your H field will have its E field
already.

3. In the accepted equations describing the generated field,
radiation comes only
from accelerating charges. Thus the capacitive elements of the CFA
will
create the near field (decaying as 1/(r^2)) but not any radiated
field
(decaying as 1/r). I wonder if the measurements resulting in the
claims
for the CFA were made in the near field?

I wonder if the whole thing is intended as an elaborate hoax, and
that the
authors, in their original paper in Wireless World, relied on the
fact that
most readers' eyes would glaze over when faced with the maths of
vector
fields? (Remember, that in this NG we've had someone who boasts of
two degrees, one in maths and the other in electronics, stating that
e^(-jwt)
is a function that decreases with increasing time, thus indicating
that the
awarding of a degree together with the professing of mathematical
equations is no guarantee of competence!)

I suggest
http://farside.ph.utexas.edu/teachin...es/node53.html etc
as a good revising/learning/debunking cookbook. (Don't start from
node 53!)

"Polymath" wrote in message
...
I've just about got enough elec-and-mag theory to be
able to understand the claims made for the GM3HAT
CFA; any pointers to the patent claims?








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Old July 23rd 05, 10:14 AM
NunYa Bidness
 
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On Fri, 22 Jul 2005 13:53:42 -0700, "John Smith"
Gave us:

You guys are all wet, as usual... satisfied-smirk


I suppose then that you consider yourself to be firmly grounded in
reality.
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Old July 23rd 05, 01:24 PM
John Smith
 
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Firmly grounded?

Actually, when I am finished installing the mercedes turbo-jet engine
in the CFA, I plan on flying it!--well, after installing the carbon
graphite wings...

John

"NunYa Bidness" wrote in message
...
On Fri, 22 Jul 2005 13:53:42 -0700, "John Smith"
Gave us:

You guys are all wet, as usual... satisfied-smirk


I suppose then that you consider yourself to be firmly grounded in
reality.



  #8   Report Post  
Old July 23rd 05, 06:39 PM
NunYa Bidness
 
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On Sat, 23 Jul 2005 05:24:20 -0700, "John Smith"
Gave us:

Firmly grounded?


Yes. You made an all wet joke. I made an electrical joke that you
should have gotten.

Actually, when I am finished installing the mercedes turbo-jet engine
in the CFA, I plan on flying it!--well, after installing the carbon
graphite wings...


Perhaps you did.

Top posting is very bad.
  #9   Report Post  
Old July 23rd 05, 07:27 PM
John Smith
 
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OK.

It is like this, years ago, in the 1980's, when telnet was still being
used on the predecessors of newsgroups, there was no way to logically
organize "posts."

Still, into the 90's, most all "news clients" lacked any meaningful
way to organize threads and/or posts.

At the end of the 90's a few news clients managed to "get-it-together"
and organize threads and posts with pretty good results.

Now it is 2005. Windows xp comes with a completely functional news
reader which holds threads and posts in perfect order--no longer do I
have to have the text being responded to placed above the text which
is being issued in response. Still, many ancient news readers are in
use, and the users have not bothered to upgrade them. Also, many are
reading these posts from webpages...

That is all their responsibility now, if they are unwilling or unable
to setup a decent news reader and come up to speed, that is their
problem--there is NO longer a real need to bottom post, indeed, it
only slows down ones interaction with the group and places an
un-necessary burden to be cutting and pruning text...

.... the etiquette and use manuals of usenet need upgrading ...

I will be top posting...

end of story...

John

"NunYa Bidness" wrote in message
...
On Sat, 23 Jul 2005 05:24:20 -0700, "John Smith"
Gave us:

Firmly grounded?


Yes. You made an all wet joke. I made an electrical joke that you
should have gotten.

Actually, when I am finished installing the mercedes turbo-jet
engine
in the CFA, I plan on flying it!--well, after installing the carbon
graphite wings...


Perhaps you did.

Top posting is very bad.



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Old July 23rd 05, 07:30 PM
John Smith
 
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oh yeah...

It is a half-wave CFA. No ground plane/counterpoise is needed...
I live in calif, who worries about lightning here...
grin

John

"NunYa Bidness" wrote in message
...
On Sat, 23 Jul 2005 05:24:20 -0700, "John Smith"
Gave us:

Firmly grounded?


Yes. You made an all wet joke. I made an electrical joke that you
should have gotten.

Actually, when I am finished installing the mercedes turbo-jet
engine
in the CFA, I plan on flying it!--well, after installing the carbon
graphite wings...


Perhaps you did.

Top posting is very bad.





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