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The following scans are for various types of coils. Based on the
following equations I wanted to "wind my own". This coil was
wound on a 1/2" PVC pipe with 27 turns. As shown in
Wikipedia. See QST,
May 2008, Technical Correspondence on page 50, "Coupling problems to short
antennas" for a good discussion on coils.
- - -
Coil data
| Description |
Dimension |
|
Form Diameter |
0.875" |
|
Wire |
14 awg
THHN (covered) |
|
Wire diameter |
0.0641" |
|
Coil diameter(OD) |
1.00" |
|
Turns |
27 |
|
Coil Length |
3.00" |
| |
|
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Inductance - Calculated and Measured
Frequency
(MHz) |
Impedance
(calculated) |
Impedance
(measured) |
| 3.5 |
116.113
Ω |
102.903 Ω |
| 7.1 |
235,544
Ω |
234.501 Ω |
| 14.2 |
471.088
Ω |
851.629 Ω |
- - -
Coil picture
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Full scan - 1 to 180 MHz
The coil is resonant at 20.0393 MHz. Above this frequency the coil
looks capacitive, most likely due to the capacitive coupling between
windings due to the thickness of the insulation.
- - -
80 meter scan
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Links:
AntennaGraphs.com - Ringo Ranger II - SWR Scan
http://www.qsl.net/k6mlo/
If you have any graphs that could be added to
this site please send them along. I'll post and credit your
information. |
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