View Single Post
  #114   Report Post  
Old January 8th 08, 07:39 AM posted to rec.radio.amateur.antenna
Richard Clark Richard Clark is offline
external usenet poster
 
First recorded activity by RadioBanter: Jul 2006
Posts: 2,951
Default Standing morphing to travelling waves. was r.r.a.a Laugh Riot!!!

On Mon, 7 Jan 2008 21:03:35 -0500, "AI4QJ" wrote:

Well, you said the only way to measure SWR on a receive antenna is by
measuring current (sort of as an aside). I wanted to know the significance
of that. Now I know that the reason you said that was to support your SWR
calculation for a receive antenna using EZNEC, which is based on current
(method of moments). You were not saying it in terms of making physical
measurements but only to support the accuracy of your statement (i.e.
there's no better way to determine SWR on a receiving antenna than to
measure current, and, EZNEC is based on current). I know this was not your
main point, it was just an aside, but I don't agree with it; however, that
in itself does not diminish your main point.


Hi Dan,

It is merely a response to the "framing" of a specific expectation
within the context of Cecil's citation. The citation demanded an
externality, I supplied a stimulus external to the antenna.

However, this does not mean that there is no other indicator of
Standing Waves on a Traveling Wave antenna, and it does not make this
exotic testing the only proof of Standing Waves on a Traveling Wave
antenna. There is, after all, the concept of reciprocity.

If you look at the reciprocal actions offered by exciting a Traveling
Wave antenna with a source directly attached to it (and Cecil's last
example proves this), you find Standing Waves. This may confound the
SWR meter, but then that meter doesn't indicate what is on the wires,
it indicates what is impressed upon the finals.

Now, if you want to discard EZNEC (which for some odd reason you seem
to approach method of moments with a sneer), conventional methods
would still bear out the same results. Lord knows I've sat at the
bench doing it the conventional way for thousands of measurements.
I've probably made more physical measurements in a day, than anyone
here has in a lifetime.

Others, don't bore us with indignities about all your SWR meter
readings in reply to that last statement. :-)

So now to the shoe you dropped:
I know this was not your
main point, it was just an aside, but I don't agree with it


What was my main point, and how is yours conflict with it? Is yours a
philosophical triviality so common to these threads, or does it come
with physical measurements experience?

73's
Richard Clark, KB7QHC