RadioBanter - View Single Post

March 15th 06, 07:56 PM posted to rec.radio.amateur.antenna

wrote:

Food for thought.

At this moment in time it seems Cecil is claiming an inductor acts like
so many electrical degrees, but of course at any moment another waffle
might pops out of the Texas toaster and change everything.

That's not food for thought. That's emotional gut feelings. I
thought we agreed to cease and desist from ad hominem attacks?

Let's assume we have a mobile antenna that is 25 electrical degrees
tall. Now following the logic a loading coil acts like a transmission
line, we have a 65-degree loading coil.

*False assumption!* The phase delay through the coil is what it
is and we don't know exactly what it is. We do know it is not what
has been measured and reported using a signal source (standing wave
current) that doesn't ever change phase.

Our present choice is between a reported measurement that is
100% flawed, in the absolute sense of the word, and an estimate
with unknown accuracy based on the laws of physics. Given those
two, and only two, present choices, which choice should one make?

Please see the end of this posting for a description of the
logical diversion that is taking place here.

The phase delay through the coil is what it is and we don't know
exactly what it is. We do know it is not zero as the standing wave
current phase shift measurement would predict.

Let me focus the subject of the argument back upon the actual
subject of the argument and try to avoid diversions into the
unknown, like the above.

How does one measure the phase delay through a coil or wire
using a signal with forever unchanging phase? All of the phase
delay experiments so far have used the above flawed method.
So far, we only have experimental measurements that are flawed
except for the self-resonant experiments.

Which is preferred? The results from experiments known to
be 100% flawed or estimates with unknown accuracy based on
the laws of physics? Those are presently our only two choices.

Following the same twisted logic, since the loading inductor is
65-degrees long, we should be able the move it anywhere in the antenna
without changing antenna tuning.

*False assumption!* The superposition of all four of the
forward and reflected waves is much more complicated than that.

Our 75 meter antenna should also work on 25 meters as a 3/4 wave
antenna, and on 37.5 meters as a half-wave.

It's not as simple as that but I have the EZNEC current
distribution patterns that indicate something akin to
that indeed does develop. Give me a few hours and I
will post those results.

Where are the design equations we can all use?

Asked and answered but not sure of the accuracy applied
to 75m bugcatcher loading coils. Someone is working on
that. Please stand by.

The logical diversion that is happening here goes like this:

Person A says: "The moon is 10,000 miles from the earth.

Person B says: "That can't be true."

Person A says: "How far do you say the moon is from the earth?"

Person B says: "I don't know, but I do know it is not 10,000
miles."

Person A says: "Well, if you don't know and can't give me the
correct answer, I am right and you are wrong. The moon is
10,000 miles from the earth."

Does an absolutely false answer beat ignorance?
--
73, Cecil http://www.qsl.net/w5dxp