At 06:48 PM 7/25/2007, jeremy-ca wrote:
>On higher HF and 6M simply winding all the turns in one direction adds a lot
>of capacitance which defeats the effectiveness.
I wonder if this can be quantified..
Say you have two pieces of coax side by side that are 1 meter long
(about 1 foot loop diameter). Say the spacing is twice the thickness
of the jacket.. call it 2 mm total?
Further, let's be pessimistic, and say it's a 1 cm wide plate
separated by 2mm. So we have
C = 8.85E-12 * 1 meter * 0.01 meter/0.002 meter = 8.85E-12 * 5 =
about 45 pF... that's pretty big at 50 MHz.. about 70 ohms impedance.
String 4 of those in series (as if you had 5 parallel coils) and
you're up to about 300 ohms.
Interesting...
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