On 2/2/2011 10:26 AM, Michael Germino wrote:
> I only used it if I have a problem. I used it to see where the best
> placement of the ferrite was. Sometimes where you think the placement is
> best, isn't.
Not necessarily. Every wire (or conductor) is an antenna, whether we
like it or not. A good ferrite choke acts like an open circuit, whereas
a poor one (not enough turns) acts like an inductor, and one with too
many turns can look capacitive. A choke simply ADDS its impedance in
series with the existing antenna. If it's an optimum choke (near its
resonance and a high impedance), it acts like an insulator to stop
current AT THAT POIINT, but if the wire is long enough, the choke might
turn the remaining wire into a half wave and increase the current in
that part of the wire. Ditto with the choke that is L or C -- it simply
shifts the current maxima and minima along that particular antenna.
Bottom line -- measuring (or sensing) current in these conductors is
certainly a worthwhile thing, but it's easy to mis-interpret the results
if you don't view what you see in the light of the fundamental concepts
of antennas.
73, Jim K9YC
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