I am surprised that YO or 4nec2 don't include actual current measurement
in the parasitic elements. EZNEC includes a table of current amplitude and
phase for each segment of each element. However the phase reference is
not stated anywhere that I know about. The phase angle in the table could
be phase of current to voltage or phase of the parasitic to the driven
element
which, it seems to me, must be known to be useful. I will appreciate if any
can answer what the phase is reference to.
PS what is meant by "REF + DIR" ?
k7puc
----- Original Message -----
From: "Jim Thomson" <jim.thom@telus.net>
To: <towertalk@contesting.com>
Sent: Wednesday, December 22, 2010 6:15 AM
Subject: [TowerTalk] RF current in REF + DIR ..how much ?
> How much RF current typ flows in the REF + DIR on a 3-el yagi ? YO
> just shows a 'relative' scale for the parasitic ele's.
> IE: just to simplify things, let's say we have 10A flowing into the 30
> ohm feed-point of the DE [3 kw] . [monoband yagi]
> How much RF current do we typ have at the center of the REF + DIR ??
> [as a percentage of the DE current] 10%, 30% ??
>
> If the REF + DIR used solid fiberglass center insulator's and the
> shorting strap across em was removed, and an RF ammeter
> was strapped across the insulator, what would I expect ? Is that method
> valid ? I was thinking a clamp on RF Ammeter
> could also be used, but typ they are not calibrated..but are only
> relative. Has anybody ever tried to measure the RF current in the
> center of the parasitic ele's ?? I downloaded 4NEC2 a few days
> ago....so it's new to me..and at 1st glance, I don't see any mention
> of exact current flow in the parasitic els. Now of course, this will all
> depend on the tuning and spacing of the parasitic ele's....and
> relative current flow in the parasitic ele's could vary across the band.
>
> Tnx in advance....... Jim VE7RF
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