
March 31st 09, 08:02 PM
posted to rec.radio.amateur.antenna
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First recorded activity by RadioBanter: Jul 2006
Posts: 666
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colinear representation in NEC
Cecil Moore wrote:
Jim Kelley wrote:
Why not take some actual phase shift measurements for yourself?
I have already done that at my previous QTH and
reported it two years ago. Remember these graphs
from software that you recommended?
http://www.w5dxp.com/travstnd.gif
My dual-trace scope measurements agreed within
the accuracy to which I could measure.
Point is that the delay through a transmission
line, a wire, or a coil is the same no matter
what type of current (standing wave or traveling
wave) is flowing. EM waves are EM waves. If the
current is primarily standing wave current with
essentially unchanging phase, the phase shift
in the standing wave current is unrelated to the
delay through the T-line, wire, or coil. Yet
standing wave current phase is what was used to
"prove" a 3 nS delay through a 100T, 2" dia, 10TPI
coil on 75m. If traveling wave current had been
used, as I did on my 75m Texas Bugcatcher coil,
the delay would have been shown to be ~26 nS.
In a 1/4WL monopole or 1/2WL dipole, the total
current is about 90% standing wave current.
Did you take a look at the current phase in these
two inverted-Vs?
http://www.w5dxp.com/inv_v.EZ
http://www.w5dxp.com/inv_vt.EZ
It's like having a conversation with a recorded message.
ac6xg
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