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Old August 24th 03, 09:40 PM
W5DXP
 
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Peter O. Brackett wrote:
I beleive in working it all out from first principles, can't trust anybody
else, except of course you and your wonderful programs. :-)


Ever try to develop Morse code from first principles? :-)
--
73, Cecil http://www.qsl.net/w5dxp



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  #72   Report Post  
Old August 24th 03, 10:01 PM
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Dr. Slick wrote:
I've got the same paper. It's a bit confusing, because then he
calls [s]**2 = [(ZL - Zo*) / (ZL + Zo)]**2 the "power reflection
coefficent". Where if you take the square root to the power reflection
coefficient, you should get the voltage r. c. So perhaps s =
(ZL - Zo*) / (ZL + Zo) really IS the voltage R. C., even in this paper!


There's no confusion at all (except here on this newsgroup). The power
reflection coefficient is known as the "Reflectance" in optics. The
voltage reflection coefficient that we know and love in RF is one
of the Fresnel (1788-1827) Equations. In optics, it is known as the
"amplitude reflection coefficient", equation 4.34 in _Optics_, 4th edition.

May I suggest that everyone obtain a copy of _Optics_, by Hecht, and
contribute to his/her basic understanding of EM waves. Light was
detectable eons before RF and thus had an extreme head start. We are
presently arguing principles that were already resolved by the end of
the 18th century.
--
73, Cecil http://www.qsl.net/w5dxp



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Old August 24th 03, 11:39 PM
Tdonaly
 
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OHH MY GHOD!! Your sooo smart to find my real name!

(slaps head in stupidity, i forgot about a Google search, Dammit!)




Slick


Ah, the fatuous irony of youth. Say, Yee, I'm curious. Did you ever attend
Lowell? Also, what got you interested in radio? I would think a self-anointed
artist cum musician like you would avoid technical subjects like the
plague. You don't seem to be doing very well at any rate.
73,
Tom Donaly, KA6RUH


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Old August 24th 03, 11:42 PM
Tdonaly
 
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Sorry Peter, quantum physics disagrees with you. It's the electrons,
photons, and virtual photons that are real. :-)
--
73, Cecil http://www.qsl.net/w5dxp


What's the radius of a virtual photon, Cecil?
73,
Tom Donaly, KA6RUH
  #76   Report Post  
Old August 25th 03, 02:07 AM
Dr. Slick
 
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"Peter O. Brackett" wrote in message link.net...
Slick:

[snip]
Correction: rho = (Z - conj(R))/(Z + (R)), the conjugate being
only in the denominator.

Slick

[snip]

Well here we have to part company.

Not using the same "thing" in both numerator and denominator *is* being
inconsistent!

See my algebraic development in another posting on this thread.



Opps Again!

Correction: rho = (Z - conj(R))/(Z + (R)), the conjugate being
only in the numerator.


Slick
  #77   Report Post  
Old August 25th 03, 02:12 AM
Peter O. Brackett
 
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Cecil:

[snip]
Ever try to develop Morse code from first principles? :-)
--
73, Cecil http://www.qsl.net/w5dxp

[snip]

Even Morse didn't do that! Apparently historians believe that his faithful
servant Vail did that.

--
Peter K1PO
dah di dah


  #78   Report Post  
Old August 25th 03, 02:22 AM
Dr. Slick
 
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"David Robbins" wrote in message ...
"Dr. Slick" wrote in message
om...

[s]**2 = [(ZL - Zo*) / (ZL + Zo)]**2 the "power reflection
coefficent".

Note the squares.

yes, please do note the squares.... and remember, just because

[s]**2 = [(ZL - Zo*) / (ZL + Zo)]**2
does NOT mean that
s = (ZL - Zo*) / (ZL + Zo)

this is the one big trap that all you guys that like to use power in your
calculations fall into. just because you know the power doesn't mean that
you know squat about the voltage and current on the line. you can not work
backwards. that is why it is always better to work with voltage or current
waves and then in the end after you have solved all those waves you can
always calculate power if you really need to know it.



yes, but he does say that s = (ZL - Zo*) / (ZL + Zo) , first.

But he foolishly calls it a "power wave R. C."

Then he squares the magnitudes [s]**2 = [(ZL - Zo*) / (ZL +
Zo)]**2

And calls this the "power R. C."


The bottom label is fine, we've all see this before, as the ratio
of the RMS incident and reflected voltages, when squared, should give
you the ratio of the average incident and reflected powers, or the
power R. C.


But to call the voltage reflection coefficient a "power wave R.
C."
is really foolish, IMO.


Slick
  #79   Report Post  
Old August 25th 03, 02:55 AM
Tdonaly
 
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Design, development and test of circuit and board level RF designs
including impedance matching networks (simulating on MIMP) for E-PHEMT
power amplifiers for the GSM, DCS, and PCS cellular bands
(880MHz-1900MHz). Simulations on ADS to assess manufacturability and
robustness. Bias tuning for EDGE mode EVM and Adjacent channel power.
Optimize circuit design and board layout for PAE, gain flatness,
stability under mismatched loads, receive-band noise, AM to PM, input
VSWR and harmonic suppression.
Design and construction of FM stereo multiplexed Phase Locked
Loop transmitters, broadband design (88-108MHz). Design and selection
of VCOs, pre-scalers, and loop filters. Antenna design and
construction: 5/8ths vertical groundplane, 1/4 wavelength, and
dipoles. Compressor-limiter and Chebychev Low-pass filter design.
Microwave (MMIC) testing and tuning (2-18GHz). Design of
equalizers and filters. Linearity of Detector Logarithmic Video
Amplifiers. Temperature compensation networks.


You win a prize if you can guess where i last worked...

Your turn Tom...


Slick


Very impressive. You've designed 5/8s vertical ground planes,
1/4 wavelength [something or others, I guess] and dipoles.
Where are you working now? Did you go to Lowell?
73,
Tom Donaly, KA6RUH
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Old August 25th 03, 03:45 AM
W5DXP
 
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Tdonaly wrote:
What's the radius of a virtual photon, Cecil?


From _Optics_, by Hecht: "When two electrons repel one another, or an
electron and proton attract, it is by emitting and absorbing virtual
photons and thereby transferring momentum from one to the other, ...
Virtual photons can never escape to be detected directly by some
instrument."
--
73, Cecil http://www.qsl.net/w5dxp



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