What if the source doesn't or can't dissipate?

--
73
Hank WD5JFR
"Cecil Moore" wrote in message
...
Henry Kolesnik wrote:
I know they work! One of my reasons for asking the question is I've
not
found any mention in the literature of where the
"attenuation/rejection/reflection/filter residue" goes.

An open 1/4WL stub detours all the associated frequency
energy into the stub and then reflects it back to the source.
Consider the following:

XMTR---------feedline-------+----load
|
| 1/4WL
| open
| stub

The stub causes complete destructive interference between the
forward voltage and reflected voltage at the mouth of the stub.
Since the net voltage at the mouth of the stub is zero, no
current flows into the load. All the current in the feedline
is flowing in the stub and is reflected at the open end. The
reflected waves head back to the source. Therefore, for lossless
feedlines, all the attenuation/interference occurs in the source.
Of course, for real-world feedlines, I^2*R losses will occur
because of the high SWR at the associated frequency.

The effect of the above stub is much like shorting out the load.
Shorting out the load increases the dissipation in the source.
--
73, Cecil http://www.qsl.net/w5dxp

Henry Kolesnik wrote:
What if the source doesn't or can't dissipate?

Heh, heh, you're on your own for that discussion. I personally
believe it is possible for reflected energy to wind up decreasing
the power consumption from the DC source that is supplying the finals,
which winds up decreasing the load on the 60 Hz power grid, which
decreases the oil required from the Middle East, which tends to
decrease the possibility of world war, which bodes well for the human
race, but that is another thread for another time.
--
73, Cecil http://www.qsl.net/w5dxp



-----= Posted via Newsfeeds.Com, Uncensored Usenet News =-----
http://www.newsfeeds.com - The #1 Newsgroup Service in the World!
-----== Over 100,000 Newsgroups - 19 Different Servers! =-----

Cecil Moore wrote:

SNIP

Heh, heh, you're on your own for that discussion. I personally
believe it is possible for reflected energy to wind up decreasing
the power consumption from the DC source that is supplying the finals,
which winds up decreasing the load on the 60 Hz power grid, which
decreases the oil required from the Middle East, which tends to
decrease the possibility of world war, which bodes well for the human
race, but that is another thread for another time.
--
73, Cecil http://www.qsl.net/w5dxp


Good engineering CAN solve the world's problems!!!

Just use enough 1/4 wavelength stubs and we can totally eliminate the #1
or #2 cause of international tension!!

Now, the Oil exporting states will face economic ruin! We will have to
give them foreign aid!! Damn ... taxes will have to go up!! That means
we have to elect a Demo Krapp as president.

Cecil, I didn't know you were campaigning for what's his name!!

I better be careful or my tongue may slip out of my cheek.

Sometimes, it's useful to think about problems such as this in terms of
analogous systems that behave in similar ways.

For example, imagine a gasoline-powered engine driving a water pump though a
friction belt and pulley. The pump is attempting to pump water into a short
plugged pipe (shorted transmission line). After the first couple of seconds
the reflected water from the plugged end creates a back pressure on the
pump, a situation in which the pump is then not capable of delivering
additional water to that which is stored in the pipe. Now, a number of
things can occur, short of mechanical failure of some part of the system:

1) the belt between the motor and pump can start to slip, dissipating the
energy generated by the motor as heat lost to friction in the belt and
pulley

2) the motor can slow or cease to function, incapable of working against the
increased torque (impedance) created by the belt that has been constrained
by the pump that can't pump water into the plugged pipe.

In case 1), the power is being generated by the motor, but it is not being
delivered to the load. It is being dissipated (converted to heat) `in
between.
In case 2), the power simply cannot be created. The motor can't work against
such a load. The power is not being dissipated anywhere -- it's simply not
being generated. As Cecil has suggested, in this case, the engine stops,
which stops using gasoline, which reduces the demand on the Middle East oil
supply, which lowers prices, which .....

Case 2) is not one in which reflections "cancel" the energy being generated,
although it can be thought of that way. Energy can't be "canceled" ( a
fundamental law). If a generator isn't delivering energy to a load, it's
because the energy either doesn't exist (isn't being generated), or it's
being rerouted, stored, or being converted to another form.

Although this analogy could be complicated by making it a pumping system
that generates sinusoidal water pressure waves with wavelength-related pipe
lengths, it doesn't need to be for it to work.

Al WA4GKQ


"Cecil Moore" wrote in message
...
Henry Kolesnik wrote:
What if the source doesn't or can't dissipate?

Heh, heh, you're on your own for that discussion. I personally
believe it is possible for reflected energy to wind up decreasing
the power consumption from the DC source that is supplying the finals,
which winds up decreasing the load on the 60 Hz power grid, which
decreases the oil required from the Middle East, which tends to
decrease the possibility of world war, which bodes well for the human
race, but that is another thread for another time.
--
73, Cecil http://www.qsl.net/w5dxp



-----= Posted via Newsfeeds.Com, Uncensored Usenet News =-----
http://www.newsfeeds.com - The #1 Newsgroup Service in the World!
-----== Over 100,000 Newsgroups - 19 Different Servers! =-----

Better specify the kind of pump because a centrifugal will have a different
outcome versus a positive displacment!

--
73
Hank WD5JFR
"Al" wrote in message
...
Sometimes, it's useful to think about problems such as this in terms of
analogous systems that behave in similar ways.

For example, imagine a gasoline-powered engine driving a water pump though
a
friction belt and pulley. The pump is attempting to pump water into a
short
plugged pipe (shorted transmission line). After the first couple of
seconds
the reflected water from the plugged end creates a back pressure on the
pump, a situation in which the pump is then not capable of delivering
additional water to that which is stored in the pipe. Now, a number of
things can occur, short of mechanical failure of some part of the system:

1) the belt between the motor and pump can start to slip, dissipating the
energy generated by the motor as heat lost to friction in the belt and
pulley

2) the motor can slow or cease to function, incapable of working against
the
increased torque (impedance) created by the belt that has been constrained
by the pump that can't pump water into the plugged pipe.

In case 1), the power is being generated by the motor, but it is not being
delivered to the load. It is being dissipated (converted to heat) `in
between.
In case 2), the power simply cannot be created. The motor can't work
against
such a load. The power is not being dissipated anywhere -- it's simply not
being generated. As Cecil has suggested, in this case, the engine stops,
which stops using gasoline, which reduces the demand on the Middle East
oil
supply, which lowers prices, which .....

Case 2) is not one in which reflections "cancel" the energy being
generated,
although it can be thought of that way. Energy can't be "canceled" ( a
fundamental law). If a generator isn't delivering energy to a load, it's
because the energy either doesn't exist (isn't being generated), or it's
being rerouted, stored, or being converted to another form.

Although this analogy could be complicated by making it a pumping system
that generates sinusoidal water pressure waves with wavelength-related
pipe
lengths, it doesn't need to be for it to work.

Al WA4GKQ


"Cecil Moore" wrote in message
...
Henry Kolesnik wrote:
What if the source doesn't or can't dissipate?

Heh, heh, you're on your own for that discussion. I personally
believe it is possible for reflected energy to wind up decreasing
the power consumption from the DC source that is supplying the finals,
which winds up decreasing the load on the 60 Hz power grid, which
decreases the oil required from the Middle East, which tends to
decrease the possibility of world war, which bodes well for the human
race, but that is another thread for another time.
--
73, Cecil http://www.qsl.net/w5dxp



-----= Posted via Newsfeeds.Com, Uncensored Usenet News =-----
http://www.newsfeeds.com - The #1 Newsgroup Service in the World!
-----== Over 100,000 Newsgroups - 19 Different Servers! =-----

On Fri, 11 Jun 2004 18:32:14 GMT, "Henry Kolesnik"
wrote:
What if the source doesn't or can't dissipate?

Hi Hank,

Simple enough to find out. Disconnect the output of your transmitter.
Set the drive level of your transmitter for full power. Defeat the
ALC. Key down. By the clock or watch, take notes at 1 minute
intervals for, say, 10 minutes. Prepare notes into report. Submit
report here. Total time to perform: 30 seconds - 30 minutes depending
mostly on access to the ALC defeat.

This answers all equivocations about does/doesn't; will/won't;
might/mightn't; could/couldn't; or can/can't. Think about it, you
have probably spent more time than that writing to and reading from
this thread to no certain conclusion.

73's
Richard Clark, KB7QHC

This place is where one can just about learn anything or nothing or learn
incorreclty. AKA the politics of reflections.

--
73
Hank WD5JFR
"Richard Clark" wrote in message
...
On Fri, 11 Jun 2004 18:32:14 GMT, "Henry Kolesnik"
wrote:
What if the source doesn't or can't dissipate?

Hi Hank,

Simple enough to find out. Disconnect the output of your transmitter.
Set the drive level of your transmitter for full power. Defeat the
ALC. Key down. By the clock or watch, take notes at 1 minute
intervals for, say, 10 minutes. Prepare notes into report. Submit
report here. Total time to perform: 30 seconds - 30 minutes depending
mostly on access to the ALC defeat.

This answers all equivocations about does/doesn't; will/won't;
might/mightn't; could/couldn't; or can/can't. Think about it, you
have probably spent more time than that writing to and reading from
this thread to no certain conclusion.

73's
Richard Clark, KB7QHC

Is there any objective reality when it comes to reflections? How do we
really know?

Henry Kolesnik wrote:

This place is where one can just about learn anything or nothing or learn
incorreclty. AKA the politics of reflections.

Well perhaps I should reword my comment. It seems like many responders are
getting into the politics of reflections, some into the theory but I believe
it's a science and should be explainable. Theories are used to explain what
goes on inside a black box that we can't open, just an input and output.
But a shorted 1/4 wave stub is about as far as you can get from a black
box.. I'm curious!
There are no stupid questions, just stupid people asking and that's me.

--
73
Hank WD5JFR
"Dave Shrader" wrote in message
news:Mp1zc.42427$HG.38082@attbi_s53...
Is there any objective reality when it comes to reflections? How do we
really know?

Henry Kolesnik wrote:

This place is where one can just about learn anything or nothing or
learn
incorreclty. AKA the politics of reflections.

Originally you asked:
so how does a stub work?

On Sun, 13 Jun 2004 19:21:19 GMT, "Henry Kolesnik"
wrote:

Well perhaps I should reword my comment.
snip complaint of politics
But a shorted 1/4 wave stub is about as far as you can get from a black
box.. I'm curious!

Hi Hank,

Seems like several many have offered the simple mechanics to satisfy
the question.

Would you like to comment why they did not? If you find the
reflection based argument tedious (and it can be that in spades); then
perhaps you should offer an outline of the terms to be employed or the
constraints of the stub's application to reduce shot-gun answers that
bloat the thread.

73's
Richard Clark, KB7QHC