Yuri Blanarovich wrote:
They must be inteligent smileys, with glasses 8-)
or divers 0-) or rich ones $-)

I'm not very internet savvy. What is an intelligent smiley?
--
73, Cecil http://www.qsl.net/w5dxp



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"Isn't a 50 ohm transmitter conjugately matched to a 50 ohm load
when fed through 1/2 wavelength of 450 ohm ladder-line?"

==============

Heck yes, I'm assuming u mean 50 + j 0 Ohms.

73 de Jack, K9CUN

Everybody keeps going on and on and on about 50-ohm transmitters when in
fact there's no such thing.

Gene Fuller wrote:
"The maximum power transfer theorem describes the impact from change of
the load impedance."

That`s true. When impedances at a junction become matched, you can cut
the matched line at any place and the impedances looking in opposite
directions are conjugates of each other.

It is not pathological to take full advantage of the theeorem. Conjugate
matching is the same as d-c matching except that reactance must be
neutralized not to get into the way of a-c maximum power transfer.

W.L. Everitt is one of many authors who state the maximum power transfer
theorem. I quoted Terman early in this thread. Here is a quote from
King, Mimno, annd Wing on page 43 of "Transmission Lines, Antennas, and
Wave Guides":

If a dissipationless network is inserted between a constant-voltage
generator of internal impedance ZG and a load of impedance ZR such that
maximum power is delivered to the load, at every pair of terminals the
impedances looking in opposite directions are conjugates of each other.
There`s lots more. Read the book.

Best regards, Richard Harrison, KB5WZI

On Wed, 3 Mar 2004 15:48:38 +0000 (UTC), "Reg Edwards"
wrote:
Everybody keeps going on and on and on about 50-ohm transmitters when in
fact there's no such thing.

Yes, you do keep going on and on about it, don't you? That and Q and
SWR meter alternative names - all pretty lame stuff.

Richard Harrison wrote:
If a dissipationless network is inserted between a constant-voltage
generator of internal impedance ZG and a load of impedance ZR such that
maximum power is delivered to the load, at every pair of terminals the
impedances looking in opposite directions are conjugates of each other.

Since dissipationless networks don't exist in reality, doesn't this imply
that it is impossible to achieve a conjugate match at *all* points in a
real-world system? - Not trying to be ornery, just realistic.
--
73, Cecil http://www.qsl.net/w5dxp



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Old Ed wrote:
"Couild you explain this concept, and/or provide some references?"

Suppose we adjust a variable d-c supply to full-scale indication on an
external meter. Next, install a chopper (lossless on-off circuit) driven
at a high frequency to produce a square wave interruption of the d-c
with a 50% duty cycle, and insert the chopper contacts in series with
the external meter.

The chopper connects the external meter 50% of the time and disconnercts
it 50% of the time. The meter reads 50% of full scale.

Another way to reduce the scale reading to 50% is to insert a resistor
in series with the meter. If it is an 0-1 ma meter and if it has an
internal resistance of 1000 ohms, insertion of a 1000-ohm resistor in
series with the meter will reduce the meter scale indication to 50%.

The chopper as part of the meter source eliminates current to the meter
50% of the time.

The resistor which has the same effect and produces the same scale
indication as the chopper on the effective output current exacts its
loss of 0.0005 amp x 0.5 volt or 0.25 milliwatt during 100% of the time.

The chopper eliminates the power-losing resistor by substituting
off-time in the power source. The source only supplies the power used by
the load. With a resistor limiting power to the load, the source
supplies its loss and the load power.

The power in the load, a meter in our example, is the same using either
the resistor or the chopper. The resistor is analogous to a Class-A
amplifier. The chopper is analogous to a Class-C amplifier.

The off-time has the same effective opposition to current to a load as a
dissipative resistance. As the time-limited currented opposition to load
current consumes no power, it is called a dissipationless resistance.

Best regards, Richard Harrison, KB5WZI

It is in the same class of parts with inductancless inductors,
and capacitanceless capacitors are in.
With lossless resistance they can form
a lossless, non-energy storing, extremely low/high Q, network.
No need for tuning either!
(sorry-just not serious today)




"Old Ed" wrote in message
hlink.net...
"Lossless resistance?" Would that be zero resistance,
or perhaps a negative resistance, as in the active part of
a tunnel diode's V-I characteristic?

I am a career EE, with a couple of graduate EE degrees;
and this is something entirely new to me. Could you explain
this concept, and/or provide some references?

Thanks, Ed

"Richard Clark" wrote in message
...
On Wed, 3 Mar 2004 15:48:38 +0000 (UTC), "Reg Edwards"
wrote:
Everybody keeps going on and on and on about 50-ohm transmitters when in
fact there's no such thing.

Yes, you do keep going on and on about it, don't you? That and Q and
SWR meter alternative names - all pretty lame stuff.

and on, and on, and on, and on... i knew this would be a good thread.

John Smith wrote:
"It is in the same class of parts with inductanceless inductors, and
capacitanceless capacitors are in."

Lossless resistance makes volts per amp. Inductors and capacitors are
lossless because they only store energy and give it all back.

A lossless resistance stores no energy. Its action is immediate.

An inductance or capacitance with zero reactance also stores no energy
and makes no volts per amp as opposition.

Best regards, Richard Harrison, KB5WZI