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Old October 3rd 07, 11:27 PM posted to rec.radio.amateur.antenna
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Posts: 797
Default "Quarter wave ground mounted radials are a waste of wire."


"Richard Harrison" wrote in message
...
Dave wrote:
"You don`t even need reflections. A properly terminated piece of wire
has a different current at every point along the wire."

Instantaneous values, of course. But, proper termination means no
reflection. The only source of variation along a line other than
attenuation is reflection. In a uniform line, attenuation causes a
steady decline of energy as energy travels. With a lossless line,
properly terminated, variation of rnergy along a line is only the phase
produced instantaneois values along the line. These are resolved during
the period of a cycle by the root mean square calculation.

Best regards, Richard Harrison, KB5WZI


and what is wrong with instantaneous values? lacking a requirement to talk
in peak, phasor, rms, or some other averaging method it is perfectly valid
to assume instantaneous measurements. and if I remember right we were
talking of measuring current, not energy. and time is a valid parameter
when measuring current, just hook up your o-scope and measure away...
measure that current on each end of a wire, or coil, or coax, with a dual
trace scope and see the difference! throw away that silly-wire-reader thing
and get back to the basics. get a pulse generator and build yourself a
reflectometer and make use of those reflections!


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Old October 4th 07, 04:05 AM posted to rec.radio.amateur.antenna
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Default "Quarter wave ground mounted radials are a waste of wire."

Dave wrote:
and what is wrong with instantaneous values?


Nothing if presented as part of the context,
confusing if not since most people would
assume the context is RMS. Do I have 110v
AC in my house? You can argue that the answer
is "no" but you would need to state the context.
--
73, Cecil http://www.w5dxp.com
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Old October 4th 07, 06:24 PM posted to rec.radio.amateur.antenna
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Default "Quarter wave ground mounted radials are a waste of wire."



Richard Harrison wrote:

Dave wrote:
"You don`t even need reflections. A properly terminated piece of wire
has a different current at every point along the wire."

Instantaneous values, of course. But, proper termination means no
reflection. The only source of variation along a line other than
attenuation is reflection.


The only electromagnetic currents 'flowing' on a transmission line are
the currents which result from the reflected and/or the forward
electromagnetic waves. Neither of these currents varies periodically
along the line (except as noted, instantaneously).

73, ac6xg




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