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Old March 25th 09, 12:24 AM posted to rec.radio.amateur.antenna
Cecil Moore[_2_] Cecil Moore[_2_] is offline
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First recorded activity by RadioBanter: Mar 2007
Posts: 3,521
Default colinear representation in NEC

Jim Kelley wrote:
He wasn't measuring "standing wave current", whatever that is.


Sorry Jim, of course he was, since standing wave current
is the primary current that exists on standing wave
antennas like the antenna Roy used to measure his currents.

You keep saying "whatever that is" when it is well
defined in most any antenna book. That you don't
understand standing wave current on standing wave
antennas is just a statement of ignorance - no
offense intended - apparently Roy is just as ignorant.

Perhaps you should study and understand the
difference between a standing wave antenna like
a dipole and a traveling wave antenna like a
terminated Rhombic. Balanis has a good discussion
of such. Here's a quote: "Standing wave antennas,
such as the dipole, can be analyzed as traveling
wave antennas with waves propagating in opposite
directions (forward and backward) and represented
by traveling wave currents..."

An inverted-V dipole can be converted from a
standing wave antenna to a traveling wave antenna
by terminating the ends with a load connected to
mininec ground. Here is an inv_V and a terminated
inv_V modeled in EZNEC. Please look at the "Currents"
display until you understand the meaning of the
phase angles.

http://www.w5dxp.com/inv_v.EZ (standing wave antenna)

Phase angle of the current varies by 2.72 degrees
along each 90 degrees of antenna. This is the current
that Roy used.

http://www.w5dxp.com/inv_vT.EZ (traveling wave antenna)

Phase angle of the current varies by 90 degrees
along each 90 degrees of antenna. This is the current
that Roy should have used.
--
73, Cecil, IEEE, OOTC, http://www.w5dxp.com
"Government 'help' to business is just as disastrous as government
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